{"id":1305,"date":"2024-08-10T17:47:05","date_gmt":"2024-08-10T09:47:05","guid":{"rendered":"http:\/\/www.spiceandwolf.com.cn\/?p=1305"},"modified":"2026-03-10T20:38:30","modified_gmt":"2026-03-10T12:38:30","slug":"interview-java-basic","status":"publish","type":"post","link":"http:\/\/www.spiceandwolf.com.cn\/index.php\/interview-java-basic\/","title":{"rendered":"java\u57fa\u7840\u9762\u8bd5\u9898"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">\u5355\u4f8b\u6a21\u5f0f\u6709\u54ea\u51e0\u79cd\u5b9e\u73b0\u65b9\u5f0f\uff1f<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u997f\u6c49\u5f0f\u3002\n<ul class=\"wp-block-list\">\n<li>\u4f18\u70b9\uff1a\u7ebf\u7a0b\u5b89\u5168\uff0c\u56e0\u4e3a\u7c7b\u7684\u5b9e\u4f8b\u5f15\u7528\u662f\u9759\u6001\u7684\u4e14\u8d4b\u4e86\u521d\u59cb\u503c\uff0c\u6240\u4ee5Java\u865a\u62df\u673a\u4f1a\u5728\u7c7b\u52a0\u8f7d\u7684\u521d\u59cb\u5316\u9636\u6bb5\u4fdd\u8bc1\u8fd9\u4e2a\u9759\u6001\u5b9e\u4f8b\u5bf9\u8c61\u521b\u5efa\u7684\u7ebf\u7a0b\u5b89\u5168\u6027\u3002<\/li>\n\n\n\n<li>\u7f3a\u70b9\uff1a\n<ul class=\"wp-block-list\">\n<li>\u6ca1\u6709\u5ef6\u8fdf\u521d\u59cb\u5316\uff0c\u5982\u679c\u7c7b\u52a0\u8f7d\u548c\u521b\u5efa\u5b9e\u4f8b\u8017\u65f6\u8f83\u957f\uff0c\u5982\u679c\u5728\u5e94\u7528\u542f\u52a8\u65f6\u5c31\u9700\u8981\u8fdb\u884c\u8be5\u7c7b\u7684\u7c7b\u52a0\u8f7d\uff0c\u5e76\u4e14\u5e0c\u671b\u5e94\u7528\u80fd\u5feb\u542f\u52a8\u65f6\uff0c\u53ef\u80fd\u5e76\u4e0d\u9002\u7528\uff0c\u5177\u4f53\u6839\u636e\u5b9e\u9645\u60c5\u51b5\u5224\u65ad\uff1b<\/li>\n\n\n\n<li>\u7c7b\u52a0\u8f7d\u540e\u5982\u679c\u4e00\u76f4\u6ca1\u6709\u88ab\u4f7f\u7528\u5230\uff0c\u4f1a\u6301\u7eed\u5360\u636e\u5185\u5b58\u7a7a\u95f4\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Singleton {\n    private static Singleton instance = new Singleton();\n\n    private Singleton() {}\n\n    public static Singleton getInstance() {\n        return instance;\n    }\n}<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u61d2\u6c49\u5f0f\u3002\n<ul class=\"wp-block-list\">\n<li>\u4f18\u70b9\uff1a\u5ef6\u8fdf\u521d\u59cb\u5316\uff0c\u53ea\u5728\u9700\u8981\u65f6\u624d\u4f1a\u521b\u5efa\u7c7b\u5b9e\u4f8b\uff0c\u8282\u7701\u4e86\u5185\u5b58\u7a7a\u95f4\u3002<\/li>\n\n\n\n<li>\u7f3a\u70b9\uff1a\u61d2\u6c49\u6a21\u5f0f\u9700\u8981\u81ea\u884c\u4fdd\u8bc1\u5b9e\u4f8b\u521b\u5efa\u8fc7\u7a0b\u4e2d\u7684\u7ebf\u7a0b\u5b89\u5168\u6027\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ synchronized\u7ebf\u7a0b\u540c\u6b65\u65b9\u5f0f\npublic class SynchronizedSingleton {\n    private static SynchronizedSingleton instance;\n\n    private SynchronizedSingleton() {}\n\n    public synchronized static SynchronizedSingleton getInstance() {\n        if (instance == null) {\n            instance = new SynchronizedSingleton();\n        }\n        return instance;\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ \u53cc\u91cd\u68c0\u67e5\u9501\u7ebf\u7a0b\u540c\u6b65\u65b9\u5f0f\npublic class DoubleCheckLockSingleton {\n    private static volatile DoubleCheckLockSingleton instance;\n\n    private DoubleCheckLockSingleton() {}\n\n    public static DoubleCheckLockSingleton getInstance() {\n        if (instance == null) {\n            synchronized (DoubleCheckLockSingleton.class) {\n                if (instance == null) {\n                    instance = new DoubleCheckLockSingleton();\n                }\n            }\n        }\n        return instance;\n    }\n}<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9759\u6001\u5185\u90e8\u7c7b\u3002\u9759\u6001\u5185\u90e8\u7c7b\u4e0d\u4ec5\u5b9e\u73b0\u4e86\u5ef6\u8fdf\u521d\u59cb\u5316\u8fd8\u4fdd\u8bc1\u4e86\u7ebf\u7a0b\u5b89\u5168\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>public class StaticInnerClassSingleton {\n\n    private static class StaticInnerClass {\n        private static final StaticInnerClassSingleton instance = new StaticInnerClassSingleton();\n    }\n\n    private StaticInnerClassSingleton() {}\n\n    public StaticInnerClassSingleton getInstance() {\n        return StaticInnerClass.instance;\n    }\n}<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/blog.csdn.net\/qq_43842093\/article\/details\/123962138\">\u679a\u4e3e\u65b9\u5f0f<\/a>\u3002\u679a\u4e3e\u65b9\u5f0f\u7684\u5355\u4f8b\u6a21\u5f0f\uff0c\u4e0d\u4f46\u7ebf\u7a0b\u5b89\u5168\uff0c\u4e14\u81ea\u52a8\u652f\u6301\u5e8f\u5217\u5316\u673a\u5236\uff0c\u4e0d\u5149\u5982\u6b64\uff0c\u8fd8\u80fd\u9632\u6b62\u901a\u8fc7\u53cd\u5c04\u673a\u5236\u62ff\u5230\u79c1\u6709\u6784\u9020\u65b9\u6cd5\u8fdb\u884c\u5b9e\u4f8b\u5316\uff0c\u662f\u73b0\u6709\u5355\u4f8b\u6a21\u5f0f\u4e2d\u7684\u6700\u4f18\u89e3\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Singleton {\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public enum SingletonEnum {\n    INSTANCE;\n    private Singleton instance;\n    private SingletonEnum() {\n        try {\n            TimeUnit.SECONDS.sleep(2);\n        } catch (InterruptedException e) {\n            throw new RuntimeException(e);\n        }\n        instance = new Singleton();\n    }\n    public Singleton getInstance() {\n        return instance;\n    }\n\n    public static void main(String&#91;] args) {\n        for (int i = 1; i &lt;= 50; i++) {\n            new Thread(() -&gt; {\n                Singleton ins = SingletonEnum.INSTANCE.getInstance();\n                System.out.println(Thread.currentThread().getName() + \"\\t:\\t\" + ins);\n            }, \"Thread\" + String.valueOf(i)).start();\n        }\n    }\n}<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">StringBuffer\u548cStringBuilder\u7684\u533a\u522b\uff1f<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5171\u540c\u70b9\u3002\u6709\u5171\u540c\u7236\u7c7bAbstractStringBuilder\uff0c\u90fd\u5b9e\u73b0\u4e86Serializable\u548cCharSequence\u63a5\u53e3\uff0c\u4f7f\u7528\u7684\u65b9\u6cd5\u57fa\u672c\u4ee5\u7236\u7c7b\u4e3a\u84dd\u672c\u3002<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"760\" height=\"152\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-2.png\" alt=\"\" class=\"wp-image-1319\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-2.png 760w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-2-300x60.png 300w\" sizes=\"auto, (max-width: 760px) 100vw, 760px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"734\" height=\"136\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-3.png\" alt=\"\" class=\"wp-image-1320\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-3.png 734w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-3-300x56.png 300w\" sizes=\"auto, (max-width: 734px) 100vw, 734px\" \/><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e0d\u540c\u70b9\u3002\n<ul class=\"wp-block-list\">\n<li>\u52a0\u5165\u7248\u672c\u4e0d\u540c\u3002StringBuffer\u57281.0\u7248\u672c\u52a0\u5165\u5230JDK\u4e2d\uff0cStringBuilder\u57281.5\u7248\u672c\u52a0\u5165\u5230JDK\u4e2d\u3002<\/li>\n\n\n\n<li>\u6027\u80fd\u3002\u5355\u7ebf\u7a0b\u60c5\u51b5\u4e0b\uff0cStringBuilder\u6548\u7387\u9ad8\u4e8eStringBuffer\u3002<\/li>\n\n\n\n<li>\u4f18\u5316\u70b9\u3002StringBuffer\u6709\u4e00\u4e2a\u5b57\u7b26\u6570\u7ec4\u6210\u5458\u53d8\u91cftoStringCache\uff0c\u5728\u5b57\u7b26\u4e32\u4e0d\u53d8\u7684\u60c5\u51b5\u4e0b\uff0c\u7528\u6765\u7ed9new String(char[], boolean)\u4f5c\u4e3a\u5bf9\u8c61\u521b\u5efa\u7684\u53c2\u6570\uff0c\u907f\u514d\u9891\u7e41\u7684\u5b57\u7b26\u6570\u7ec4\u6df1\u62f7\u8d1d\u64cd\u4f5c\u3002<\/li>\n\n\n\n<li>\u7ebf\u7a0b\u5b89\u5168\u6027\u3002StringBuffer\u7684\u65b9\u6cd5\u4e0a\u90fd\u6709synchronized\u5173\u952e\u5b57\u4fee\u9970\uff0cStringBuilder\u65b9\u6cd5\u6ca1\u6709\u7528synchronized\u5173\u952e\u5b57\u4fee\u9970\uff0cappend(String str)\u65b9\u6cd5\u524d\u8005\u80fd\u6709\u6548\u4fdd\u969c\u7ebf\u7a0b\u5b89\u5168\uff0c\u540e\u8005\u5219\u53ef\u80fd\u62a5ArrayIndexOutOfBoundsException\u5f02\u5e38\uff1a<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>public class StringBufferAndStringBuilder {\n    public static void stringBufferConnect(StringBuffer stringBuffer, int s) {\n        try {\n            TimeUnit.MICROSECONDS.sleep(1);\n        } catch (InterruptedException e) {\n            throw new RuntimeException(e);\n        }\n        for (int i = 0; i &lt; 100; i++) {\n            stringBuffer.append(String.valueOf(s));\n        }\n    }\n\n    public static void stringBuilderConnect(StringBuilder stringBuilder, int s) {\n        try {\n            TimeUnit.MICROSECONDS.sleep(1);\n        } catch (InterruptedException e) {\n            throw new RuntimeException(e);\n        }\n        for (int i = 0; i &lt; 100; i++) {\n            stringBuilder.append(String.valueOf(s));\n        }\n    }\n\n    public static void main(String&#91;] args) throws InterruptedException {\n        StringBuffer stringBuffer = new StringBuffer();\n        StringBuilder stringBuilder = new StringBuilder();\n        List&lt;Thread&gt; threadList = new ArrayList&lt;&gt;();\n        for (int i = 0; i &lt; 200; i++) {\n            int finalI = i;\n            Thread tempThread = new Thread(() -&gt; {\n                stringBufferConnect(stringBuffer, finalI);\n                stringBuilderConnect(stringBuilder, finalI);\n            }, String.valueOf(i));\n            threadList.add(tempThread);\n            tempThread.start();\n        }\n\n        for (Thread thread : threadList) {\n            thread.join();\n        }\n\n        System.out.println(stringBuffer.toString());\n        System.out.println(stringBuffer.length());\n\n        System.out.println(stringBuilder.toString());\n        System.out.println(stringBuilder.length());\n    }\n}<\/code><\/pre>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"424\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-4-1024x424.png\" alt=\"\" class=\"wp-image-1321\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-4-1024x424.png 1024w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-4-300x124.png 300w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-4-768x318.png 768w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-4-1536x635.png 1536w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-4-2048x847.png 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>\u8fd9\u91ccStringBuffer\u53ea\u80fd\u4fdd\u8bc1\u6700\u540e\u5b57\u7b26\u957f\u5ea6\u4e00\u81f4\uff0c\u56e0\u4e3a\u662f\u5faa\u73afappend\uff0c\u6240\u4ee5\u5e76\u4e0d\u80fd\u4fdd\u8bc1\u5b57\u7b26\u4e32\u62fc\u63a5\u7684\u987a\u5e8f\u3002StringBuffer\u7c7b\u5e76\u4e0d\u662f\u5b8c\u5168\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u50cfappend(char[] str, int offset, int len)\u65b9\u6cd5\uff0c\u6570\u7ec4\u5f15\u7528\u7834\u574f\u4e86\u9501\u7684\u5bf9\u5185\u90e8\u5bf9\u8c61\u7684\u540c\u6b65\u63a7\u5236\uff0c\u5bfc\u81f4\u5916\u90e8\u5bf9\u8c61\u4f9d\u7136\u80fd\u5bf9\u6570\u7ec4\u8fdb\u884c\u64cd\u4f5c\uff0c\u5904\u7406\u4e0d\u614e\u4f9d\u7136\u4f1a\u62a5\u7d22\u5f15\u6ea2\u51fa\u5f02\u5e38\u3002<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"299\" src=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-5-1024x299.png\" alt=\"\" class=\"wp-image-1322\" srcset=\"http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-5-1024x299.png 