{"id":203348,"date":"2025-05-22T12:12:38","date_gmt":"2025-05-22T04:12:38","guid":{"rendered":"https:\/\/server.hk\/cnblog\/203348\/"},"modified":"2025-05-22T12:12:38","modified_gmt":"2025-05-22T04:12:38","slug":"%e5%a4%9a%e6%80%81%e6%80%a7%ef%bc%9ajava-%e4%b8%ad%e7%9a%84%e8%a7%a3%e7%a0%81%e6%96%b9%e6%b3%95%e9%87%8d%e5%86%99","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/203348\/","title":{"rendered":"\u591a\u6001\u6027\uff1aJava \u4e2d\u7684\u89e3\u7801\u65b9\u6cd5\u91cd\u5199"},"content":{"rendered":"

<\/b> <\/p>\n

\u591a\u6001\u6027\uff1aJava \u4e2d\u7684\u89e3\u7801\u65b9\u6cd5\u91cd\u5199<\/h1>\n

<\/i>\u6536\u85cf<\/span> <\/p>\n

\u4ece\u73b0\u5728\u5f00\u59cb\uff0c\u6211\u4eec\u8981\u52aa\u529b\u5b66\u4e60\u5566\uff01\u4eca\u5929\u6211\u7ed9\u5927\u5bb6\u5e26\u6765\u300a\u591a\u6001\u6027\uff1aJava \u4e2d\u7684\u89e3\u7801\u65b9\u6cd5\u91cd\u5199\u300b<\/span>\uff0c\u611f\u5174\u8da3\u7684\u670b\u53cb\u8bf7\u7ee7\u7eed\u770b\u4e0b\u53bb\u5427\uff01\u4e0b\u6587\u4e2d\u7684\u5185\u5bb9\u6211\u4eec\u4e3b\u8981\u4f1a\u6d89\u53ca\u5230<\/span>\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u5728\u9605\u8bfb\u672c\u6587\u8fc7\u7a0b\u4e2d\u6709\u9047\u5230\u4e0d\u6e05\u695a\u7684\u5730\u65b9\uff0c\u6b22\u8fce\u7559\u8a00\u5440\uff01\u6211\u4eec\u4e00\u8d77\u8ba8\u8bba\uff0c\u4e00\u8d77\u5b66\u4e60\uff01<\/p>\n

<\/p>\n

\u65b9\u6cd5\u91cd\u5199<\/strong>\u662fjava\u4e2d\u591a\u6001\u6027\u7684\u6838\u5fc3\u6982\u5ff5\u4e4b\u4e00\uff0c\u5141\u8bb8\u5b50\u7c7b\u63d0\u4f9b\u5176\u8d85\u7c7b\u4e2d\u5df2\u5b9a\u4e49\u7684\u65b9\u6cd5\u7684\u7279\u5b9a\u5b9e\u73b0\u3002\u8fd9\u4e2a\u5f3a\u5927\u7684\u529f\u80fd\u6709\u52a9\u4e8e\u5b9e\u73b0\u8fd0\u884c\u65f6\u591a\u6001\u6027<\/strong>\u5e76\u542f\u7528\u52a8\u6001\u65b9\u6cd5\u8c03\u5ea6<\/strong>\u3002\u5728\u8fd9\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u4eec\u5c06\u6df1\u5165\u7814\u7a76\u57fa\u672c\u6982\u5ff5\u3001\u89c4\u5219\u548c\u73b0\u5b9e\u4e16\u754c\u7684\u793a\u4f8b\uff0c\u4ee5\u5f7b\u5e95\u7406\u89e3\u65b9\u6cd5\u91cd\u5199<\/strong>\u3002<\/p>\n

\n

\u4ec0\u4e48\u662f\u65b9\u6cd5\u91cd\u5199\uff1f<\/strong> <\/h2>\n

\u5f53\u5b50\u7c7b\u4f7f\u7528\u76f8\u540c\u7684\u65b9\u6cd5\u7b7e\u540d<\/strong>\uff08\u76f8\u540c\u7684\u540d\u79f0\u3001\u53c2\u6570\u548c\u8fd4\u56de\u7c7b\u578b\u6216\u534f\u53d8\u8fd4\u56de\u7c7b\u578b\uff09\u4ece\u5176\u8d85\u7c7b\u91cd\u65b0\u5b9a\u4e49\u65b9\u6cd5\u65f6\uff0c\u5c31\u4f1a\u53d1\u751f\u65b9\u6cd5\u91cd\u5199\u3002\u4e0e\u5728\u7f16\u8bd1\u65f6\u89e3\u51b3\u7684\u65b9\u6cd5\u91cd\u8f7d\u4e0d\u540c\uff0c\u65b9\u6cd5\u91cd\u5199\u5b9e\u73b0\u4e86\u8fd0\u884c\u65f6\u591a\u6001\u6027<\/strong>\uff0c\u5176\u4e2d\u5b9e\u9645\u8c03\u7528\u7684\u65b9\u6cd5\u53d6\u51b3\u4e8e\u5bf9\u8c61\u7684\u8fd0\u884c\u65f6\u7c7b\u578b\u3002<\/p>\n

