{"id":54396,"date":"2023-09-19T11:53:41","date_gmt":"2023-09-19T03:53:41","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=54396"},"modified":"2023-09-19T11:53:43","modified_gmt":"2023-09-19T03:53:43","slug":"java-%e4%b8%ad-newinstance-%e6%96%b9%e6%b3%95%e5%92%8c-new-%e7%9a%84%e5%8c%ba%e5%88%ab%e6%98%af%e4%bb%80%e4%b9%88","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/54396.html","title":{"rendered":"Java \u4e2d newInstance \u65b9\u6cd5\u548c new \u7684\u533a\u522b\u662f\u4ec0\u4e48"},"content":{"rendered":"\n
\n

\u5728Java\u4e2d\uff0c\u521b\u5efa\u5bf9\u8c61\u7684\u4e24\u79cd\u5e38\u89c1\u65b9\u5f0f\u662f\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\u548cClass<\/code>\u7c7b\u7684newInstance<\/code>\u65b9\u6cd5\u3002\u4e3b\u8981\u7684\u533a\u522b\u5305\u62ec\uff1a1\u3001\u521b\u5efa\u8fc7\u7a0b\uff1b2\u3001\u5f02\u5e38\u5904\u7406\uff1b3\u3001\u6027\u80fd\u5dee\u5f02\uff1b4\u3001\u4f7f\u7528\u8303\u56f4\uff1b5\u3001\u521d\u59cb\u5316\u5dee\u5f02\uff1b6\u3001\u53ef\u8bbf\u95ee\u6027\uff1b7\u3001Java\u7248\u672c\u548c\u66f4\u65b0\u3002\u4e86\u89e3\u8fd9\u4e9b\u533a\u522b\u5bf9\u4e8eJava\u5f00\u53d1\u8005\u5728\u7f16\u5199\u9ad8\u6548\u3001\u5b89\u5168\u548c\u53ef\u7ef4\u62a4\u7684\u4ee3\u7801\u65f6\u81f3\u5173\u91cd\u8981\u3002<\/p>\n<\/blockquote>\n\n\n

\n
\"\"<\/figure><\/div>\n\n\n

1\u3001\u521b\u5efa\u8fc7\u7a0b <\/h2>\n\n\n\n

\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\u76f4\u63a5\u521b\u5efa\u5bf9\u8c61\u65f6\uff0cJava\u5728\u7f16\u8bd1\u65f6\u5df2\u77e5\u8981\u521b\u5efa\u7684\u7c7b\u3002\u800c\u901a\u8fc7newInstance<\/code>\u65b9\u6cd5\uff0c\u5bf9\u8c61\u662f\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u521b\u5efa\u7684\uff0c\u4f9d\u8d56\u4e8e\u53cd\u5c04\u673a\u5236\u3002<\/p>\n\n\n\n

2\u3001\u5f02\u5e38\u5904\u7406 <\/h2>\n\n\n\n

newInstance<\/code>\u65b9\u6cd5\u53ef\u80fd\u4f1a\u629b\u51faInstantiationException<\/code>\u548cIllegalAccessException<\/code>\u4e24\u79cd\u5f02\u5e38\u3002\u8fd9\u8981\u6c42\u5f00\u53d1\u8005\u8fdb\u884c\u5f02\u5e38\u5904\u7406\u3002\u800cnew<\/code>\u5173\u952e\u5b57\u4e0d\u4f1a\u629b\u51fa\u8fd9\u4e9b\u5f02\u5e38\uff0c\u5b83\u53ef\u80fd\u4ea7\u751f\u7684\u5f02\u5e38\u7c7b\u578b\u4e0e\u6784\u9020\u51fd\u6570\u8c03\u7528\u76f8\u5173\u3002<\/p>\n\n\n\n