1024w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-5-300x88.png 300w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-5-768x224.png 768w, http:\/\/www.spiceandwolf.com.cn\/wp-content\/uploads\/2024\/08\/image-5.png 1234w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5e94\u7528\u573a\u666f\u3002\n<ul class=\"wp-block-list\">\n<li>\u5355\u7ebf\u7a0b\u573a\u666f\u4e0bStringBuilder\u4f18\u4e8eStringBuffer\u3002<\/li>\n\n\n\n<li>\u591a\u7ebf\u7a0b\u5e76\u53d1\u91cf\u5c11\u7684\u573a\u666f\u4e0b\u53ef\u4ee5\u4f7f\u7528StringBuffer\uff0c\u903b\u8f91\u5b9e\u73b0\u66f4\u65b9\u4fbf\u3002<\/li>\n\n\n\n<li>\u591a\u7ebf\u7a0b\u9ad8\u5e76\u53d1\u573a\u666f\u4f7f\u7528StringBuilder\u5e76\u81ea\u884c\u7f16\u5199\u5e76\u53d1\u903b\u8f91\u7684\u6027\u80fd\u8981\u4f18\u4e8eStringBuffer\uff0c\u56e0\u4e3aStringBuffer\u65b9\u6cd5\u4e2d\u7684synchronized\u9501\u592a\u91cd\u4e86\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">==\u548cequals\u7684\u533a\u522b<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>==\n<ul class=\"wp-block-list\">\n<li>\u76f8\u540c\u57fa\u672c\u6570\u636e\u7c7b\u578b\u6bd4\u8f83\u65f6\uff0c\u662f\u57fa\u672c\u6570\u636e\u7c7b\u578b\u503c\u7684\u6bd4\u8f83\u3002<\/li>\n\n\n\n<li>\u76f8\u540c\u7684\u5f15\u7528\u7c7b\u578b\u6bd4\u8f83\u65f6\uff0c\u662f\u5f15\u7528\u5bf9\u8c61\u5730\u5740\u7684\u6bd4\u8f83\uff0c\u5373\u662f\u5426\u662f\u6307\u5411\u540c\u4e00\u5757\u5185\u5b58\u5730\u5740\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>equals\n<ul class=\"wp-block-list\">\n<li>\u9ed8\u8ba4\u60c5\u51b5\uff08\u6ca1\u6709\u91cd\u5199equals\u65b9\u6cd5\uff09\u4e0b\u662f\u6bd4\u8f83\u4e24\u5bf9\u8c61\u7684\u5730\u5740\uff0c\u76f8\u5f53\u4e8e==\uff1b\u57fa\u672c\u7c7b\u578b\u7684\u5305\u88c5\u7c7b\u9664\u5916\uff0c\u5b83\u4eec\u4f1a\u8fdb\u884c\u62c6\u7bb1\u5e76\u6bd4\u8f83\u5305\u88c5\u7684\u57fa\u672c\u6570\u636e\u7c7b\u578b\u7684\u503c\uff1bString\u7c7b\u91cd\u5199\u4e86equals\u65b9\u6cd5\uff0c\u4f1a\u5148\u6bd4\u8f83\u4e24\u4e2aString\u5bf9\u8c61\u5730\u5740\u662f\u5426\u76f8\u540c\uff0c\u5982\u679c\u4e0d\u76f8\u540c\uff0c\u518d\u6bd4\u8f83\u5b57\u7b26\u4e32\u503c\u662f\u5426\u5b8c\u5168\u4e00\u6837\uff0c\u4e00\u6837\u5219\u8fd4\u56detrue\uff0c\u5426\u5219\u8fd4\u56defalse\u3002<\/li>\n\n\n\n<li>\u91cd\u5199equals\u65b9\u6cd5\u540e\uff0c\u4f1a\u6839\u636e\u91cd\u5199\u903b\u8f91\u8fdb\u884c\u7ed3\u679c\u8fd4\u56de\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>@Getter\n@Setter\n@AllArgsConstructor\n@NoArgsConstructor\npublic class User {\n    private String name;\n    private Integer age;\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class EqualsDemo {\n    public static void main(String&#91;] args) {\n        String s1 = \"11\";\n        String s2 = \"11\";\n        System.out.println(s1 == s2);  \/\/ true\n        System.out.println(s1.equals(s2));  \/\/ true\n\n        Integer i1 = 1;\n        Integer i2 = 1;\n        System.out.println(i1 == i2);  \/\/ true\n        System.out.println(i1.equals(i2));  \/\/ true\n\n        User u1 = new User(s1, i1);\n        User u2 = new User(s2, i2);\n        System.out.println(u1 == u2); \/\/ false\n        System.out.println(u1.equals(u2)); \/\/ \u4e3a\u91cd\u65b0equals\u5219\u4e3afalse\uff0c\u91cd\u5199equals\u540e\u89c6\u903b\u8f91\u800c\u5b9a\n\n        int&#91;] a = new int&#91;9];\n        int&#91;] b = a;\n        System.out.println(a == b);\n    }\n}<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e3a\u4ec0\u4e48\u91cd\u5199equals\u5c31\u4e00\u5b9a\u8981\u91cd\u5199hashcode\u65b9\u6cd5<\/h2>\n\n\n\n<p>\u5148\u6765\u8bf4\u8bf4equals\u65b9\u6cd5\u7684\u4f5c\u7528\uff0cequals\u65b9\u6cd5\u672c\u610f\u662f\u4e3a\u4e86\u6bd4\u8f83\u4e24\u4e2a\u5bf9\u8c61\u903b\u8f91\u4e0a\u662f\u5426\u76f8\u540c\uff08\u76f8\u7b49\uff09\uff0c\u6bd4\u5982\u5206\u522bnew\u4e24\u4e2a\u503c\u4e3a&#8221;11&#8243;\u7684String\u5bf9\u8c61\uff0c\u867d\u7136\u5176\u662f\u4e0d\u540c\u7684\u4e24\u4e2a\u5185\u5b58\u5bf9\u8c61\u5185\u5b58\u5730\u5740\u4e0d\u540c\uff0c\u4f46\u662f\u903b\u8f91\u4e0a\u8fd9\u4e24\u4e2a\u5bf9\u8c61\u662f\u76f8\u540c\u7684\uff0c\u5f53\u7528equals\u6bd4\u8f83\u65f6\uff0c\u8fd4\u56de\u4e3atrue\u3002<br>hashcode\u5728hashmap\u4e2d\u548cequals\u8d77\u5230\u7684\u4f5c\u7528\u76f8\u540c\uff0c\u662f\u7528\u6765\u5224\u65adhashmap\u4e2d\u4e24\u4e2a\u5bf9\u8c61\u662f\u5426\u903b\u8f91\u76f8\u7b49\u3002hashcode\u65b9\u6cd5\u5728\u5bf9\u8c61\u6dfb\u52a0\u5230map\u7b49\u6570\u636e\u7ed3\u6784\u65f6\u4f1a\u8c03\u7528\uff0c\u7528\u6765\u8ba1\u7b97hash\u503c\uff0c\u5e76\u6839\u636ehash\u503c\u63d2\u5165\u5230\u5bf9\u5e94\u6570\u636e\u7ed3\u6784\u4e2d\uff0c\u5982\u679cequals\u5224\u65ad\u4f46\u662fhash\u503c\u4e0d\u540c\uff0c\u5c31\u4f1a\u903b\u8f91\u4e0a\u76f8\u7b49\u7684\u6570\u636e\u64cd\u4f5c\u7684\u662f\u4e0d\u540c\u7684value\u503c\u3002\u4e3e\u4f8b\u6765\u8bf4\uff0c\u6211\u4eec\u73b0\u5728\u4ee5String\u4e3a\u4f8b\uff0c\u5982\u679c\u540d\u5b57\u4e3a&#8221;\u5f20\u4e09&#8221;\u7684\u540c\u5b66\u53c2\u4e0e\u4e86\u73ed\u957f\u7ade\u9009\u6295\u7968\uff0c\u800c\u6295\u7968\u65f6\u9ed8\u8ba4\u540d\u5b57\u76f8\u540c\u5c31\u662f\u540c\u4e00\u4e2a\u4eba\uff0c\u5982\u679c\u73b0\u5728\u57fa\u4e8e&#8221;\u5f20\u4e09&#8221;\u5b57\u7b26\u4e32\u521b\u5efa\u4e86\u591a\u4e2aString\u5bf9\u8c61\u8fdb\u884c\u4e86\u6295\u7968\uff0c\u8fd9\u4e9b\u6295\u7968\u7406\u5e94\u5f52\u7968\u5230\u540c\u4e00\u4e2a\u4eba\u8eab\u4e0a\uff0c\u4f46\u662f\u5982\u679c\u540d\u5b57\u76f8\u540c\u4f46hashcode\u4e0d\u540c\u5c31\u4f1a\u51fa\u73b0\u6700\u540e\u53d6\u51fa\u7684\u5f52\u7968\u7ed3\u679c\u6bd4\u5b9e\u9645\u4e0a\u5c11\u7684\u60c5\u51b5\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>@Getter\n@Setter\n@AllArgsConstructor\n@NoArgsConstructor\npublic