{"id":202739,"date":"2025-05-22T10:40:07","date_gmt":"2025-05-22T02:40:07","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202739\/"},"modified":"2025-05-22T10:40:07","modified_gmt":"2025-05-22T02:40:07","slug":"%e5%a6%82%e4%bd%95%e5%88%a9%e7%94%a8%e5%ad%97%e8%8a%82%e7%a0%81%e5%a2%9e%e5%bc%ba%e6%8f%90%e5%8d%87-java-%e5%87%bd%e6%95%b0%e6%80%a7%e8%83%bd%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202739\/","title":{"rendered":"\u5982\u4f55\u5229\u7528\u5b57\u8282\u7801\u589e\u5f3a\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd\uff1f"},"content":{"rendered":"

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

\u5982\u4f55\u5229\u7528\u5b57\u8282\u7801\u589e\u5f3a\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd\uff1f<\/h1>\n

\u4f60\u5728\u5b66\u4e60\u6587\u7ae0<\/span>\u76f8\u5173\u7684\u77e5\u8bc6\u5417\uff1f\u672c\u6587\u300a\u5982\u4f55\u5229\u7528\u5b57\u8282\u7801\u589e\u5f3a\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd\uff1f\u300b<\/span>\uff0c\u4e3b\u8981\u4ecb\u7ecd\u7684\u5185\u5bb9\u5c31\u6d89\u53ca\u5230<\/span>\uff0c\u5982\u679c\u4f60\u60f3\u63d0\u5347\u81ea\u5df1\u7684\u5f00\u53d1\u80fd\u529b\uff0c\u5c31\u4e0d\u8981\u9519\u8fc7\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5927\u5bb6\u8981\u77e5\u9053\u7f16\u7a0b\u7406\u8bba\u57fa\u7840\u548c\u5b9e\u6218\u64cd\u4f5c\u90fd\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u54e6\uff01<\/p>\n

\u5b57\u8282\u7801\u589e\u5f3a\u53ef\u901a\u8fc7\u4fee\u6539\u7c7b\u5b57\u8282\u7801\u6765\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd\u3002\u4f7f\u7528 ASM \u7b49\u5de5\u5177\u5b9e\u73b0\u5b57\u8282\u7801\u589e\u5f3a\uff0c\u5177\u4f53\u64cd\u4f5c\u5305\u62ec\uff1a\u8df3\u8fc7 Strings \u4e0a\u7684\u65b9\u6cd5\u8c03\u7528\uff0c\u76f4\u63a5\u6267\u884c\u64cd\u4f5c\u4ee5\u51cf\u5c11\u8c03\u7528\u5f00\u9500\u3002\u81ea\u5b9a\u4e49 ClassFileTransformer \u6765\u8f6c\u6362\u7279\u5b9a\u7c7b\u7684\u65b9\u6cd5\uff0c\u5e94\u7528\u4f18\u5316\u3002\u6ce8\u518c ClassFileTransformer \u4e3a Java \u4ee3\u7406\uff0c\u4ee5\u5728\u7c7b\u52a0\u8f7d\u65f6\u5e94\u7528\u4f18\u5316\u3002\u6ce8\u610f\uff1a\u5b57\u8282\u7801\u589e\u5f3a\u53ef\u80fd\u5f71\u54cd\u5e94\u7528\u7a0b\u5e8f\u7a33\u5b9a\u6027\uff0c\u4f7f\u7528\u524d\u5e94\u5145\u5206\u6d4b\u8bd5\u3002<\/p>\n

<\/p>\n

\u5982\u4f55\u5229\u7528\u5b57\u8282\u7801\u589e\u5f3a\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd<\/strong><\/p>\n

\u5b57\u8282\u7801\u589e\u5f3a\u662f\u4e00\u79cd\u901a\u8fc7\u4fee\u6539\u7c7b\u5b57\u8282\u7801\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd\u7684\u6280\u672f\u3002\u8981\u5b9e\u73b0\u5b57\u8282\u7801\u589e\u5f3a\uff0c\u53ef\u4ee5\u4f7f\u7528\u8bf8\u5982 ASM\u3001Javassist \u6216 Byte Buddy \u7b49\u5de5\u5177\u3002<\/p>\n

\u5b9e\u6218\u6848\u4f8b<\/strong><\/p>\n

\u8003\u8651\u4ee5\u4e0b Java \u51fd\u6570\uff0c\u5b83\u5c06\u4e00\u4e2a\u5b57\u7b26\u4e32\u5217\u8868\u8f6c\u6362\u4e3a\u53e6\u4e00\u4e2a\u5b57\u7b26\u4e32\u5217\u8868\uff0c\u5e76\u5c06\u6bcf\u4e2a\u5143\u7d20\u5927\u5199\uff1a<\/p>\n