3\u3001\u6027\u80fd\u5dee\u5f02 <\/h2>\n\n\n\n

\u7531\u4e8enewInstance<\/code>\u65b9\u6cd5\u4f9d\u8d56\u4e8eJava\u7684\u53cd\u5c04\u673a\u5236\uff0c\u5176\u6027\u80fd\u7565\u4f4e\u4e8e\u76f4\u63a5\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\u3002\u4f46\u5728\u5927\u591a\u6570\u573a\u666f\u4e0b\uff0c\u8fd9\u79cd\u6027\u80fd\u5dee\u5f02\u662f\u53ef\u4ee5\u5ffd\u7565\u7684\u3002<\/p>\n\n\n\n

4\u3001\u4f7f\u7528\u8303\u56f4 <\/h2>\n\n\n\n

\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\u9700\u8981\u5728\u7f16\u5199\u4ee3\u7801\u65f6\u660e\u786e\u77e5\u9053\u8981\u5b9e\u4f8b\u5316\u7684\u7c7b\u3002\u800cnewInstance<\/code>\u53ef\u4ee5\u52a8\u6001\u5730\u521b\u5efa\u4efb\u610f\u4e00\u4e2a\u5df2\u77e5\u5168\u7c7b\u540d\u7684\u7c7b\u7684\u5bf9\u8c61\uff0c\u8fd9\u5728\u67d0\u4e9b\u52a8\u6001\u52a0\u8f7d\u6216\u63d2\u4ef6\u7cfb\u7edf\u4e2d\u662f\u5f88\u6709\u7528\u7684\u3002<\/p>\n\n\n\n

5\u3001\u521d\u59cb\u5316\u5dee\u5f02 <\/h2>\n\n\n\n

\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\u4f1a\u89e6\u53d1\u9759\u6001\u4ee3\u7801\u5757\u548c\u5b9e\u4f8b\u521d\u59cb\u5316\u5757\u3002\u800cnewInstance<\/code>\u9664\u4e86\u89e6\u53d1\u5b9e\u4f8b\u521d\u59cb\u5316\u5757\u5916\uff0c\u8fd8\u4f1a\u89e6\u53d1\u7c7b\u7684\u9759\u6001\u4ee3\u7801\u5757\uff08\u5982\u679c\u6b64\u7c7b\u8fd8\u672a\u88ab\u52a0\u8f7d\uff09\u3002<\/p>\n\n\n\n

6\u3001\u53ef\u8bbf\u95ee\u6027 <\/h2>\n\n\n\n

newInstance<\/code>\u65b9\u6cd5\u53ea\u80fd\u8c03\u7528\u516c\u5171\u7684\u65e0\u53c2\u6784\u9020\u51fd\u6570\u3002\u5982\u679c\u7c7b\u6ca1\u6709\u516c\u5171\u7684\u65e0\u53c2\u6784\u9020\u51fd\u6570\uff0cnewInstance<\/code>\u4f1a\u629b\u51faInstantiationException<\/code>\u3002\u800cnew<\/code>\u5173\u952e\u5b57\u53ef\u4ee5\u8c03\u7528\u4efb\u4f55\u53ef\u89c1\u7684\u6784\u9020\u51fd\u6570\u3002<\/p>\n\n\n\n

7\u3001Java\u7248\u672c\u548c\u66f4\u65b0 <\/h2>\n\n\n\n

\u5728Java 9\u53ca\u540e\u7eed\u7248\u672c\u4e2d\uff0cnewInstance<\/code>\u65b9\u6cd5\u5df2\u88ab\u6807\u8bb0\u4e3a\u8fc7\u65f6\uff0c\u5e76\u5efa\u8bae\u4f7f\u7528Constructor.newInstance<\/code>\u6765\u66ff\u4ee3\uff0c\u56e0\u4e3a\u5b83\u63d0\u4f9b\u4e86\u66f4\u597d\u7684\u5f02\u5e38\u5904\u7406\u548c\u66f4\u5927\u7684\u7075\u6d3b\u6027\u3002<\/p>\n\n\n\n