class User {\n    private String name;\n    private Integer age;\n\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) return true;\n        if (o == null || getClass() != o.getClass()) return false;\n        User user = (User) o;\n        return Objects.equals(name, user.name) &amp;&amp; Objects.equals(age, user.age);\n    }\n\n    @Override\n    public int hashCode() {\n        return Objects.hash(UUID.randomUUID());\n    }\n}<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>public class HashMapDemo {\n    public static void main(String&#91;] args) {\n        Map&lt;String, Integer&gt; map = new HashMap&lt;&gt;();\n        map.put(new String(\"\u5f20\u4e09\"), 1);\n        map.put(new String(\"\u5f20\u4e09\"), map.get(new String(\"\u5f20\u4e09\")) + 1);\n        System.out.println(map.get(new String(\"\u5f20\u4e09\"))); \/\/ 2\n\n        Map&lt;User, Integer&gt; userMap = new HashMap&lt;&gt;();\n        User zhangsan = new User(\"\u5f20\u4e09\", 20);\n        User zhangsan2 = new User(\"\u5f20\u4e09\", 20);\n        userMap.put(zhangsan, 1);\n        userMap.put(zhangsan2, userMap.getOrDefault(zhangsan2, 0) + 1);\n        System.out.println(userMap.getOrDefault(zhangsan, 0));\n    }\n}<\/code><\/pre>\n\n\n\n<p>hasCode\u53d6\u968f\u673a\u6570\uff0c\u8fd9\u65f6\u7ed3\u679c\u4e3a0\uff0c\u4e0e\u903b\u8f91\u76f8\u6096\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>@Getter\n@Setter\n@AllArgsConstructor\n@NoArgsConstructor\npublic class User {\n    private String name;\n    private Integer age;\n\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) return true;\n        if (o == null || getClass() != o.getClass()) return false;\n        User user = (User) o;\n        return Objects.equals(name, user.name) &amp;&amp; Objects.equals(age, user.age);\n    }\n\n    @Override\n    public int hashCode() {\n        return Objects.hash(name, age);\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u4fee\u6539hashCode\u903b\u8f91\uff0c\u53d6name\u548cage\u7684hash\u503c\uff0c\u8fd9\u6837\u4e0a\u9762\u4ee3\u7801\u8fd0\u884c\u7ed3\u679c\u5c31\u662f2\uff0c\u7b26\u5408\u903b\u8f91\u3002<\/p>\n\n\n\n<p>\u603b\u7ed3\uff1a\u91cd\u5199equals\u7684\u540c\u65f6\u91cd\u5199hashCode\u65b9\u6cd5\u5c31\u662f\u4e3a\u4e86\u786e\u4fddhashMap\u7b49\u9700\u8981\u8fdb\u884c\u8ba1\u7b97hash\u503c\u7684\u6570\u636e\u7ed3\u6784\u80fd\u591f\u88ab\u6b63\u786e\u4f7f\u7528\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u53d7\u68c0\u5f02\u5e38\u548c\u975e\u53d7\u68c0\u5f02\u5e38<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d7\u68c0\u5f02\u5e38\u3002\n<ul class=\"wp-block-list\">\n<li>\u5b9a\u4e49\u3002\u53d7\u68c0\u5f02\u5e38\u662f\u5728\u7f16\u8bd1\u524d\u5f3a\u5236\u68c0\u67e5\u7684\u5f02\u5e38\u3002\u5982\u679c\u4ee3\u7801\u4e2d\u5b58\u5728\u53ef\u80fd\u629b\u51fa\u53d7\u68c0\u5f02\u5e38\u7684\u4ee3\u7801\uff0c\u4e14\u6ca1\u6709\u88ab\u6b63\u786e\u7684\u5904\u7406\uff08try-catch\u6216\u5728\u65b9\u6cd5\u7b7e\u540d\u5904\u629b\u51fathrows\u629b\u51fa\uff09\uff0c\u5219\u4f1a\u5728\u7f16\u8bd1\u9636\u6bb5\u62a5\u9519\uff0c\u5bfc\u81f4\u7a0b\u5e8f\u65e0\u6cd5\u901a\u8fc7\u7f16\u8bd1\u3002<\/li>\n\n\n\n<li>\u5178\u578b\u53d7\u68c0\u5f02\u5e38\u3002IOException\u3001InterruptedException<\/li>\n\n\n\n<li>\u5904\u7406\u65b9\u6cd5\u3002try-catch\u6216\u5728\u65b9\u6cd5\u7b7e\u540d\u5904\u629b\u51fathrows\u629b\u51fa\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u975e\u53d7\u68c0\u65f6\u5f02\u5e38\u3002\u5305\u62ecRuntimeException\u548c\u5b83\u7684\u5b50\u7c7b\u3001Error\u548c\u5b83\u7684\u5b50\u7c7b\u3002\n<ul class=\"wp-block-list\">\n<li>\u5b9a\u4e49\u3002\u4e0d\u9700\u8981\u5f3a\u5236\u5904\u7406\uff0c\u901a\u5e38\u7531\u7f16\u7a0b\u9519\u8bef\u5f15\u8d77\u3002<\/li>\n\n\n\n<li>\u5178\u578b\u975e\u53d7\u68c0\u5f02\u5e38\u3002ArrayIndexOutOfBoundsException\u3001NullPointerException\u7b49<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">JDK\u52a8\u6001\u4ee3\u7406\u4e3a\u4ec0\u4e48\u53ea\u80fd\u4ee3\u7406\u6709\u63a5\u53e3\u7684\u7c7b<\/h2>\n\n\n\n<p>\u8fd9\u662f\u7531JDK\u52a8\u6001\u4ee3\u7406\u7684\u8bbe\u8ba1\u673a\u5236\u51b3\u5b9a\u7684\u3002<\/p>\n\n\n\n<p>java\u4e2d\u52a8\u6001\u4ee3\u7406\u662f\u901a\u8fc7Proxy.newProxyInstance\u65b9\u6cd5\u5b9e\u73b0\u7684\uff0c\u9700\u8981\u4f20\u5165\u5b9e\u73b0\u7c7b\u7684\u63a5\u53e3\u7c7b\uff0c\u4e4b\u6240\u4ee5\u4f20\u5165\u63a5\u53e3\u4e0d\u4f20\u5165\u7c7b\u662f\u7531JDK\u52a8\u6001\u4ee3\u7406\u7684\u5e95\u5c42\u5b9e\u73b0\u51b3\u5b9a\u7684\u3002<\/p>\n\n\n\n<p>\u5728\u7a0b\u5e8f\u8fd0\u884c\u671f\u95f4JDK\u52a8\u6001\u4ee3\u7406\u4f1a\u52a8\u6001\u751f\u6210\u4e00\u4e2a$proxy\u7684\u7c7b\uff0c\u8be5\u7c7b\u7ee7\u627f\u4e86Proxy\u7236\u7c7b\uff0c\u540c\u65f6\u8fd8\u4f1a\u5b9e\u73b0\u88ab\u4ee3\u7406\u7c7b\u7684\u63a5\u53e3\uff0cjava\u4e2d\u662f\u4e0d\u652f\u6301\u591a\u7ee7\u627f\u7684\uff0c\u800c\u52a8\u6001\u4ee3\u7406\u7c7b\u5fc5\u987b\u7ee7\u627fProxy\u7c7b\uff0c\u6240\u4ee5\u5bfc\u81f4JDK\u52a8\u6001\u4ee3\u7406\u7c7b\u53ea\u80fd\u4ee3\u7406\u63a5\u53e3\u800c\u4e0d\u80fd\u4ee3\u7406\u5b9e\u73b0\u7c7b\u3002<\/p>\n\n\n\n<p>\u52a8\u6001\u4ee3\u7406\u5b9e\u73b0\u9700\u6c42\u5c31\u662f\u5bf9\u539f\u59cb\u5b9e\u73b0\u7684\u62e6\u622a\uff0c\u7136\u540e\u5728\u5b9e\u73b0\u4e0a\u505a\u529f\u80fd\u589e\u5f3a\u6216\u6269\u5c55\u3002\u5b9e\u9645\u5f00\u53d1\u4e2d\u90fd\u662f\u9762\u5411\u63a5\u53e3\u5