{"id":9963,"date":"2023-11-28T21:22:16","date_gmt":"2023-11-28T13:22:16","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=9963"},"modified":"2023-12-07T10:34:21","modified_gmt":"2023-12-07T02:34:21","slug":"jvm-zhong-de-da-po-shuang-qin-wei-pai-ji-zhi-de-li","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/11\/28\/jvm-zhong-de-da-po-shuang-qin-wei-pai-ji-zhi-de-li\/","title":{"rendered":"JVM\u4e2d\u7684\u6253\u7834\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u7684\u4f8b\u5b50\uff0c\u4e3a\u4ec0\u4e48\u8981\u6253\u7834?"},"content":{"rendered":"<p>\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u662fJava\u7c7b\u52a0\u8f7d\u5668\uff08ClassLoader\uff09\u7684\u4e00\u79cd\u8bbe\u8ba1\u6a21\u5f0f\uff0c\u5b83\u5b9a\u4e49\u4e86\u7c7b\u52a0\u8f7d\u5668\u4e4b\u95f4\u7684\u5c42\u6b21\u5173\u7cfb\u3002\u6839\u636e\u8fd9\u4e2a\u673a\u5236\uff0c\u5f53\u4e00\u4e2a\u7c7b\u52a0\u8f7d\u5668\u6536\u5230\u7c7b\u52a0\u8f7d\u8bf7\u6c42\u65f6\uff0c\u5b83\u9996\u5148\u4f1a\u5c1d\u8bd5\u5c06\u52a0\u8f7d\u4efb\u52a1\u59d4\u6d3e\u7ed9\u5176\u7236\u7c7b\u52a0\u8f7d\u5668\uff0c\u53ea\u6709\u5f53\u7236\u7c7b\u52a0\u8f7d\u5668\u65e0\u6cd5\u5b8c\u6210\u52a0\u8f7d\u4efb\u52a1\u65f6\uff0c\u624d\u7531\u5f53\u524d\u7c7b\u52a0\u8f7d\u5668\u81ea\u5df1\u5b8c\u6210\u52a0\u8f7d\u3002\u8fd9\u4e2a\u673a\u5236\u6709\u52a9\u4e8e\u4fdd\u6301\u7c7b\u52a0\u8f7d\u7684\u4e00\u81f4\u6027\u548c\u9694\u79bb\u6027\u3002<\/p>\n<p>\u6253\u7834\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u7684\u4e3b\u8981\u539f\u56e0\u4e4b\u4e00\u662f\u4e3a\u4e86\u5b9e\u73b0\u7c7b\u52a0\u8f7d\u7684\u5b9a\u5236\u548c\u7075\u6d3b\u6027\u3002\u5728\u67d0\u4e9b\u7279\u5b9a\u573a\u666f\u4e0b\uff0c\u4f8b\u5982\u5728\u5e94\u7528\u670d\u52a1\u5668\u6216\u6846\u67b6\u4e2d\uff0c\u53ef\u80fd\u9700\u8981\u52a0\u8f7d\u4e00\u4e9b\u5b9a\u5236\u7684\u7c7b\uff0c\u800c\u8fd9\u4e9b\u7c7b\u53ef\u80fd\u4e0e\u7cfb\u7edf\u7c7b\u5e93\u5b58\u5728\u51b2\u7a81\u3002\u4e3a\u4e86\u89e3\u51b3\u8fd9\u79cd\u95ee\u9898\uff0c\u53ef\u4ee5\u6253\u7834\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\uff0c\u81ea\u5b9a\u4e49\u7c7b\u52a0\u8f7d\u5668\u6765\u52a0\u8f7d\u7279\u5b9a\u7684\u7c7b\u3002<\/p>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u793a\u4f8b\uff0c\u6f14\u793a\u5982\u4f55\u901a\u8fc7\u6253\u7834\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u52a0\u8f7d\u7c7b\uff1a<\/p>\n<pre><code class=\"language-java\">public class CustomClassLoader extends ClassLoader {\n    @Override\n    protected Class&lt;?&gt; findClass(String name) throws ClassNotFoundException {\n        \/\/ \u81ea\u5b9a\u4e49\u52a0\u8f7d\u903b\u8f91\uff0c\u4f8b\u5982\u4ece\u7279\u5b9a\u4f4d\u7f6e\u52a0\u8f7d\u7c7b\u7684\u5b57\u8282\u7801\n        byte[] classData = loadClassData(name);\n        if (classData == null) {\n            throw new ClassNotFoundException();\n        } else {\n            \/\/ \u4f7f\u7528defineClass\u65b9\u6cd5\u5b9a\u4e49\u7c7b\n            return defineClass(name, classData, 0, classData.length);\n        }\n    }\n\n    private byte[] loadClassData(String className) {\n        \/\/ \u4ece\u7279\u5b9a\u4f4d\u7f6e\u52a0\u8f7d\u7c7b\u7684\u5b57\u8282\u7801\uff0c\u8fd9\u91cc\u7684\u5b9e\u73b0\u9700\u8981\u6839\u636e\u5177\u4f53\u9700\u6c42\u7f16\u5199\n        \/\/ \u8fd4\u56de\u7c7b\u7684\u5b57\u8282\u6570\u7ec4\n        \/\/ ...