{"id":589,"date":"2015-04-27T20:32:13","date_gmt":"2015-04-27T12:32:13","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=589"},"modified":"2026-08-18T12:09:31","modified_gmt":"2026-08-18T04:09:31","slug":"%e6%af%8f%e4%b8%aajava%e5%88%9d%e5%ad%a6%e8%80%85%e9%83%bd%e5%ba%94%e8%af%a5%e6%90%9e%e6%87%82%e7%9a%84%e9%97%ae%e9%a2%98","status":"publish","type":"post","link":"https:\/\/ai.zhousir.top\/?p=589","title":{"rendered":"\u6bcf\u4e2aJava\u521d\u5b66\u8005\u90fd\u5e94\u8be5\u641e\u61c2\u7684\u95ee\u9898"},"content":{"rendered":"
\n

\u4e0b\u9762\u8fd9\u7ec4\u95ee\u9898\uff0c\u6bcf\u4e2a\u5b66 Java \u7684\u4eba\u90fd\u5e94\u8be5\u641e\u61c2\u3002\u5982\u679c\u53ea\u662f\u73a9\u73a9\u53ef\u4ee5\u8df3\u8fc7\uff1b\u82e5\u81ea\u4ee5\u4e3a\u8fc7\u4e86\u5165\u95e8\u3001\u5374\u7b54\u4e0d\u5229\u843d\uff0c\u4e0d\u59a8\u628a\u81ea\u5df1\u91cd\u65b0\u7b97\u4f5c\u521d\u5b66\u8005<\/strong>\u3002<\/p>\n

\u6838\u5fc3\u5176\u5b9e\u5c31\u51e0\u4ef6\u4e8b\uff1a\u5f15\u7528\u6307\u5411\u5bf9\u8c61\u3001==<\/code> \u6bd4\u7684\u662f\u53d8\u91cf\u91cc\u7684\u503c\u3001String<\/code> \u4e0d\u53ef\u53d8\u3001final<\/code> \u9501\u7684\u662f\u5f15\u7528\u800c\u4e0d\u662f\u5bf9\u8c61\u72b6\u6001\u3002<\/p>\n

<\/p>\n

\u4e00\u3001\u6211\u58f0\u660e\u4e86\u4ec0\u4e48\uff1f<\/h2>\n
String s = \"Hello world!\";<\/code><\/pre>\n
\u5f88\u591a\u4eba\u4f1a\u8bf4\uff1a\u58f0\u660e\u4e86\u4e00\u4e2a\u5185\u5bb9\u662f Hello world! \u7684 String\u3002\u66f4\u51c6\u786e\u7684\u8bf4\u6cd5\u662f\uff1a\u58f0\u660e\u4e86\u4e00\u4e2a\u540d\u53eb s<\/code>\u3001\u53ea\u80fd\u6307\u5411 String<\/code> \u7684\u5f15\u7528<\/strong>\uff0c\u5f53\u524d\u6307\u5411\u90a3\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\u3002\u5e76\u6ca1\u6709\u201c\u58f0\u660e\u4e00\u4e2a String \u5bf9\u8c61\u201d\uff0c\u53ea\u662f\u58f0\u660e\u4e86\u5f15\u7528\u53d8\u91cf\u3002<\/p>\n
\u82e5\u518d\u5199 String string = s;<\/code>\uff0c\u53ea\u662f\u591a\u4e86\u4e00\u4e2a\u5f15\u7528 string<\/code>\uff0c\u4e0d\u4f1a<\/strong>\u4ea7\u751f\u7b2c\u4e8c\u4e2a\u5bf9\u8c61\uff0c\u4e24\u4e2a\u5f15\u7528\u6307\u5411\u540c\u4e00\u4efd\u5185\u5bb9\u3002<\/p>\n
\u4e8c\u3001== \u548c equals \u6709\u4ec0\u4e48\u533a\u522b\uff1f<\/h2>\n
==<\/code> \u4e13\u95e8\u6bd4\u8f83\u53d8\u91cf\u91cc\u5b58\u7684\u503c<\/strong>\u662f\u5426\u76f8\u7b49\u3002\u57fa\u672c\u7c7b\u578b\u597d\u7406\u89e3\uff1a<\/p>\n
int a = 10;\nint b = 10;\n\/\/ a == b \u4e3a true<\/code><\/pre>\n
\u5bf9\u8c61\u5c31\u5bb9\u6613\u6655\uff1a<\/p>\n
String a = new String(\"foo\");\n        String b = new String(\"foo\");\n        \/\/ a == b \u4e3a false<\/code><\/pre>\n