f00\u53d1\uff0c\u6240\u4ee5JDK\u52a8\u6001\u4ee3\u7406\u662f\u4e0e\u5927\u90e8\u5206\u5b9e\u9645\u5f00\u53d1\u573a\u666f\u543b\u5408\u7684\u3002\u5982\u679c\u6709\u5b9e\u73b0\u7c7b\u7684\u52a8\u6001\u4ee3\u7406\u573a\u666f\u6211\u4eec\u4e5f\u80fd\u7528CGLIB\u7ec4\u4ef6\u5b9e\u73b0\uff0c\u5b83\u4f1a\u52a8\u6001\u751f\u6210\u4e00\u4e2a\u4ee3\u7406\u7c7b\u7684\u5b50\u7c7b\uff0c\u5b50\u7c7b\u91cd\u5199\u7236\u7c7b\u4e2d\u975efinal\u7684\u65b9\u6cd5\uff0c\u5728\u5b50\u7c7b\u4e2d\u62e6\u622a\u7236\u7c7b\u6240\u6709\u65b9\u6cd5\u7684\u8c03\u7528\uff0c\u4ece\u800c\u5b9e\u73b0\u52a8\u6001\u4ee3\u7406\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">HashMap\u662f\u5982\u4f55\u89e3\u51b3hash\u51b2\u7a81\u7684\uff1f<\/h2>\n\n\n\n<p>\u7ed3\u8bba\uff1aHashMap\u91c7\u7528\u4e86\u62c9\u94fe\u6cd5\u89e3\u51b3hash\u51b2\u7a81\u95ee\u9898\u3002<\/p>\n\n\n\n<p>HashMap\u5e95\u5c42\u662f\u7531\u6570\u7ec4\u5b9e\u73b0\u7684\uff0c\u521d\u59cb\u5bb9\u91cf\u4e3a16\uff0c\u5f53\u6dfb\u52a0\u5143\u7d20\u65f6\uff0c\u4f1a\u6839\u636ekey\u503c\u8ba1\u7b97hash\u503c\uff0c\u518d\u53d6\u6a21\u5f97\u5230\u7d22\u5f15\u503c\uff0c\u5e76\u5b58\u50a8\u5728\u6570\u7ec4\u5bf9\u5e94\u7d22\u5f15\u4f4d\u7f6e\uff0c\u8fd9\u65f6\u5c31\u53ef\u80fd\u4f1a\u53d1\u751fhash\u51b2\u7a81\uff0c\u800chashMap\u7684\u8bbe\u8ba1\u8005\u91c7\u7528\u7684\u662f\u62c9\u94fe\u6cd5\u8fdb\u884c\u89e3\u51b3\u7684\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u94fe\u8868\u3002\u5728hash\u51b2\u7a81\u521d\u671f\u4f7f\u7528\u7684\u662f\u94fe\u8868\u5b58\u50a8\u3002<\/li>\n\n\n\n<li>\u7ea2\u9ed1\u6811\u3002\u5728\u94fe\u8868\u8fc7\u957f\u65f6\uff0c\u4f1a\u964d\u4f4e\u6570\u636e\u68c0\u7d22\u6548\u7387\uff0c\u4e3a\u4e86\u65f6\u95f4\u590d\u6742\u5ea6\uff0c\u5f53\u94fe\u8868\u957f\u5ea6\u5927\u4e8e8\u65f6\u91c7\u7528\u7ea2\u9ed1\u6811\u7ed3\u6784\u5b58\u50a8\u3002<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u96f6\u62f7\u8d1d\u662f\u4ec0\u4e48\uff1f<\/h2>\n\n\n\n<p>\u96f6\u62f7\u8d1d\u662f\u4e00\u79cd\u8ba1\u7b97\u673a\u4f20\u5728\u8f93\u6587\u4ef6\u65f6\u7684I\/O\u4f18\u5316\u6280\u672f\u3002<\/p>\n\n\n\n<p>\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u5982\u679c\u6211\u4eec\u60f3\u628a\u78c1\u76d8\u4e2d\u7684\u6587\u4ef6\u4f20\u8f93\u5230\u8fdc\u7a0b\u670d\u52a1\u5668\u4e0a\uff0c\u9700\u8981\u7ecf\u8fc7\u4ee5\u4e0b\u51e0\u4e2a\u8fc7\u7a0b\u3002<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5c06\u78c1\u76d8\u4e2d\u7684\u6587\u4ef6\u62f7\u8d1d\u5230\u5185\u6838\u7f13\u51b2\u533a\u4e2d\u3002<\/li>\n\n\n\n<li>\u5c06\u5185\u6838\u7f13\u51b2\u533a\u4e2d\u7684\u5185\u5bb9\u62f7\u8d1d\u5230\u7528\u6237\u7f13\u51b2\u533a\u4e2d\u3002<\/li>\n\n\n\n<li>\u5c06\u7528\u6237\u7f13\u51b2\u533a\u4e2d\u7684\u5185\u5bb9\u62f7\u8d1d\u5230Socket buffer\u4e2d\u3002<\/li>\n\n\n\n<li>\u5c06Socket buffer\u4e2d\u7684\u5185\u5bb9\u62f7\u8d1d\u5230\u7f51\u5361\u7f13\u51b2\u533a\u3002<\/li>\n\n\n\n<li>\u7f51\u5361\u7f13\u51b2\u533a\u518d\u5c06\u6570\u636e\u4f20\u8f93\u5230\u76ee\u6807\u670d\u52a1\u5668\u4e0a\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u8fd9\u51e0\u4e2a\u6d41\u7a0b\u5b58\u57284\u6b21\u62f7\u8d1d\u64cd\u4f5c\uff0c\u4e14\u6d89\u53ca\u5230\u7528\u6237\u6001\u548c\u5185\u6838\u6001\u7684\u5207\u6362\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528\u96f6\u62f7\u8d1d\u6280\u672f\uff0c\u53ef\u4ee5\u4e0d\u7ecf\u5386\u7528\u6237\u7f13\u51b2\u533a\u7684\u6570\u636e\u62f7\u8d1d\uff0c\u76f4\u63a5\u4ece\u5185\u6838\u5c42\u9762\u5c06\u6570\u636e\u62f7\u8d1d\u5230Socket\u7f13\u51b2\u533a\u4e2d\uff0c\u8282\u7701\u4e86\u4e24\u6b21\u6570\u636e\u62f7\u8d1d\u7684\u65f6\u95f4\uff0c\u4e14\u4e0d\u7528\u7ecf\u8fc7\u7528\u6237\u6001\u5230\u5185\u6838\u6001\u7684\u5207\u6362\uff0c\u8282\u7701\u4e86\u4e0a\u4e0b\u6587\u5207\u6362\u7684\u65f6\u95f4\uff0c\u4ece\u800c\u63d0\u9ad8\u4e86\u6574\u4f53\u64cd\u4f5c\u901f\u5ea6\u3002<\/p>\n\n\n\n<p>\u96f6\u62f7\u8d1d\u5b9e\u73b0\uff1a<\/p>\n\n\n\n<p>linux\u4e2d\uff0c\u96f6\u62f7\u8d1d\u6280\u672f\u4f9d\u8d56\u4e8e\u5e95\u5c42\u7684sendfile()\u65b9\u6cd5\uff0c\u800c\u5728java\u4e2dFileChannel.transfer\u65b9\u6cd5\u7684\u5e95\u5c42\u5b9e\u73b0\u903b\u8f91\u5c31\u662fsendFile()\u65b9\u6cd5\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Integer\u4f7f\u7528\u4e0d\u5f53\u5bfc\u81f4\u7684\u751f\u4ea7\u4e8b\u6545<\/h2>\n\n\n\n<p>\u573a\u666f\uff1a\u9700\u8981\u5bf9\u5e38\u7528\u8303\u56f4\uff08-127-128\uff09Integer\u5bf9\u8c61\u8fdb\u884c==\u6bd4\u8f83\u65f6\u3002<\/p>\n\n\n\n<p>Integer\u7c7b\u91c7\u7528\u4e86\u4eab\u5143\u6a21\u5f0f\u7684\u8bbe\u8ba1\uff0c\u5f53\u901a\u8fc7valueOf\u521b\u5efaInteger\u5bf9\u8c61\uff0c\u4e14\u5f53\u6570\u503c\u8303\u56f4\u5728-127-128\u4e4b\u95f4\u76f8\u540c\u503c\u5bf9\u8c61\u8fdb\u884c\u6bd4\u8f83\u65f6\uff0c\u4f1a\u8fd4\u56detrue\uff0c\u4f46\u662f\u5982\u679c\u503c\u8303\u56f4\u4e0d\u5728-127-128\u4e4b\u95f4\uff0c\u5219\u4f1a\u8fd4\u56defalse\u3002<\/p>\n\n\n\n<p>\u8fd9\u662f\u56e0\u4e3a\u5f53\u9996\u6b21\u4f7f\u7528Integer.valueOf\u9759\u6001\u65b9\u6cd5\u65f6\uff0c\u9759\u6001\u5185\u90e8\u7c7bIntegerCache\u4f1a\u521d\u59cb\u5316\uff0c\u5b83\u4f1a\u521b\u5efa-127-128\u4e4b\u95f4\u7684Integer\u5bf9\u8c61\u4f5c\u4e3a\u7f13\u5b58\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u5f53\u4f7f\u7528Integer.valueOf\u83b7\u53d6-127-128\u4e4b\u95f4\u7684Integer\u5bf9\u8c61\u65f6\uff0c\u4f1a\u76f4\u63a5\u4ece\u7f13\u5b58\u4e2d\u53d6\u5bf9\u5e94\u7684Integer\u5bf9\u8c61\uff0c\u800c\u4e0d\u4f1a\u91cd\u65b0\u521b\u5efa\u4e00\u4e2a\u65b0\u7684Integer\u5bf9\u8c61\u3002<\/p>\n\n\n\n<p>\u8fd9\u6837\u5728\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u83b7\u53d6\u7684Integer\u5bf9\u8c61\u4e0a\u8fdb\u884c==\u6bd4\u8f83\u65f6\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u8303\u56f4\u5728-127-128\u4e4b\u95f4\uff0c\u5219\u8fd4\u56detrue\uff0c\u8bf4\u660e\u662f\u540c\u4e00\u4e2a\u5bf9\u8c61\u3002<\/li>\n\n\n\n<li>\u5982\u679c\u8303\u56f4\u5728-127-128\u4e4b\u5916\uff0c\u5219\u8fd4\u56defalse\uff0c\u8bf4\u660e\u4e0d\u662f\u540c\u4e00\u4e2a\u5bf9\u8c61\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4ee5\u4e0b\u662f\u4ee3\u7801\u5b9e\u73b0\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class