Java CodeAttribute类代码示例

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * 获取方法的参数名
 * @param clazz  类
 * @param method 方法
 * @return 方法名称数组
 * @throws NotFoundException .{@link NotFoundException}
 */
public static String[] getParamNames(Class clazz, String method) throws NotFoundException {
    ClassPool pool = ClassPool.getDefault();
    CtClass cc = pool.get(clazz.getName());
    CtMethod cm = cc.getDeclaredMethod(method);
    // 使用javaassist的反射方法获取方法的参数名
    MethodInfo methodInfo = cm.getMethodInfo();
    CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
    LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
    if (attr == null) {
        throw new NotFoundException("cannot get LocalVariableAttribute");
    }
    String[] paramNames = new String[cm.getParameterTypes().length];
    int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
    for (int i = 0; i < paramNames.length; i++) {
        paramNames[i] = attr.variableName(i + pos);
    }
    return paramNames;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * get method parameter names
 * @param cls
 * @param method
 * @return
 * @throws Exception
 */
public static String[] getParamNames(Class<?> cls, Method method) throws Exception {
    ClassPool pool = ClassPool.getDefault();
    CtClass cc = pool.get(cls.getName());

    Class<?>[] paramAry = method.getParameterTypes();
    String[] paramTypeNames = new String[paramAry.length];
    for (int i = 0; i < paramAry.length; i++) {
        paramTypeNames[i] = paramAry[i].getName();
    }

    CtMethod cm = cc.getDeclaredMethod(method.getName(), pool.get(paramTypeNames));

    MethodInfo methodInfo = cm.getMethodInfo();
    CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
    LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
    if (attr == null) {
        throw new Exception("class:" + cls.getName() + ", have no LocalVariableTable, please use javac -g:{vars} to compile the source file");
    }
    String[] paramNames = new String[cm.getParameterTypes().length];
    int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
    for (int i = 0; i < paramNames.length; i++) {
        paramNames[i] = attr.variableName(i + pos);
    }
    return paramNames;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
private void transformInvokevirtualsIntoPutAndGetfields(ClassFile classfile) throws CannotCompileException, BadBytecode {
	for ( Object o : classfile.getMethods() ) {
		final MethodInfo methodInfo = (MethodInfo) o;
		final String methodName = methodInfo.getName();
		if ( methodName.startsWith( EACH_READ_METHOD_PREFIX )
				|| methodName.startsWith( EACH_WRITE_METHOD_PREFIX )
				|| methodName.equals( GETFIELDHANDLER_METHOD_NAME )
				|| methodName.equals( SETFIELDHANDLER_METHOD_NAME ) ) {
			continue;
		}

		final CodeAttribute codeAttr = methodInfo.getCodeAttribute();
		if ( codeAttr == null ) {
			continue;
		}

		final CodeIterator iter = codeAttr.iterator();
		while ( iter.hasNext() ) {
			int pos = iter.next();
			pos = transformInvokevirtualsIntoGetfields( classfile, iter, pos );
			transformInvokevirtualsIntoPutfields( classfile, iter, pos );
		}
		final StackMapTable smt = MapMaker.make( classPool, methodInfo );
		codeAttr.setAttribute( smt );
	}
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * 获取方法参数名
 * @param method
 * @return 
 */
public static String[] getParamName(Method method) throws Exception {
	ClassPool pool = ClassPool.getDefault();
	CtClass ctClass = pool.get(method.getDeclaringClass().getName());
	CtMethod ctMethod = ctClass.getDeclaredMethod(method.getName());
	// 使用javassist的反射方法的参数名
	MethodInfo methodInfo = ctMethod.getMethodInfo();
	CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
	LocalVariableAttribute attr = (LocalVariableAttribute) 
		codeAttribute.getAttribute(LocalVariableAttribute.tag);

	int length = ctMethod.getParameterTypes().length;
	String[] array = new String[length];
	for (int i = 0; i < length; i++) {
		array[i] = attr.variableName(i + 1);
	}
	return array;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
public void rename(CtClass c) {
	for (CtBehavior behavior : c.getDeclaredBehaviors()) {
		
		// if there's a local variable table, just rename everything to v1, v2, v3, ... for now
		CodeAttribute codeAttribute = behavior.getMethodInfo().getCodeAttribute();
		if (codeAttribute == null) {
			continue;
		}
		
		BehaviorEntry behaviorEntry = EntryFactory.getBehaviorEntry(behavior);
		ConstPool constants = c.getClassFile().getConstPool();
		