\u5bf9\u8c61\u53d8\u91cf\u662f\u5f15\u7528\uff0c\u503c\u662f\u5185\u5b58\u5730\u5740\u3002\u4e24\u6b21 new<\/code> \u5f97\u5230\u4e24\u5757\u4e0d\u540c\u5730\u5740\uff0c\u6240\u4ee5 ==<\/code> \u662f false\u3002\u5185\u5bb9\u90fd\u662f foo\uff0c\u90a3\u662f equals<\/code> \u8be5\u7ba1\u7684\u4e8b\u3002<\/p>\n
Object<\/code> \u9ed8\u8ba4\u7684 equals<\/code> \u5176\u5b9e\u5c31\u662f ==<\/code>\uff1a<\/p>\n
boolean equals(Object o) {\n    return this == o;\n}<\/code><\/pre>\n
\u81ea\u5df1\u7684\u7c7b\u82e5\u4e0d\u8986\u76d6 equals<\/code>\uff0c\u7ed3\u679c\u5c31\u548c ==<\/code> \u4e00\u6837\u3002\u6781\u7aef\u5b9e\u73b0\u751a\u81f3\u53ef\u4ee5\u6c38\u8fdc\u8fd4\u56de true\uff1a<\/p>\n
class Monster {\n    private String content;\n    boolean equals(Object another) {\n        return true;\n    }\n}<\/code><\/pre>\n
\u7528 equals<\/code> \u6216 HashSet \/ HashMap \/ Hashtable \u4e4b\u524d\uff0c\u5148\u770b\u8fd9\u4e2a\u7c7b\u7684 equals \u5951\u7ea6\uff0c\u522b\u60f3\u5f53\u7136\u3002<\/p>\n\n\n\n\n\n\n
\u6bd4\u8f83<\/th>\n\u6bd4\u4ec0\u4e48<\/th>\n\u5178\u578b\u7ed3\u679c<\/th>\n<\/tr>\n<\/thead>\n
==<\/code><\/td>\n\u53d8\u91cf\u91cc\u7684\u503c\uff08\u57fa\u672c\u7c7b\u578b\u662f\u6570\u503c\uff0c\u5bf9\u8c61\u662f\u5730\u5740\uff09<\/td>\nnew String(\"foo\")<\/code> \u4e24\u6b21\uff0c\u4e3a false<\/td>\n<\/tr>\n
equals<\/code><\/td>\n\u7531\u7c7b\u4f5c\u8005\u5b9a\u4e49\u7684\u201c\u5185\u5bb9\u662f\u5426\u76f8\u7b49\u201d<\/td>\nString \u6bd4\u5b57\u7b26\u5e8f\u5217\uff1b\u672a\u8986\u76d6\u5219\u7b49\u540c ==<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u4e09\u3001String \u5230\u5e95\u53d8\u4e86\u6ca1\u6709\uff1f<\/h2>\n
\u6ca1\u6709\u3002String<\/code> \u88ab\u8bbe\u8ba1\u6210\u4e0d\u53ef\u53d8<\/strong>\uff08immutable\uff09\uff0c\u6240\u6709\u5bf9\u8c61\u90fd\u4e0d\u53ef\u6539\u3002<\/p>\n
String s = \"Hello\";\ns = s + \" world!\";<\/code><\/pre>\n
s<\/code> \u539f\u5148\u6307\u5411\u5185\u5bb9\u4e3a Hello \u7684\u5bf9\u8c61\uff1b\u505a\u5b8c +<\/code> \u4e4b\u540e\uff0cs<\/code> \u6539\u53bb\u6307\u5411\u65b0\u7684 Hello world! \u5bf9\u8c61\uff0c\u65e7\u5bf9\u8c61\u8fd8\u5728\u5185\u5b58\u91cc\uff0c\u53ea\u662f\u6ca1\u4eba\u518d\u6307\u5411\u5b83\u3002<\/p>\n
\u56e0\u6b64\u9891\u7e41\u3001\u4e0d\u53ef\u9884\u89c1\u5730\u6539\u5b57\u7b26\u4e32\u65f6\uff0c\u7528 String<\/code> \u4f1a\u5236\u9020\u5927\u91cf\u5bf9\u8c61\uff0c\u5e94\u8003\u8651 StringBuffer<\/code>\u3002\u5185\u5bb9\u76f8\u540c\u7684\u5b57\u7b26\u4e32\u4e0d\u5fc5\u6bcf\u6b21 new<\/code>\uff1a<\/p>\n
public class Demo {\n    private String s;\n    public Demo() {\n        s = \"Initial Value\";\n    }\n}<\/code><\/pre>\n