IntegerDemo {\n    public static void main(String&#91;] args) {\n        System.out.println(Integer.valueOf(1) == Integer.valueOf(1)); \/\/ true\n        System.out.println(Integer.valueOf(129) == Integer.valueOf(129)); \/\/ false\n\n        System.out.println(Long.valueOf(1) == Long.valueOf(1)); \/\/ true\n        System.out.println(Long.valueOf(129) == Long.valueOf(129)); \/\/ false\n\n        Integer i1 = new Integer(1);\n        Integer i2 = new Integer(2);\n\n        System.out.println(i1 == i2); \/\/ false\n\n        \/\/ \u505a\u4e86\u88c5\u7bb1\u64cd\u4f5c\uff0c\u76f8\u5f53\u4e8eInteger.valueOf(100)\n        Integer i3 = 100;\n        Integer i4 = 100;\n        System.out.println(i3 == i4); \/\/ true\n    }\n}<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">HashMap\u7684hash\u65b9\u6cd5\u4e3a\u4ec0\u4e48\u8981\u53f3\u79fb16\u4f4d<\/h2>\n\n\n\n<p>\u5bf9\u539f\u6709\u54c8\u5e0c\u7801\u505a\u4e86\u4e00\u6b21\u518d\u54c8\u5e0c\uff0c\u63d0\u9ad8\u6563\u5217\u5ea6\uff0c\u964d\u4f4ehash\u51b2\u7a81\uff0c\u63d0\u5347\u68c0\u7d22\u6548\u7387\u3002<\/p>\n\n\n\n<p>\u4f20\u7edf\u53d6\u6a21\u8fd0\u7b97\u7684\u60c5\u51b5\u4e0b\uff0c\u8ba1\u7b97\u51fa\u7684hash\u503c\u4f1a\u4e0e\u6570\u7ec4\u957f\u5ea6\u8fdb\u884c\u53d6\u6a21\u8fd0\u7b97\uff0c\u5f97\u5230\u5728\u6570\u7ec4\u4e2d\u7684\u5b58\u50a8\u4f4d\u7f6e\uff0c\u8fd9\u6837\u54c8\u5e0c\u51b2\u7a81\u7684\u6982\u7387\u8f83\u9ad8\uff0c\u5143\u7d20\u4f1a\u96c6\u4e2d\u5206\u5e03\u5728\u4e00\u4e2a\u5c0f\u533a\u95f4\u4e2d\u3002<\/p>\n\n\n\n<p>\u800c\u518d\u54c8\u5e0c\u65b9\u6cd5\uff0c\u4f1a\u628ahash\u503c\u548chash\u503c\u7684\u9ad816\u4f4d\u8fdb\u884c\u5f02\u6216\u8fd0\u7b97\uff0c\u5f97\u5230\u518d\u54c8\u5e0c\u503c\uff0c\u6700\u540e\u518d\u4e0e\u6570\u7ec4\u957f\u5ea6\u8fdb\u884c\u53d6\u6a21\u8fd0\u7b97\uff0c\u8fd9\u6837\u6700\u7ec8hash\u503c\u4e5f\u4f1a\u6536\u5230\u9ad8\u4f4d\u4fe1\u606f\u7684\u5f71\u54cd\uff0c\u4ece\u800c\u63d0\u9ad8\u6563\u5217\u5ea6\uff0c\u964d\u4f4ehash\u51b2\u7a81\u7684\u6982\u7387\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">java\u53cd\u5c04\u7684\u4f18\u7f3a\u70b9<\/h2>\n\n\n\n<p>\u4f18\u70b9\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u589e\u52a0\u7a0b\u5e8f\u7075\u6d3b\u6027\uff0c\u53ef\u4ee5\u5728\u8fd0\u884c\u8fc7\u7a0b\u4e2d\u52a8\u6001\u5bf9\u7c7b\u8fdb\u884c\u4fee\u6539\u548c\u64cd\u4f5c\u3002<\/li>\n\n\n\n<li>\u63d0\u9ad8\u4ee3\u7801\u7684\u590d\u7528\u6027\uff0c\u6bd4\u5982\u52a8\u6001\u4ee3\u7406\uff0c\u5c31\u662f\u7528\u5230\u4e86\u53cd\u5c04\u6765\u5b9e\u73b0\u3002<\/li>\n\n\n\n<li>\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u8f7b\u677e\u83b7\u53d6\u4efb\u610f\u4e00\u4e2a\u7c7b\u7684\u65b9\u6cd5\u3001\u5c5e\u6027\uff0c\u5e76\u4e14\u8fd8\u80fd\u901a\u8fc7\u53cd\u5c04\u8fdb\u884c\u52a8\u6001\u8c03\u7528\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u7f3a\u70b9\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53cd\u5c04\u4f1a\u6d89\u53ca\u5230\u52a8\u6001\u7c7b\u578b\u7684\u89e3\u6790\uff0c\u6240\u4ee5JVM\u65e0\u6cd5\u5bf9\u8fd9\u4e9b\u4ee3\u7801\u8fdb\u884c\u4f18\u5316\uff0c\u5bfc\u81f4\u6027\u80fd\u8981\u6bd4\u975e\u53cd\u5c04\u8c03\u7528\u66f4\u4f4e\u3002<\/li>\n\n\n\n<li>\u4f7f\u7528\u53cd\u5c04\u4ee5\u540e\uff0c\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u4f1a\u4e0b\u964d\u3002<\/li>\n\n\n\n<li>\u53cd\u5c04\u4f1a\u7ed5\u8fc7\u8bbf\u95ee\u9650\u5236\uff0c\u4f1a\u7834\u574f\u4ee3\u7801\u7684\u5c01\u88c5\u6027\uff0c\u6bd4\u5982\u7528\u53cd\u5c04\u8c03\u7528\u5355\u4f8b\u7c7b\u7684\u6784\u9020\u65b9\u6cd5\u7834\u574f\u5355\u4f8b\u7279\u6027\u3002<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u8bbe\u8ba1\u6a21\u5f0f\u6709\u54ea\u4e9b\uff1f\u90fd\u6709\u4ec0\u4e48\u7279\u70b9\uff1f<\/h2>\n\n\n\n<p>\u6839\u636e\u8bbe\u8ba1\u76ee\u6807\u53ef\u4ee5\u5c06\u8bbe\u8ba1\u6a21\u5f0f\u5206\u4e3a\u4e09\u7c7b\uff1a<\/p>\n\n\n\n<p>\u521b\u5efa\u578b\u6a21\u5f0f\u3001\u7ed3\u6784\u578b\u6a21\u5f0f\u548c\u884c\u4e3a\u578b\u6a21\u5f0f\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u521b\u5efa\u578b\u6a21\u5f0f\u3002\u662f\u5bf9\u8c61\u521b\u5efa\u8fc7\u7a0b\u4e2d\u51fa\u73b0\u7684\u5404\u79cd\u95ee\u9898\u7684\u89e3\u51b3\u65b9\u6848\u7684\u603b\u7ed3\u3002\n<ul class=\"wp-block-list\">\n<li>\u5de5\u5382\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u5355\u4f8b\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u6784\u5efa\u5668\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u539f\u578b\u6a21\u5f0f\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u7ed3\u6784\u578b\u6a21\u5f0f\u3002\u901a\u8fc7\u7ee7\u627f\u548c\u7ec4\u5408\u65b9\u5f0f\u5b9e\u73b0\u4e0d\u540c\u7ed3\u6784\u6765\u89e3\u51b3\u5404\u79cd\u573a\u666f\u95ee\u9898\u7684\u603b\u7ed3\u3002\n<ul class=\"wp-block-list\">\n<li>\u6865\u63a5\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u9002\u914d\u5668\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u88c5\u9970\u5668\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u4ee3\u7406\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u7ec4\u5408\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u5916\u89c2\u6a21\u5f0f\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u884c\u4e3a\u6a21\u5f0f\u3002\n<ul