\u603b\u7ed3\uff1a\u867d\u7136new<\/code>\u5173\u952e\u5b57\u548cnewInstance<\/code>\u65b9\u6cd5\u90fd\u7528\u4e8eJava\u5bf9\u8c61\u7684\u521b\u5efa\uff0c\u4f46\u5b83\u4eec\u5728\u4f7f\u7528\u65b9\u5f0f\u548c\u5e94\u7528\u573a\u666f\u4e0a\u6709\u6240\u4e0d\u540c\u3002\u9009\u62e9\u4f7f\u7528\u54ea\u79cd\u65b9\u6cd5\u53d6\u51b3\u4e8e\u5177\u4f53\u7684\u9700\u6c42\u548c\u573a\u666f\u3002\u5bf9\u4e8e\u5e38\u89c4\u7684\u5bf9\u8c61\u521b\u5efa\uff0c\u901a\u5e38\u63a8\u8350\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\uff0c\u56e0\u4e3a\u5b83\u66f4\u76f4\u89c2\u3001\u6548\u7387\u66f4\u9ad8\u3002\u4f46\u5728\u9700\u8981\u52a8\u6001\u521b\u5efa\u5bf9\u8c61\u7684\u573a\u5408\uff0c\u4f8b\u5982\u6846\u67b6\u5f00\u53d1\u6216\u63d2\u4ef6\u7cfb\u7edf\uff0cnewInstance<\/code>\u53ca\u5176\u76f8\u5173\u7684\u53cd\u5c04\u65b9\u6cd5\u662f\u4e00\u4e2a\u5f88\u597d\u7684\u9009\u62e9\u3002<\/p>\n\n\n\n

\n\n\n\n

\u5e38\u89c1\u95ee\u7b54<\/strong><\/h2>\n\n\n\n
\n

Q1: \u4e3a\u4ec0\u4e48\u8bf4newInstance<\/code>\u7684\u6027\u80fd\u76f8\u5bf9\u8f83\u4f4e\uff1f<\/strong><\/p>\n\n\n\n

\u7b54\uff1a<\/strong> newInstance<\/code>\u65b9\u6cd5\u57fa\u4e8eJava\u7684\u53cd\u5c04\u673a\u5236\u521b\u5efa\u5bf9\u8c61\u3002\u53cd\u5c04\u6d89\u53ca\u5230\u4e00\u7cfb\u5217\u7684\u5185\u90e8\u68c0\u67e5\u548c\u5bf9\u8c61\u7684\u52a8\u6001\u751f\u6210\uff0c\u8fd9\u4f1a\u5bfc\u81f4\u5b83\u6bd4\u76f4\u63a5\u4f7f\u7528new<\/code>\u5173\u952e\u5b57\u5b9e\u4f8b\u5316\u5bf9\u8c61\u7684\u6027\u80fd\u7a0d\u4f4e\u3002\u4f46\u5728\u5b9e\u9645\u7684\u5e94\u7528\u4e2d\uff0c\u9664\u975e\u662f\u9ad8\u9891\u7e41\u7684\u5bf9\u8c61\u521b\u5efa\uff0c\u8fd9\u79cd\u6027\u80fd\u5dee\u5f02\u901a\u5e38\u662f\u53ef\u4ee5\u63a5\u53d7\u7684\u3002<\/p>\n<\/div>\n\n\n\n

\n

Q2: \u662f\u5426\u53ef\u4ee5\u4f7f\u7528newInstance<\/code>\u65b9\u6cd5\u521b\u5efa\u6570\u7ec4\u6216\u57fa\u672c\u6570\u636e\u7c7b\u578b\u7684\u5b9e\u4f8b\uff1f<\/strong><\/p>\n\n\n\n

\u7b54\uff1a<\/strong> \u4e0d\u53ef\u4ee5\u3002newInstance<\/code>\u65b9\u6cd5\u53ea\u80fd\u7528\u4e8e\u521b\u5efa\u7c7b\u5b9e\u4f8b\uff0c\u5e76\u4e14\u8be5\u7c7b\u5fc5\u987b\u6709\u4e00\u4e2a\u516c\u5f00\u7684\u65e0\u53c2\u6570\u6784\u9020\u51fd\u6570\u3002\u5bf9\u4e8e\u6570\u7ec4\u6216\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff0c\u6211\u4eec\u9700\u8981\u4f7f\u7528\u5176\u4ed6\u65b9\u6cd5\u548c\u6280\u672f\u3002<\/p>\n<\/div>\n\n\n\n

