Java Agent实现系统数据采集

package command; import enhancer.AsmEnhancer; import enhancer.MyAdvice; import net.bytebuddy.agent.builder.AgentBuilder; import net.bytebuddy.asm.Advice; import net.bytebuddy.matcher.ElementMatchers; import org.jd.core.v1.ClassFileToJavaSourceDecompiler; import org.jd.core.v1.api.loader.Loader; import org.jd.core.v1.api.loader.LoaderException; import org.jd.core.v1.api.printer.Printer; import java.lang.instrument.ClassFileTransformer; import java.lang.instrument.IllegalClassFormatException; import java.lang.instrument.Instrumentation; import java.lang.instrument.UnmodifiableClassException; import java.security.ProtectionDomain; import java.util.HashSet; import java.util.Scanner; import java.util.Set; import java.util.stream.Collectors; public class ClassCommand { /** * 打印所有的类加载器 * 形参直接用Instrumentation对象，在premain或者agentmain方法中，JDK会自己注入 */ public static void printAllClassLoader(Instrumentation inst) { //获取所有已加载的类 Class[] allLoadedClasses = inst.getAllLoadedClasses(); //用于去重，因为类加载器就那几种 Set<ClassLoader> classLoaderSet = new HashSet<>(); for (Class loadedClass : allLoadedClasses) { ClassLoader classLoader = loadedClass.getClassLoader(); classLoaderSet.add(classLoader); } //打印类加载器 String classLoaderInfo = classLoaderSet.stream() .map(x -> { //获取启动类加载器的结果为null，这里我直接给个固定的名字 if (x == null) { return "BootStrapClassLoader"; } //其他的类加载器就正常输出 return x.getName(); }) //类加载器名字为空的不要 .filter(x -> x != null) .distinct() .sorted(String::compareTo) .collect(Collectors.joining(",")); System.out.println(classLoaderInfo); } /** * 打印类的源代码 */ public static void printClassSourceCode(Instrumentation inst) { //输入全类名 System.out.println("请输入全类名："); Scanner scanner = new Scanner(System.in); String className = scanner.next(); //获取所有已加载的类，从中找到用户要的类的class对象 Class[] allLoadedClasses = inst.getAllLoadedClasses(); for (Class loadedClass : allLoadedClasses) { //找到了 if (className.equals(loadedClass.getName())) { //转换器 ClassFileTransformer transformer = new ClassFileTransformer() { @Override //transform方法传入一个字节码信息，返回一个增强后的字节码信息，以下代码的写法，返回null即不增强，这里只要原来的字节码 public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { //通过jd-code反编译，打印出源码 printJdCoreSourceCode(classfileBuffer, className); return ClassFileTransformer.super.transform(loader, className, classBeingRedefined, protectionDomain, classfileBuffer); //直接调用以有的父类，返回null，即不改，因为这里只要获取最初的字节码 } }; //添加转换器，让转换器生效，参数二为true即可手动触发 inst.addTransformer(transformer, true); //触发转换器 try { inst.retransformClasses(loadedClass); } catch (UnmodifiableClassException e) { e.printStackTrace(); } finally { //使用完之后删除转换器 inst.removeTransformer(transformer); } } } } /** * jd-code打印源码 * bytes 字节码信息 */ private static void printJdCoreSourceCode(byte[] bytes, String className) { //loader对象 Loader loader = new Loader() { @Override public byte[] load(String internalName) throws LoaderException { return bytes; } @Override public boolean canLoad(String internalName) { return true; //类可加载 } }; //Printer对象，注意重写end方法，打印源代码 Printer printer = new Printer() { protected static final String TAB = " "; protected static final String NEWLINE = "\n"; protected int indentationCount = 0; protected StringBuilder sb = new StringBuilder(); @Override public String toString() { return sb.toString(); } @Override public void start(int maxLineNumber, int majorVersion, int minorVersion) { } @Override public void end() { //打印源代码 System.out.println(sb); } @Override public void printText(String text) { sb.append(text); } @Override public void printNumericConstant(String constant) { sb.append(constant); } @Override public void printStringConstant(String constant, String ownerInternalName) { sb.append(constant); } @Override public void printKeyword(String keyword) { sb.append(keyword); } @Override public void printDeclaration(int type, String internalTypeName, String name, String descriptor) { sb.append(name); } @Override public void printReference(int type, String internalTypeName, String name, String descriptor, String ownerInternalName) { sb.append(name); } @Override public void indent() { this.indentationCount++; } @Override public void unindent() { this.indentationCount--; } @Override public void startLine(int lineNumber) { for (int i = 0; i < indentationCount; i++) sb.append(TAB); } @Override public void endLine() { sb.append(NEWLINE); } @Override public void extraLine(int count) { while (count-- > 0) sb.append(NEWLINE); } @Override public void startMarker(int type) { } @Override public void endMarker(int type) { } }; //通过jd-code打印 ClassFileToJavaSourceDecompiler decompiler = new ClassFileToJavaSourceDecompiler(); try { decompiler.decompile(loader, printer, className); } catch (Exception e) { e.printStackTrace(); } } //对类进行增强 public static void enhanceClass(Instrumentation inst) { System.out.println("请输入类名:"); //让用户输入类名 Scanner scanner = new Scanner(System.in); String className = scanner.next(); //根据类名找到class对象 Class[] allLoadedClasses = inst.getAll