class=\"wp-block-list\">\n<li>\u547d\u4ee4\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u89e3\u91ca\u5668\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u7b56\u7565\u6a21\u5f0f\u3002<\/li>\n\n\n\n<li>\u89c2\u5bdf\u8005\u6a21\u5f0f\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">HashMap\u4ec0\u4e48\u65f6\u5019\u6269\u5bb9\uff1f\u600e\u4e48\u6269\u5bb9\uff1f<\/h2>\n\n\n\n<h4 class=\"wp-block-heading\">\u6269\u5bb9\u65f6\u673a<\/h4>\n\n\n\n<p>\u4e00\u822c\u6765\u8bf4\u6240\u6709\u96c6\u5408\u5bb9\u5668\uff08\u4f8b\u5982list\u3001set\u7b49\uff09\u90fd\u6709\u76f8\u5e94\u7684\u6269\u5bb9\u673a\u5236\uff0c\u5b83\u4eec\u90fd\u4f1a\u5728\u5b58\u50a8\u6570\u91cf\u8fbe\u5230\u4e34\u754c\u503c\u65f6\u8fdb\u884c\u6269\u5bb9\uff0c\u5728HashMap\u4e2d\u8fd9\u4e2a\u4e34\u754c\u503c\u662f\u57fa\u4e8e\u8d1f\u8f7d\u56e0\u5b50\u548c\u5bb9\u91cf\u5927\u5c0f\u8fdb\u884c\u8ba1\u7b97\u7684\uff0c\u5177\u4f53\u7684threashold = loadFactor * capacity\uff0c\u5176\u4e2d\u8d1f\u8f7d\u56e0\u5b50\u9ed8\u8ba4\u4e3a0.75\u800cHashMap\u7684\u521d\u59cb\u5bb9\u91cf\u4e3a16\uff0c\u5c31\u662f\u5728\u5143\u7d20\u4e2a\u6570\u8fbe\u523012\u65f6\u5c31\u4f1a\u53d1\u751f\u6269\u5bb9\uff0c\u6269\u5bb9\u540e\u7684\u5927\u5c0f\u4e3a\u539f\u6709\u5bb9\u91cf\u7684\u4e24\u500d\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u5982\u4f55\u6269\u5bb9<\/h4>\n\n\n\n<p>\u6269\u5bb9\u65f6\u4f1a\u521b\u5efa\u4e00\u4e2a\u66f4\u957f\u7684\u6570\u7ec4\uff0c\u5e76\u5c06\u539f\u6709\u6570\u7ec4\u7684\u5143\u7d20\u62f7\u8d1d\u5230\u65b0\u6570\u7ec4\u4e2d\u5c31\u80fd\u5b8c\u6210\u6269\u5bb9\u4e86\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u8d1f\u8f7d\u56e0\u5b50\u4e3a\u4ec0\u4e48\u9ed8\u8ba4\u662f0.75<\/h4>\n\n\n\n<p>\u8d1f\u8f7d\u56e0\u5b50\u7684\u5927\u5c0f\u6709\u4e24\u4e2a\u5f71\u54cd\u56e0\u7d20\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>hash\u51b2\u7a81\u53d1\u751f\u7684\u6982\u7387\u3002\u5f53\u8d1f\u8f7d\u56e0\u5b50\u8fc7\u5927\u65f6\uff0chash\u51b2\u7a81\u53d1\u751f\u7684\u6982\u7387\u5c31\u4f1a\u8d8a\u5927\uff0c\u4f1a\u964d\u4f4e\u5143\u7d20\u7684\u68c0\u7d22\u6548\u7387\u3002\n<ul class=\"wp-block-list\">\n<li>\u5f53\u8d1f\u8f7d\u56e0\u5b50\u4e3a0.75\u65f6\uff0c\u94fe\u8868\u957f\u5ea6\u8fbe\u52308\u7684\u6982\u7387\u51e0\u4e4e\u4e3a\u96f6\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u7a7a\u95f4\u4f7f\u7528\u7387\u3002\u5f53\u8d1f\u8f7d\u56e0\u5b50\u8fc7\u5c0f\u65f6\uff0c\u6570\u7ec4\u7684\u7a7a\u95f4\u4f7f\u7528\u7387\u8f83\u4f4e\uff0c\u4f1a\u6d6a\u8d39\u5927\u91cf\u5185\u5b58\u7a7a\u95f4\u3002<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">\u5f3a\u5f15\u7528\u3001\u5f31\u5f15\u7528\u3001\u8f6f\u5f15\u7528\u548c\u865a\u5f15\u7528\u7684\u533a\u522b<\/h2>\n\n\n\n<p>\u5728java\u4e2d\uff0c\u5f3a\u5f15\u7528\u3001\u5f31\u5f15\u7528\u3001\u8f6f\u5f15\u7528\u548c\u865a\u5f15\u7528\u662f\u4e0d\u540c\u7c7b\u578b\u7684\u5f15\u7528\uff0c\u7528\u4e8e\u7ba1\u7406\u5bf9\u8c61\u7684\u751f\u547d\u5468\u671f\u3002\u5b83\u4eec\u7684\u533a\u522b\u4e3b\u8981\u5728\u4e8e\u5f15\u7528\u5bf9\u8c61\u88ab\u5783\u573e\u56de\u6536\u7684\u6761\u4ef6\u548c\u65f6\u673a\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5f3a\u5f15\u7528\u3002\u6700\u5e38\u89c1\u7684\u5f15\u7528\u7c7b\u578b\uff0c\u901a\u5e38\u901a\u8fc7\u8d4b\u503c\u64cd\u4f5c\u521b\u5efa\u3002\u5f53\u4e00\u4e2a\u5bf9\u8c61\u5177\u6709\u5f3a\u5f15\u7528\u65f6\uff0c\u5373\u4f7f\u5185\u5b58\u4e0d\u8db3\u4e5f\u4e0d\u4f1a\u56de\u6536\u3002<\/li>\n\n\n\n<li>\u8f6f\u5f15\u7528\u901a\u8fc7SoftReference\u7c7b\u6765\u8868\u793a\uff0c\u7528\u4e8e\u63cf\u8ff0\u90a3\u4e9b\u5185\u5b58\u4e0d\u662f\u5fc5\u9700\u4f46\u4ecd\u7136\u6709\u7528\u7684\u5bf9\u8c61\u3002\u5f53\u5185\u5b58\u4e0d\u8db3\u65f6\u624d\u4f1a\u56de\u6536\u3002\u4e00\u822c\u7528\u4e8e\u5b9e\u73b0\u9ad8\u901f\u7f13\u5b58\u7b49\u573a\u666f\u3002<\/li>\n\n\n\n<li>\u5f31\u5f15\u7528\u901a\u8fc7WeakReference\u7c7b\u6765\u8868\u793a\u3002\u8f6f\u5f15\u7528\u5e76\u4e0d\u4f1a\u963b\u6b62\u5bf9\u8c61\u88ab\u5783\u573e\u56de\u6536\u3002\u5982\u679c\u4e00\u4e2a\u5bf9\u8c61\u53ea\u6709\u5f31\u5f15\u7528\u6307\u5411\u5b83\uff0c\u90a3\u4e48\u5783\u573e\u56de\u6536\u5668\u4f1a\u5728\u4e0b\u4e00\u6b21\u8fd0\u884c\u65f6\u56de\u6536\u8be5\u5bf9\u8c61\u3002\u5f31\u5f15\u7528\u901a\u5e38\u7528\u4e8e\u6784\u5efa\u53ef\u4ee5\u5728\u5bf9\u8c61\u4e0d\u518d\u88ab\u5f3a\u5f15\u7528\u65f6\u81ea\u52a8\u91ca\u653e\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5982\u54c8\u5e0c\u8868\u7684\u952e\u3002<\/li>\n\n\n\n<li>\u865a\u5f15\u7528\u901a\u8fc7PhantomReference\u7c7b\u6765\u8868\u793a\u3002\u865a\u5f15\u7528\u7528\u4e8e\u76d1\u63a7\u5bf9\u8c61\u88ab\u5783\u573e\u56de\u6536\u7684\u60c5\u51b5\uff0c\u4f46\u672c\u8eab\u5e76\u4e0d\u963b\u6b62\u5bf9\u8c61\u88ab\u56de\u6536\u3002\u865a\u5f15\u7528\u901a\u5e38\u4e0eReferenceQueue\u4e00\u8d77\u4f7f\u7528\uff0c\u5f53\u5bf9\u8c61\u88ab\u56de\u6536\u65f6\uff0c\u865a\u5f15\u7528\u4f1a\u88ab\u653e\u5165\u5f15\u7528\u961f\u5217\u4e2d\uff0c\u4ee5\u4fbf\u5e94\u7528\u7a0b\u5e8f\u53ef\u4ee5\u4e86\u89e3\u5230\u5bf9\u8c61\u4f55\u65f6\u88ab\u56de\u6536\u3002<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">java\u6709\u54ea\u51e0\u79cd\u6587\u4ef6\u62f7\u8d1d\u65b9\u5f0f\uff1f\u54ea\u4e00\u79cd\u6700\u9ad8\u6548\uff1f<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>java.io\u5305\u4e0b\u7684\u5e93\u3002\u4f7f\u7528FileInputStream\u6765\u8bfb\u53d6\u6587\u4