		LocalVariableAttribute table = (LocalVariableAttribute)codeAttribute.getAttribute(LocalVariableAttribute.tag);
		if (table != null) {
			renameLVT(behaviorEntry, constants, table);
		}
		
		LocalVariableTypeAttribute typeTable = (LocalVariableTypeAttribute)codeAttribute.getAttribute(LocalVariableAttribute.typeTag);
		if (typeTable != null) {
			renameLVTT(typeTable, table);
		}
	}
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
private void initMethodParamInfo(Object controller, String methodName) {
	methodParamInfo = new LinkedHashMap<Class<?>, String>();
	Class<?> clazz = controller.getClass();
	try {
		ClassPool classPool = ClassPool.getDefault();
		classPool.insertClassPath(new ClassClassPath(clazz));
		CtClass ctClass = classPool.get(clazz.getName());
		CtMethod ctMethod = ctClass.getDeclaredMethod(methodName);

		MethodInfo methodInfo = ctMethod.getMethodInfo();
		CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
		LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute
				.getAttribute("LocalVariableTable");

		CtClass[] parameterTypes = ctMethod.getParameterTypes();
		int pos = Modifier.isStatic(ctMethod.getModifiers()) ? 0 : 1;
		for (int i = 0; i < parameterTypes.length; i++)
			methodParamInfo.put(Class.forName(parameterTypes[i].getName()),
					attr.variableName(i + pos));
	} catch (Exception e) {
		throw new RuntimeException(e.getMessage());
	}
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * Get method arg names.
 *
 * @param clazz
 * @param methodName
 * @return
 */
public static <T> String[] getMethodArgNames(Class<T> clazz, String methodName) {
    try {
        ClassPool pool = ClassPool.getDefault();
        CtClass cc = pool.get(clazz.getName());

        CtMethod cm = cc.getDeclaredMethod(methodName);

        // 使用javaassist的反射方法获取方法的参数名
        MethodInfo methodInfo = cm.getMethodInfo();
        CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
        LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
        if (attr == null) {
            throw new RuntimeException("LocalVariableAttribute of method is null! Class " + clazz.getName() + ",method name is " + methodName);
        }
        String[] paramNames = new String[cm.getParameterTypes().length];
        int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
        for (int i = 0; i < paramNames.length; i++)
            paramNames[i] = attr.variableName(i + pos);

        return paramNames;
    } catch (NotFoundException e) {
        throw new RuntimeException(e.getMessage(), e);
    }
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * Get method variable names for the provided method.
 * 
 * @param classname String
 * @param methodname String
 * @return the String[] of method variable name.
 */
public static String[] getMethodVariableName(String classname, String methodname) {
  try {
    ClassPool pool = ClassPool.getDefault();
    CtClass cc = pool.get(classname);
    CtMethod cm = cc.getDeclaredMethod(methodname);
    MethodInfo methodInfo = cm.getMethodInfo();
    CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
    String[] paramNames = new String[cm.getParameterTypes().length];
    LocalVariableAttribute attr =
        (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
    if (attr != null) {
      int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
      for (int i = 0; i < paramNames.length; i++) {
        paramNames[i] = attr.variableName(i + pos);
      }
      return paramNames;
    }
  } catch (Exception e) {
    throw new RuntimeException(e);
  }
  return null;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
public Subroutine[] scan(MethodInfo method) throws BadBytecode {
    CodeAttribute code = method.getCodeAttribute();
    CodeIterator iter = code.iterator();

    subroutines = new Subroutine[code.getCodeLength()];
    subTable.clear();
    done.clear();

    scan(0, iter, null);

    ExceptionTable exceptions = code.getExceptionTable();
    for (int i = 0; i < exceptions.size(); i++) {
        int handler = exceptions.handlerPc(i);
        // If an exception is thrown in subroutine, the handler
        // is part of the same subroutine.
        scan(handler, iter, subroutines[exceptions.startPc(i)]);
    }

    return subroutines;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
private static void insertAuxInitializer(CodeAttribute codeAttr,
                                         Bytecode initializer,
                                         int stacksize)
    throws BadBytecode
{
    CodeIterator it = codeAttr.iterator();
    int index = it.skipSuperConstructor();
    if (index < 0) {
        index = it.skipThisConstructor();
        if (index >= 0)
            return;         // this() is called.