\n    }\n\n    public static void main(String[] args) {\n        \/\/ \u4f7f\u7528\u81ea\u5b9a\u4e49\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u7c7b\n        CustomClassLoader customClassLoader = new CustomClassLoader();\n        try {\n            Class&lt;?&gt; customClass = customClassLoader.loadClass(&quot;com.example.CustomClass&quot;);\n            \/\/ \u4f7f\u7528\u52a0\u8f7d\u7684\u7c7b\u8fdb\u884c\u64cd\u4f5c\n            \/\/ ...\n        } catch (ClassNotFoundException e) {\n            e.printStackTrace();\n        }\n    }\n}\n<\/code><\/pre>\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c<code>CustomClassLoader<\/code> \u7ee7\u627f\u4e86 <code>ClassLoader<\/code> \u5e76\u8986\u5199\u4e86 <code>findClass<\/code> \u65b9\u6cd5\uff0c\u901a\u8fc7\u81ea\u5b9a\u4e49\u7684\u52a0\u8f7d\u903b\u8f91\u52a0\u8f7d\u7c7b\u7684\u5b57\u8282\u7801\u3002\u5728 <code>main<\/code> \u65b9\u6cd5\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528 <code>CustomClassLoader<\/code> \u52a0\u8f7d\u4e86\u4e00\u4e2a\u81ea\u5b9a\u4e49\u7684\u7c7b <code>com.example.CustomClass<\/code>\u3002<\/p>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u6253\u7834\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u5e76\u4e0d\u662f\u4e00\u4e2a\u63a8\u8350\u7684\u505a\u6cd5\uff0c\u56e0\u4e3a\u5b83\u53ef\u80fd\u5bfc\u81f4\u7c7b\u52a0\u8f7d\u7684\u4e0d\u4e00\u81f4\u6027\u548c\u9694\u79bb\u6027\u964d\u4f4e\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u53ea\u6709\u5728\u786e\u5207\u4e86\u89e3\u98ce\u9669\u548c\u5fc5\u987b\u8981\u5b9e\u73b0\u5b9a\u5236\u7c7b\u52a0\u8f7d\u903b\u8f91\u7684\u60c5\u51b5\u4e0b\uff0c\u624d\u5e94\u8be5\u6253\u7834\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u53cc\u4eb2\u59d4\u6d3e\u673a\u5236\u662fJava\u7c7b\u52a0\u8f7d\u5668\uff08ClassLoader\uff09\u7684\u4e00\u79cd\u8bbe\u8ba1\u6a21\u5f0f\uff0c\u5b83\u5b9a\u4e49\u4e86\u7c7b\u52a0\u8f7d\u5668\u4e4b\u95f4\u7684\u5c42\u6b21\u5173\u7cfb\u3002\u6839\u636e\u8fd9 [&hellip;]<\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[119],"tags":[],"class_list":["post-9963","post","type-post","status-publish","format-standard","hentry","category-jvm"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/9963","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=9963"}],"version-history":[{"count":2,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/9963\/revisions"}],"predecessor-version":[{"id":16776,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/9963\/revisions\/16776"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=9963"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=9963"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=9963"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}