ef6\uff0c\u5e76\u7528FileOutputStream\u6765\u5199\u5165\u6587\u4ef6\u3002<\/li>\n\n\n\n<li>java.nio\u5305\u4e0b\u7684\u5e93\u3002transferTo\u548ctransferFrom\u6765\u5b9e\u73b0\u3002<\/li>\n\n\n\n<li>java\u6807\u51c6\u7c7b\u5e93\u63d0\u4f9b\u7684Files.copy\u5b9e\u73b0\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4f20\u7edfIO\u64cd\u4f5c\u4f1a\u8c03\u7528\u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u63d0\u4f9b\u7684IO\u63a5\u53e3read()\u548cwrite()\u65b9\u6cd5\uff0c\u5f53\u7528\u6237\u7ebf\u7a0b\u8c03\u7528read()\u65f6\uff0c\u4f1a\u629b\u51fa\u4e00\u4e2a\u5f02\u5e38\uff0c\u5c06\u6587\u4ef6\u64cd\u4f5c\u59d4\u6258\u7ed9\u5185\u6838\u7ebf\u7a0b\u8fdb\u884c\u5904\u7406\u3002\u5728\u5185\u6838\u7ebf\u7a0b\u62ff\u5230CPU\u65f6\u95f4\u7247\u540e\uff0c\u4f1a\u6355\u83b7\u8fd9\u4e2a\u5f02\u5e38\uff0c\u5e76\u4e14\u6267\u884cread()\u65b9\u6cd5\uff0c\u5c06\u78c1\u76d8\u4e2d\u7684\u6587\u4ef6\u62f7\u8d1d\u5230\u5185\u6838\u7684IO\u7f13\u51b2\u533a\u4e2d\uff0c\u7136\u540e\u5c06\u6587\u4ef6\u62f7\u8d1d\u5230jvm\u4e2d\u7684\u7528\u6237\u7f13\u51b2\u533a\u4e2d\uff0c\u8fd9\u6837\u7684\u6587\u4ef6\u8bfb\u53d6\u548c\u5199\u5165\u65b9\u5f0f\u6548\u7387\u8f83\u4f4e\u3002\u800ctransferTo()\u548ctransferFrom()\u65b9\u6cd5\u662f\u96f6\u62f7\u8d1d\u7684\u4e00\u79cd\u5b9e\u73b0\uff0c\u5b83\u8ba9\u6587\u4ef6\u62f7\u8d1d\u76f4\u63a5\u5728\u5185\u6838\u7a7a\u95f4\u4e2d\u8fdb\u884c\u64cd\u4f5c\uff0c\u907f\u514d\u4e86\u4e0d\u5fc5\u8981\u7684\u7528\u6237\u5185\u5b58\u548c\u5185\u6838\u5185\u5b58\u4e4b\u95f4\u7684\u62f7\u8d1d\u548c\u4e0a\u4e0b\u6587\u5207\u6362\uff0c\u63d0\u9ad8\u4e86\u62f7\u8d1d\u6548\u7387\uff0c\u662f\u4e09\u79cd\u4e2d\u6700\u9ad8\u6548\u7684\u4e00\u79cd\u62f7\u8d1d\u65b9\u5f0f\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e3a\u4ec0\u4e48\u963f\u91cc\u624b\u518c\u4e2d\u89c4\u5b9a\u8981\u7528\u5305\u88c5\u7c7b\u578b\u6765\u5b9a\u4e49\u5c5e\u6027\uff1f<\/h2>\n\n\n\n<p>\u6b64\u5f00\u53d1\u89c4\u8303\u4e3a\u4e86\u63d0\u9ad8\u7a0b\u5e8f\u540e\u7eed\u7684\u53ef\u7ef4\u62a4\u6027\u5e76\u907f\u514d\u4e00\u4e9b\u4f4e\u7ea7\u9519\u8bef\u800c\u63d0\u51fa\u7684\uff0c\u4e3b\u8981\u4f53\u73b0\u5728\u4ee5\u4e0b\u51e0\u4e2a\u65b9\u9762\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u9ed8\u8ba4\u503c\u95ee\u9898\u3002\u57fa\u672c\u6570\u636e\u7c7b\u578b\u6709\u5404\u81ea\u7684\u9ed8\u8ba4\u503c\uff0c\u6bd4\u5982int\u9ed8\u8ba4\u503c\u4e3a0\uff0c\u5728\u67d0\u4e9b\u573a\u666f\u4e0b0\u503c\u5e76\u4e0d\u80fd\u660e\u786e\u7684\u8868\u660e\u5c5e\u6027\u7684\u72b6\u6001\u3002\u800c\u5305\u88c5\u7c7b\u578b\u521d\u59cb\u503c\u662fnull\uff0c\u8868\u793a\u8be5\u5bf9\u8c61\u4e3a\u7a7a\uff0c\u5e76\u6ca1\u6709\u88ab\u8d4b\u8fc7\u503c\uff0c\u80fd\u66f4\u6e05\u6670\u7684\u8868\u8fbe\u5c5e\u6027\u7684\u72b6\u6001\u3002<\/li>\n\n\n\n<li>\u7279\u5b9a\u573a\u666f\u4e0b\u7684\u88c5\u7bb1\u548c\u62c6\u7bb1\u64cd\u4f5c\u5e26\u6765\u7684\u6027\u80fd\u548c\u53ef\u8bfb\u6027\u95ee\u9898\u3002\u4f7f\u7528\u5305\u88c5\u7c7b\u578b\u80fd\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u3002<\/li>\n\n\n\n<li>java\u4e2d\u7684\u8303\u578b\u53ea\u80fd\u4f7f\u7528\u5bf9\u8c61\u7c7b\u578b\u3002\u5982\u679c\u8981\u5728\u7f16\u7801\u4e2d\u4f7f\u7528\u8303\u578b\uff0c\u5c31\u5fc5\u987b\u4f7f\u7528\u57fa\u672c\u7c7b\u578b\u7684\u5305\u88c5\u7c7b\u578b\u3002<\/li>\n\n\n\n<li>\u5305\u88c5\u7c7b\u578b\u63d0\u4f9b\u4e86\u57fa\u672c\u6570\u636e\u7c7b\u578b\u4e0d\u5177\u5907\u7684\u65b9\u6cd5\uff0c\u4f8b\u5982equals()\uff0chashCode()\uff0ctoString()\u7b49\uff0c\u5728\u7279\u5b9a\u573a\u666f\u4e0b\u6bd4\u8f83\u6709\u7528\u3002<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">java\u6709\u7b26\u53f7int\u6700\u5927\u503c\u52a0\u4e00\u7b49\u4e8e\u4ec0\u4e48\uff1f<\/h2>\n\n\n\n<p>java\u6709\u7b26\u53f7\u8d1f\u6570\u7684\u8ba1\u7b97\u65b9\u5f0f\u662f\u91c7\u7528\u8865\u7801\u7684\u5f62\u5f0f\u8868\u793a\u7684\uff1a<\/p>\n\n\n\n<p>\u8f6c\u6362\u65b9\u5f0f\u4e3a\uff1a\u8d1f\u6570=\u6b63\u6570\u7684\u53cd\u7801+1<\/p>\n\n\n\n<p>\u4f8b\u5982\uff1a5 = 0000 0101\uff0c-5 = 1111 1011<\/p>\n\n\n\n<p>-5 + 1\u5f97\u5230-4\uff0c-4 = 1111 1100 \u53d6\u8865\u7801\u7684\u786e\u5c31\u662f4\u7684\u4e8c\u8fdb\u5236\u8868\u793a\uff0800000100\uff09<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">hashMap\u6269\u5bb9\u673a\u5236<\/h2>\n\n\n\n<h5 class=\"wp-block-heading\">\u4f55\u65f6\u624d\u4f1a\u89e6\u53d1\u6269\u5bb9\uff1f<\/h5>\n\n\n\n<p>\u5f53hashMap\u4e2d\u7684\u5143\u7d20\u4e2a\u6570\u5927\u4e8ethreshold\u65f6\uff0c\u800cthreshold\u53c8\u7b49\u4e8e\u6570\u7ec4\u5bb9\u91cf\u4e58\u8d1f\u8f7d\u56e0\u5b50\uff08loadFactor\uff09,loadFactor\u9ed8\u8ba4\u4e3a0.75<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u94fe\u8868\u4ec0\u4e48\u65f6\u5019\u53d8\u6210\u7ea2\u9ed1\u6811\uff1f<\/h5>\n\n\n\n<p>\u589e\u52a0\u5143\u7d20\u65f6\uff0c\u5f53\u94fe\u8868\u957f\u5ea6\u5927\u4e8e8\u65f6\u4e14\u6570\u7ec4\u957f\u5ea6\u5927\u4e8e64\u65f6\uff0c\u4f1a\u5c06\u94fe\u8868\u53d8\u6210\u7ea2\u9ed1\u6811\u6570\u636e\u7ed3\u6784<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u7ea2\u9ed1\u6811\u4ec0\u4e48\u65f6\u5019\u9000\u56de\u94fe\u8868\uff1f<\/h5>\n\n\n\n<p>\u6269\u5bb9\u65f6\uff0c\u4f1a\u5c06\u65e7\u7684\u7ea2\u9ed1\u6811\u4e2d\u7684\u5143\u7d20\u5206\u914d\u5230\u4e24\u4e2a\u6876\u4e2d\uff0c\u5982\u679c\u5176\u4e2d\u4e00\u4e2a\u6876\u7684\u5143\u7d20\u4e2a\u6570\u5c0f\u4e8e\u7b49\u4e8e6\u4e2a\u65f6\u4f1a\u9000\u56de\u5230\u94fe\u8868\u6570\u636e\u7ed3\u6784\u3002<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u6269\u5bb9\u8fc7\u7a0b<\/h5>\n\n\n\n<ol 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