\u4e0d\u8981\u5199\u6210 s = new String(\"Initial Value\");<\/code>\u3002\u540e\u8005\u6bcf\u6b21\u90fd new\uff0c\u53c8\u6162\u53c8\u8d39\u3002\u5bf9\u5b57\u7b26\u4e32\u5e38\u91cf\uff0c\u5185\u5bb9\u76f8\u540c\u5219 Java \u89c6\u4e3a\u540c\u4e00\u4e2a String<\/code> \u5bf9\u8c61\uff1bnew<\/code> \u5219\u603b\u662f\u65b0\u5bf9\u8c61\u3002\u4e0d\u53ef\u53d8\u7c7b\u53ea\u8bfb\u3001\u5e76\u53d1\u5b89\u5168\uff0c\u4f46\u6bcf\u4e2a\u72b6\u6001\u90fd\u8981\u4e00\u4e2a\u5bf9\u8c61\uff1b\u6807\u51c6\u5e93\u540c\u65f6\u63d0\u4f9b\u53ef\u53d8\u7684 StringBuffer<\/code>\u3002<\/p>\n
\u56db\u3001final \u5230\u5e95\u4fee\u9970\u4e86\u4ec0\u4e48\uff1f<\/h2>\n
final<\/code> \u8ba9\u53d8\u91cf\u201c\u4e0d\u53d8\u201d\uff0c\u4f46\u5bf9\u8c61\u53d8\u91cf\u672c\u8d28\u662f\u5f15\u7528\uff0c\u4e8e\u662f\u6709\u4e24\u5c42\u610f\u601d\uff1a\u5f15\u7528\u672c\u8eab\u4e0d\u53d8\uff0c\u548c\u5f15\u7528\u6307\u5411\u7684\u5bf9\u8c61\u4e0d\u53d8\u3002<\/p>\n
final StringBuffer a = new StringBuffer(\"immutable\");\nfinal StringBuffer b = new StringBuffer(\"not immutable\");\na = b; \/\/ \u7f16\u8bd1\u671f\u9519\u8bef\n\nfinal StringBuffer a = new StringBuffer(\"immutable\");\na.append(\" broken!\"); \/\/ \u7f16\u8bd1\u901a\u8fc7<\/code><\/pre>\n
final<\/code> \u53ea\u9501\u5f15\u7528\u5b58\u7684\u5730\u5740\uff0c\u4e0d\u4fdd\u8bc1\u5bf9\u8c61\u5185\u90e8\u72b6\u6001\u4e0d\u53d8\u3002\u591a\u7ebf\u7a0b\u91cc\u628a\u5171\u4eab\u5bf9\u8c61\u6807\u6210 final<\/code>\uff0c\u5e76\u4e0d\u80fd\u963b\u6b62\u522b\u4eba\u6539\u5b83\u7684\u5185\u5bb9\u3002<\/p>\n
\u4e94\u3001\u5230\u5e95\u8981\u600e\u6837\u521d\u59cb\u5316\uff1f<\/h2>\n
    \n
  • \n
    \u7c7b\u7684\u5c5e\u6027\uff08\u57df\uff09\uff1aJVM \u4f1a\u81ea\u52a8\u521d\u59cb\u5316\uff1b\u6ca1\u5199\u521d\u503c\u5c31\u7528\u7c7b\u578b\u9ed8\u8ba4\u503c\u3002int<\/code> \u4e3a 0\uff0cfloat<\/code> \u4e3a 0.0f\uff0cdouble<\/code> \u4e3a 0.0\uff0cboolean<\/code> \u4e3a false\uff0cchar<\/code> \u4e3a 0\uff0clong<\/code> \u4e3a 0\uff0c\u5f15\u7528\u4e3a null<\/code>\uff08\u6570\u7ec4\u5f15\u7528\u4e5f\u662f\uff09\u3002<\/section>\n<\/li>\n
  • \n
    static<\/code> \u5c5e\u6027\u5728\u7c7b\u52a0\u8f7d\u65f6\u521d\u59cb\u5316\u4e00\u6b21\uff1b\u5b9e\u4f8b\u5c5e\u6027\u5728\u521b\u5efa\u5b9e\u4f8b\u65f6\u521d\u59cb\u5316\u3002<\/section>\n<\/li>\n
  • \n
    \u65b9\u6cd5\u91cc\u7684\u5c40\u90e8\u53d8\u91cf\u5fc5\u987b\u5148\u8d4b\u503c\u518d\u4f7f\u7528\uff1b\u53ea\u5199\u5728 if<\/code> \/ try<\/code> \u91cc\u3001\u53e6\u4e00\u5206\u652f\u6ca1\u6709\u8d4b\u503c\uff0c\u7f16\u8bd1\u5668\u4f1a\u62d2\u7edd\u3002<\/section>\n<\/li>\n