\n

1.\u65b9\u6cd5\u91cd\u5199\u89c4\u5219<\/strong> <\/h3>\n

1\u3002\u65b9\u6cd5\u7b7e\u540d\u4e00\u81f4\u6027\uff1a<\/strong> <\/p>\n

    \n
  • \u5b50\u7c7b\u4e2d\u7684\u65b9\u6cd5\u540d\u79f0\u548c\u53c2\u6570\u5217\u8868\u5fc5\u987b\u4e0e\u8d85\u7c7b\u4e2d\u7684\u65b9\u6cd5\u5b8c\u5168\u5339\u914d\u3002<\/li>\n<\/ul>\n

    2\u3002\u8fd4\u56de\u7c7b\u578b\u548c\u534f\u53d8\u8fd4\u56de\u7c7b\u578b\uff1a<\/strong><\/p>\n

      \n
    • \u8fd4\u56de\u7c7b\u578b\u5fc5\u987b\u76f8\u540c\u6216\u534f\u53d8\u7c7b\u578b<\/strong>\uff08\u8d85\u7c7b\u4e2d\u539f\u59cb\u8fd4\u56de\u7c7b\u578b\u7684\u5b50\u7c7b\u578b\uff09\u3002<\/li>\n<\/ul>\n

      3\u3002\u8bbf\u95ee\u4fee\u9970\u7b26\uff1a<\/strong><\/p>\n

        \n
      • \u5b50\u7c7b\u4e2d\u7684\u65b9\u6cd5\u4e0d\u80fd\u5177\u6709\u6bd4\u8d85\u7c7b\u4e2d\u7684\u65b9\u6cd5\u66f4\u4e25\u683c\u7684\u8bbf\u95ee\u7ea7\u522b\uff08\u4f8b\u5982\uff0c\u5982\u679c\u8d85\u7c7b\u65b9\u6cd5\u53d7\u4fdd\u62a4\uff0c\u5219\u5b50\u7c7b\u4e0d\u80fd\u5c06\u5176\u8bbe\u4e3a\u79c1\u6709\uff09\u3002<\/li>\n<\/ul>\n
        \n

        \u516c\u5171 > \u53d7\u4fdd\u62a4 > \u9ed8\u8ba4\uff08\u5305-\u79c1\u6709\uff09 > \u79c1\u6709<\/p>\n<\/blockquote>\n

        4\u3002\u65b9\u6cd5\u53ef\u89c1\u6027\uff1a<\/strong><\/p>\n

          \n
        • \u79c1\u6709\u65b9\u6cd5\u4e0d\u80fd\u88ab\u91cd\u5199<\/strong>\u3002\u76f8\u53cd\uff0c\u5982\u679c\u5728\u5b50\u7c7b\u4e2d\u91cd\u65b0\u5b9a\u4e49\uff0c\u5b83\u4eec\u5c06\u88ab\u89c6\u4e3a\u5168\u65b0\u7684\u65b9\u6cd5\u3002<\/li>\n<\/ul>\n