        // Neither this() or super() is called.
    }

    int pos = it.insertEx(initializer.get());
    it.insert(initializer.getExceptionTable(), pos);
    int maxstack = codeAttr.getMaxStack();
    if (maxstack < stacksize)
        codeAttr.setMaxStack(stacksize);
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
protected void runEditor(ExprEditor ed, CodeIterator oldIterator)
    throws CannotCompileException
{
    CodeAttribute codeAttr = oldIterator.get();
    int orgLocals = codeAttr.getMaxLocals();
    int orgStack = codeAttr.getMaxStack();
    int newLocals = locals();
    codeAttr.setMaxStack(stack());
    codeAttr.setMaxLocals(newLocals);
    ExprEditor.LoopContext context
        = new ExprEditor.LoopContext(newLocals);
    int size = oldIterator.getCodeLength();
    int endPos = oldIterator.lookAhead();
    oldIterator.move(currentPos);
    if (ed.doit(thisClass, thisMethod, context, oldIterator, endPos))
        edited = true;

    oldIterator.move(endPos + oldIterator.getCodeLength() - size);
    codeAttr.setMaxLocals(orgLocals);
    codeAttr.setMaxStack(orgStack);
    maxLocals = context.maxLocals;
    maxStack += context.maxStack;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * Records local variables available at the specified program counter.
 * If the LocalVariableAttribute is not available, this method does not
 * record any local variable.  It only returns false.
 *
 * @param pc    program counter (>= 0)
 * @return false if the CodeAttribute does not include a
 *              LocalVariableAttribute.
 */
public boolean recordLocalVariables(CodeAttribute ca, int pc)
    throws CompileError
{
    LocalVariableAttribute va
        = (LocalVariableAttribute)
          ca.getAttribute(LocalVariableAttribute.tag);
    if (va == null)
        return false;

    int n = va.tableLength();
    for (int i = 0; i < n; ++i) {
        int start = va.startPc(i);
        int len = va.codeLength(i);
        if (start <= pc && pc < start + len)
            gen.recordVariable(va.descriptor(i), va.variableName(i),
                               va.index(i), stable);
    }

    return true;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * Records parameter names if the LocalVariableAttribute is available.
 * It returns false unless the LocalVariableAttribute is available.
 *
 * @param numOfLocalVars    the number of local variables used
 *                          for storing the parameters.
 * @return false if the CodeAttribute does not include a
 *              LocalVariableAttribute.
 */
public boolean recordParamNames(CodeAttribute ca, int numOfLocalVars)
    throws CompileError
{
    LocalVariableAttribute va
        = (LocalVariableAttribute)
          ca.getAttribute(LocalVariableAttribute.tag);
    if (va == null)
        return false;

    int n = va.tableLength();
    for (int i = 0; i < n; ++i) {
        int index = va.index(i);
        if (index < numOfLocalVars)
            gen.recordVariable(va.descriptor(i), va.variableName(i),
                               index, stable);
    }

    return true;
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
/**
 * This is basically the InstructionPrinter.getMethodBytecode but with a
 * CtBehaviour parameter instead of a CtMethod
 * 
 * @param behavior
 * @return
 */
public static String getBehaviourBytecode(CtBehavior behavior) {
    MethodInfo info = behavior.getMethodInfo2();
    CodeAttribute code = info.getCodeAttribute();
    if (code == null) {
        return "";
    }

    ConstPool pool = info.getConstPool();
    StringBuilder sb = new StringBuilder(1024);

    CodeIterator iterator = code.iterator();
    while (iterator.hasNext()) {
        int pos;
        try {
            pos = iterator.next();
        } catch (BadBytecode e) {
            throw new JVoidIntrumentationException("BadBytecoode", e);
        }

        sb.append(pos + ": " + InstructionPrinter.instructionString(iterator, pos, pool) + "\n");
    }
    return sb.toString();
}
 

import javassist.bytecode.CodeAttribute; //导入依赖的package包/类
public static String[] getReflectParamName(Class<?> clazz, String methodName) {
	String[] paramNames = null;
	try {
		ClassPool pool = ClassPool.getDefault();
		CtClass cc = pool.get(clazz.getName());
		CtMethod cm = cc.getDeclaredMethod(methodName);
		// 使用javaassist的反射方法获取方法的参数名
		MethodInfo methodInfo = cm.getMethodInfo();
		CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
		LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute.getAttribute(LocalVariableAttribute.tag);
		if (attr == null) {
			// exception
		}
		paramNames = new String[cm.getParameterTypes().length];
		int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
		for (int i = 0; i < paramNames.length; i++)
			paramNames[i] = attr.variableName(i + pos);
	} catch (NotFoundException e) {
		e.printStackTrace();
	}
	return paramNames;
}