\n

Q3: \u5728Java\u7684\u65b0\u7248\u672c\u4e2d\uff0c\u4e3a\u4ec0\u4e48\u63a8\u8350\u4f7f\u7528Constructor.newInstance<\/code>\u800c\u4e0d\u662fClass.newInstance<\/code>\uff1f<\/strong><\/p>\n\n\n\n

\u7b54\uff1a<\/strong> Class.newInstance<\/code>\u5728\u5904\u7406\u6784\u9020\u51fd\u6570\u629b\u51fa\u7684\u5f02\u5e38\u65f6\u6709\u4e00\u4e9b\u4e0d\u8db3\u4e4b\u5904\uff0c\u5b83\u4f1a\u5c06\u4efb\u4f55\u7531\u6784\u9020\u51fd\u6570\u629b\u51fa\u7684\u68c0\u67e5\u578b\u5f02\u5e38\u8f6c\u5316\u4e3a\u672a\u68c0\u67e5\u7684InvocationTargetException<\/code>\u3002\u800cConstructor.newInstance<\/code>\u65b9\u6cd5\u63d0\u4f9b\u4e86\u66f4\u660e\u786e\u7684\u5f02\u5e38\u5904\u7406\uff0c\u5141\u8bb8\u8c03\u7528\u8005\u5904\u7406\u539f\u59cb\u5f02\u5e38\u3002\u56e0\u6b64\uff0c\u4e3a\u4e86\u66f4\u597d\u7684\u5f02\u5e38\u5904\u7406\u548c\u589e\u52a0\u7684\u7075\u6d3b\u6027\uff0c\u63a8\u8350\u4f7f\u7528Constructor.newInstance<\/code>\u3002<\/p>\n<\/div>\n\n\n\n

\n

Q4: \u5982\u679c\u7c7b\u6ca1\u6709\u9ed8\u8ba4\u7684\u65e0\u53c2\u6784\u9020\u51fd\u6570\uff0c\u5982\u4f55\u901a\u8fc7\u53cd\u5c04\u521b\u5efa\u5b9e\u4f8b\uff1f<\/strong><\/p>\n\n\n\n

\u7b54\uff1a<\/strong> \u5982\u679c\u7c7b\u6ca1\u6709\u9ed8\u8ba4\u7684\u65e0\u53c2\u6784\u9020\u51fd\u6570\uff0c\u6211\u4eec\u53ef\u4ee5\u9996\u5148\u4f7f\u7528Class<\/code>\u5bf9\u8c61\u83b7\u53d6\u6240\u9700\u7684Constructor<\/code>\u5bf9\u8c61\uff0c\u7136\u540e\u4f7f\u7528Constructor<\/code>\u5bf9\u8c61\u7684newInstance<\/code>\u65b9\u6cd5\u5e76\u4f20\u9012\u5fc5\u8981\u7684\u53c2\u6570\u6765\u521b\u5efa\u5b9e\u4f8b\u3002\u8fd9\u6837\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u53cd\u5c04\u521b\u5efa\u5177\u6709\u7279\u5b9a\u6784\u9020\u51fd\u6570\u7684\u7c7b\u7684\u5b9e\u4f8b\u3002<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"\u5728Java\u4e2d\uff0c\u521b\u5efa\u5bf9\u8c61\u7684\u4e24\u79cd\u5e38\u89c1\u65b9\u5f0f\u662f\u4f7f\u7528new\u5173\u952e\u5b57\u548cClass\u7c7b\u7684newInstance\u65b9\u6cd5\u3002\u4e3b\u8981\u7684\u533a\u522b\u5305 […]","protected":false},"author":7,"featured_media":54398,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/54396"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=54396"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/54396\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/54398"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=54396"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=54396"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=54396"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}