List<String> convertToUppercase(List<String> input) {\n  List<String> output = new ArrayList<>();\n  for (String str : input) {\n    output.add(str.toUpperCase());\n  }\n  return output;\n}<\/pre>\n
\u4f7f\u7528\u5b57\u8282\u7801\u589e\u5f3a\uff0c\u6211\u4eec\u53ef\u4ee5\u4f18\u5316\u6b64\u51fd\u6570\uff0c\u4f7f\u5176\u8df3\u8fc7 Strings \u4e0a\u7684\u8c03\u7528\uff0c\u76f4\u63a5\u6267\u884c toUpperCase()<\/code> \u64cd\u4f5c\uff0c\u4ece\u800c\u51cf\u5c11\u65b9\u6cd5\u8c03\u7528\u5f00\u9500\uff1a<\/p>\n
import org.objectweb.asm.ClassReader;\nimport org.objectweb.asm.ClassWriter;\nimport org.objectweb.asm.MethodVisitor;\nimport org.objectweb.asm.Opcodes;\nimport java.lang.instrument.ClassFileTransformer;\nimport java.lang.instrument.Instrumentation;\nimport java.security.ProtectionDomain;\n\npublic class FunctionTransformer implements ClassFileTransformer {\n\n  @Override\n  public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) {\n    if (!className.equals(\"com\/example\/Converter\")) {\n      return classfileBuffer;\n    }\n\n    ClassReader cr = new ClassReader(classfileBuffer);\n    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);\n    cr.accept(new FunctionVisitor(cw), 0);\n    return cw.toByteArray();\n  }\n\n  static class FunctionVisitor extends MethodVisitor { \/\/ \u8df3\u8fc7 `toUpperCase` \u8c03\u7528\n\n    public FunctionVisitor(ClassVisitor cv) {\n      super(Opcodes.ASM5, cv);\n    }\n\n    @Override\n    public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf) {\n      if (opcode == Opcodes.INVOKEVIRTUAL && owner.equals(\"java\/lang\/String\") && name.equals(\"toUpperCase\") && desc.equals(\"()Ljava\/lang\/String;\")) {\n        super.visitInsn(Opcodes.SWAP);\n        super.visitMethodInsn(Opcodes.INVOKEVIRTUAL, \"java\/lang\/StringBuffer\", \"append\", \"(Ljava\/lang\/String;)Ljava\/lang\/StringBuffer;\", false);\n        super.visitInsn(Opcodes.SWAP);\n      } else {\n        super.visitMethodInsn(opcode, owner, name, desc, itf);\n      }\n    }\n  }\n\n  public static void premain(String agentArgs, Instrumentation inst) {\n    inst.addTransformer(new FunctionTransformer());\n  }\n}<\/pre>\n
\u5c06 FunctionTransformer<\/code> \u6ce8\u518c\u4e3a Java \u4ee3\u7406\u540e\uff0c\u5b83\u5c06\u5728\u5e94\u7528\u7a0b\u5e8f\u7c7b\u52a0\u8f7d\u65f6\u5e94\u7528\u4e0a\u8ff0\u4f18\u5316\uff0c\u63d0\u5347 convertToUppercase<\/code> \u51fd\u6570\u7684\u6027\u80fd\u3002<\/p>\n
\u6ce8\u610f\uff1a<\/strong>\u5b57\u8282\u7801\u589e\u5f3a\u53ef\u80fd\u5f71\u54cd\u5e94\u7528\u7a0b\u5e8f\u7684\u7a33\u5b9a\u6027\u3002\u56e0\u6b64\uff0c\u5728\u751f\u4ea7\u73af\u5883\u4e2d\u4f7f\u7528\u4e4b\u524d\uff0c\u5bf9\u5176\u8fdb\u884c\u5145\u5206\u6d4b\u8bd5\u975e\u5e38\u91cd\u8981\u3002<\/p>\n
\u597d\u4e86\uff0c\u672c\u6587\u5230\u6b64\u7ed3\u675f\uff0c\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u300a\u5982\u4f55\u5229\u7528\u5b57\u8282\u7801\u589e\u5f3a\u63d0\u5347 Java \u51fd\u6570\u6027\u80fd\uff1f\u300b\uff0c\u5e0c\u671b\u672c\u6587\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff01\u5173\u6ce8\u516c\u4f17\u53f7\uff0c\u7ed9\u5927\u5bb6\u5206\u4eab\u66f4\u591a\u6587\u7ae0\u77e5\u8bc6\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5982\u4f55\u5229\u7528\u5b57\u8282\u7801\u589e\u5f3a\u63d0\u5347 Java...<\/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-202739","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202739","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=202739"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202739\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202739"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202739"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202739"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}