          \u793a\u4f8b\uff1a\u57fa\u672c\u65b9\u6cd5\u91cd\u5199<\/strong> <\/h3>\n
          package oops.polymorphism;\n\n\/\/ base class\npublic class methodoverridingparent {\n\n    \/\/ private methods cannot be overridden\n    private string getname() {\n        return \"hello\";\n    }\n\n    \/\/ display method to be overridden (access modifier: default)\n    void display() {\n        system.out.println(\"parent method called\");\n    }\n\n    \/\/ return type is number (parent class of integer, double, etc.)\n    public number getcount() {\n        return 20;\n    }\n}\n<\/pre>\n
          \u5728methodoverridingparent\u4e2d\uff0c\u53ea\u6709display()\u548cgetcount()\u53ef\u4ee5\u88ab\u5b50\u7c7b\u8986\u76d6\uff0c\u56e0\u4e3a\u5b83\u4eec\u53ef\u4ee5\u5728\u7236\u7c7b\u4e4b\u5916\u8bbf\u95ee\u3002\u7136\u800c\uff0cgetname() \u662f\u79c1\u6709\u7684\uff0c\u56e0\u6b64\u4e0d\u80fd\u88ab\u8986\u76d6\uff0c\u56e0\u4e3a\u5b83\u4e0d\u88ab\u5b50\u7c7b\u7ee7\u627f\u3002<\/p>\n
          \n
           2.\u5b50\u7c7b\u4e2d\u7684\u65b9\u6cd5\u91cd\u5199<\/strong> <\/h3>\n
          package oops.polymorphism;\n\npublic class methodoverridingchild extends methodoverridingparent {\n\n    \/\/ access level increased; default -> protected\n    @override\n    protected void display() {\n        system.out.println(\"child method called\");\n    }\n\n    public static void main(string[] args) {\n\n        \/\/ calling parent class method\n        methodoverridingparent parent = new methodoverridingparent();\n        parent.display(); \/\/ output: parent method called\n\n        \/\/ calling child class overridden method - runtime polymorphism\n        methodoverridingparent child = new methodoverridingchild();\n        child.display(); \/\/ output: child method called\n    }\n}\n<\/pre>\n
          \n
          \u8bf4\u660e<\/strong>\uff1a\u7531\u4e8e\u5b50\u7c7b methodoverridingchild \u4e2d\u91cd\u5199\u4e86 display()\uff0c\u56e0\u6b64\u5728 methodoverridingchild \u5b9e\u4f8b\u4e0a\u8c03\u7528 display() \u4f1a\u8c03\u7528\u5b50\u7c7b\u7684\u7248\u672c\u3002\u8fd9\u662f\u8fd0\u884c\u65f6\u591a\u6001\u6027<\/strong>\u7684\u5b9e\u9645\u5e94\u7528\u3002<\/p>\n<\/blockquote>\n
          \n
           3.\u534f\u53d8\u8fd4\u56de\u7c7b\u578b\uff1a\u4e00\u4e2a\u5b9e\u9645\u793a\u4f8b<\/strong> <\/h3>\n
          java \u5bf9\u534f\u53d8\u8fd4\u56de\u7c7b\u578b<\/strong>\u7684\u652f\u6301\u5141\u8bb8\u5b50\u7c7b\u8fd4\u56de\u6bd4\u8d85\u7c7b\u7684\u8fd4\u56de\u7c7b\u578b\u66f4\u5177\u4f53\u7684\u7c7b\u578b\u3002\u8fd9\u79cd\u65b9\u6cd5\u9075\u5faa solid \u539f\u5219\u4e2d\u7684\u91cc\u6c0f\u66ff\u6362\u539f\u7406<\/strong>\uff0c\u589e\u5f3a\u4e86\u4ee3\u7801\u7075\u6d3b\u6027\u3002<\/p>\n
          package oops.polymorphism;\n\n\/\/ Demonstrating covariant return type\npublic class CovariantReturnType extends MethodOverridingParent {\n\n    \/\/ Parent method's Return type is Number\n    \/\/ Since Integer is a subclass of Number, covariance is achieved\n    \/\/ Since Base class' method is public, subclass has to use public\n    @Override\n    public Integer getCount() {\n        return 40;\n    }\n\n    public static void main(String[] args) {\n        CovariantReturnType type = new CovariantReturnType();\n        System.out.println(type.getCount()); \/\/ Output: 40\n    }\n}\n<\/pre>\n
          \n