  • \n
    \u65b9\u6cd5\u53c2\u6570\u4f5c\u4e3a\u5c40\u90e8\u53d8\u91cf\uff0c\u4f20\u5165\u503c\u5c31\u662f\u521d\u503c\uff0c\u4e0d\u5fc5\u518d\u521d\u59cb\u5316\u3002<\/section>\n<\/li>\n<\/ul>\n
    \u516d\u3001instanceof \u662f\u4ec0\u4e48\uff1f<\/h2>\n
    instanceof<\/code> \u662f\u4e8c\u5143\u8fd0\u7b97\u7b26\uff0c\u4e5f\u662f\u5173\u952e\u5b57\uff1a\u6d4b\u5de6\u8fb9\u5bf9\u8c61\u662f\u4e0d\u662f\u53f3\u8fb9\u7c7b\u7684\u5b9e\u4f8b\uff0c\u8fd4\u56de boolean\u3002<\/p>\n
    String s = \"I AM an Object!\";\nboolean isObject = s instanceof Object; \/\/ true<\/code><\/pre>\n
    \u8d26\u5355\u4f8b\u5b50\u91cc\u7528\u5b83\u533a\u5206 PhoneBill<\/code> \/ GasBill<\/code> \u5f80\u5f80\u88ab\u770b\u6210\u6ca1\u5229\u7528\u597d\u591a\u6001\u3002\u66f4\u9762\u5411\u5bf9\u8c61\u7684\u505a\u6cd5\u662f\u91cd\u8f7d\u4e24\u4e2a calculate<\/code>\uff1a<\/p>\n
    public double calculate(PhoneBill bill) {\n    \/\/ \u8ba1\u7b97\u7535\u8bdd\u8d26\u5355\n}\npublic double calculate(GasBill bill) {\n    \/\/ \u8ba1\u7b97\u71c3\u6c14\u8d26\u5355\n}<\/code><\/pre>\n
    \u7edd\u5927\u591a\u6570\u60c5\u51b5\u4e0d\u63a8\u8350\u9760 instanceof<\/code> \u5206\u652f\uff0c\u5e94\u4f18\u5148\u7528\u591a\u6001\u3002<\/p>\n
    \n
    \u4e00\u53e5\u8bdd\u603b\u7ed3\uff1a\u58f0\u660e\u7684\u662f\u5f15\u7528\u4e0d\u662f\u5bf9\u8c61\uff1b== \u6bd4\u5730\u5740\u3001equals \u6bd4\u5185\u5bb9\uff1bString \u4e0d\u53ef\u53d8\uff1bfinal \u9501\u5f15\u7528\u4e0d\u9501\u72b6\u6001\u3002<\/strong><\/p>\n<\/blockquote>\n<\/section>\n","protected":false},"excerpt":{"rendered":"
    \u4e0b\u9762\u8fd9\u7ec4\u95ee\u9898\uff0c\u6bcf\u4e2a\u5b66 Java \u7684\u4eba\u90fd\u5e94\u8be5\u641e\u61c2\u3002\u5982\u679c\u53ea\u662f\u73a9\u73a9\u53ef\u4ee5\u8df3\u8fc7\uff1b\u82e5\u81ea\u4ee5\u4e3a\u8fc7\u4e86\u5165\u95e8\u3001\u5374\u7b54\u4e0d\u5229\u843d\uff0c\u4e0d\u59a8\u628a\u81ea\u5df1 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[46],"tags":[43,140],"_links":{"self":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/589"}],"collection":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=589"}],"version-history":[{"count":3,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/589\/revisions"}],"predecessor-version":[{"id":592,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/589\/revisions\/592"}],"wp:attachment":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=589"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=589"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=589"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}