          \u8bf4\u660e<\/strong>\uff1a\u5728 covariantreturntype \u4e2d\uff0cgetcount() \u901a\u8fc7\u8fd4\u56de\u4e00\u4e2a integer\uff08number \u7684\u5b50\u7c7b\u578b\uff09\u6765\u8986\u76d6\u7236\u65b9\u6cd5\uff0c\u6f14\u793a\u4e86\u534f\u53d8\u8fd4\u56de\u7c7b\u578b<\/strong>\u3002\u8be5\u65b9\u6cd5\u4ecd\u7136\u662f\u516c\u5171\u7684\uff0c\u56e0\u4e3a java \u8981\u6c42\u91cd\u5199\u65b9\u6cd5\u7684\u8bbf\u95ee\u7ea7\u522b\u4e0d\u80fd\u964d\u4f4e\u3002<\/p>\n<\/blockquote>\n
          \n
           \u65b9\u6cd5\u91cd\u5199\u4e0e\u65b9\u6cd5\u91cd\u8f7d<\/strong> <\/h2>\n
            \n
          •  \u65b9\u6cd5\u91cd\u5199<\/strong>\u542f\u7528\u52a8\u6001\u591a\u6001\u6027\u5e76\u5728\u7ee7\u627f\u5c42\u6b21\u7ed3\u6784\u4e2d\u8fd0\u884c\u3002<\/li>\n
          •  \u65b9\u6cd5\u91cd\u8f7d<\/strong>\u662f\u901a\u8fc7\u5177\u6709\u4e0d\u540c\u7684\u53c2\u6570\u7c7b\u578b\u6216\u6570\u5b57\u5728\u540c\u4e00\u7c7b\u4e2d\u5b9e\u73b0\u9759\u6001\u591a\u6001\u6027\u7684\u4e00\u79cd\u5f62\u5f0f\u3002<\/li>\n<\/ul>\n
            \n
             \u4f55\u65f6\u4f7f\u7528\u65b9\u6cd5\u91cd\u5199<\/strong> <\/h2>\n
              \n
            1.  \u52a8\u6001\u65b9\u6cd5\u89e3\u6790<\/strong>\uff1a\u91cd\u5199\u65b9\u6cd5\u5728\u8fd0\u884c\u65f6\u6839\u636e\u5bf9\u8c61\u7c7b\u578b\u89e3\u6790\uff0c\u63d0\u4f9b\u66f4\u5927\u7684\u7075\u6d3b\u6027\u3002<\/li>\n
            2.  \u6269\u5c55\u884c\u4e3a<\/strong>\uff1a\u5b50\u7c7b\u53ef\u4ee5\u4fee\u6539\u6216\u6269\u5c55\u8d85\u7c7b\u65b9\u6cd5\u7684\u529f\u80fd\u3002<\/li>\n<\/ol>\n
              \n
               \u7ed3\u8bba<\/strong> <\/h2>\n
              \u901a\u8fc7\u7406\u89e3\u548c\u5e94\u7528\u65b9\u6cd5\u91cd\u5199\uff0c\u6211\u4eec\u53ef\u4ee5\u6784\u5efa\u66f4\u7075\u6d3b\u3001\u53ef\u91cd\u7528\u548c\u591a\u6001\u7684 java \u5e94\u7528\u7a0b\u5e8f\uff0c\u8fd9\u4e9b\u5e94\u7528\u7a0b\u5e8f\u9075\u5faa\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b<\/strong>\u539f\u5219\u3002<\/p>\n
              \n
               \u76f8\u5173\u5e16\u5b50 <\/h2>\n
                \n
              • \n
                java \u57fa\u7840\u77e5\u8bc6<\/p>\n<\/li>\n
              • \n
                \u6570\u7ec4\u9762\u8bd5\u8981\u70b9<\/p>\n<\/li>\n
              • \n
                java \u5185\u5b58\u57fa\u7840<\/p>\n<\/li>\n
              • \n
                java \u5173\u952e\u5b57\u8981\u70b9<\/p>\n<\/li>\n
              • \n
                \u96c6\u5408\u6846\u67b6\u8981\u70b9<\/p>\n<\/li>\n<\/ul>\n
                \u7f16\u7801\u5feb\u4e50\uff01<\/p>\n
                \u6587\u4e2d\u5173\u4e8e\u7684\u77e5\u8bc6\u4ecb\u7ecd\uff0c\u5e0c\u671b\u5bf9\u4f60\u7684\u5b66\u4e60\u6709\u6240\u5e2e\u52a9\uff01\u82e5\u662f\u53d7\u76ca\u532a\u6d45\uff0c\u90a3\u5c31\u52a8\u52a8\u9f20\u6807\u6536\u85cf\u8fd9\u7bc7\u300a\u591a\u6001\u6027\uff1aJava \u4e2d\u7684\u89e3\u7801\u65b9\u6cd5\u91cd\u5199\u300b\u6587\u7ae0\u5427\uff0c\u4e5f\u53ef\u5173\u6ce8\u516c\u4f17\u53f7\u4e86\u89e3\u76f8\u5173\u6280\u672f\u6587\u7ae0\u3002<\/p>\n
                      \u7248\u672c\u58f0\u660e \u672c\u6587\u8f6c\u8f7d\u4e8e\uff1adev.to \u5982\u6709\u4fb5\u72af\uff0c\u8bf7\u8054\u7cfb\u5220\u9664<\/p>\n","protected":false},"excerpt":{"rendered":"
                \u591a\u6001\u6027\uff1aJava \u4e2d\u7684\u89e3\u7801\u65b9\u6cd5\u91cd...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-203348","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/203348","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=203348"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/203348\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=203348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=203348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=203348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}