【发布时间】：2016-07-25 04:05:28
【问题描述】：
自从 5 天以来，我一直在与 ASM 斗争，但我无法解决我的问题。要求是从方法调用中获取作为参数传递的所有值。我知道有很多工具可以做到这一点。我选择了 ASM（我不知道我是否做出了正确的决定）
例如，如果我有这些方法
public void test2(String a, int b , String c, boolean ba, long d, String e){
}
public String giveMeAString(){
return "oneString";
}
public String giveMeAnotherString(){
return "anotherString";
}
public void test(){
test2("firstParameter", 2907, giveMeAString(),true, 1992, giveMeAnotherString());
}
我想保存 ["firstParameter",2907, "oneString", true, 1992, "anotherString"]
我已经阅读了这些主题：
How to get the return value in asm?
Java method parameters values in ASM
Tracing method invocation arguments in bytecode using ASM
get function arguments values using java asm for bytecode instrimentation
哪个解释了将参数放入局部变量，但我如何访问它们？
如何获得这些参数的值？我不明白我怎样才能得到那个参数。我不知道，例如打印它们。任何的想法？ 一旦它们在堆栈中，我不明白如何将值复制到变量中。
谢谢！
这是我正在使用的代码：
public static class ClassPrinterVisitor extends ClassVisitor {
private String name;
private String desc;
private String signature;
private Type[] paramTypes;
private boolean isStatic;
private String className;
private String methodName;
private String methodDesc;
private String owner;
private int access;
public ClassPrinterVisitor(int api, ClassVisitor cv) {
super(api, cv);
}
public ClassPrinterVisitor(int api) {
super(api);
}
@Override
public MethodVisitor visitMethod(int access, String name, String desc,
String signature, String[] exceptions) {
MethodVisitor oriMv = new MethodVisitor(Opcodes.ASM4) {
};
final MethodVisitor instMv2 = new MethodPrinterVisitor(access, desc, oriMv, Type.getArgumentTypes(desc), (access & Opcodes.ACC_STATIC) != 0, className,
name, desc);
return instMv2;
}
private class MethodPrinterVisitor extends MethodVisitor {
List<Object> params = new ArrayList<>();
List<Object> params2 = new ArrayList<>();
private Type[] paramTypes;
private boolean isStatic;
private String className;
private String methodName;
private String methodDesc;
public MethodPrinterVisitor(int api, MethodVisitor mv) {
super(api, mv);
}
public MethodPrinterVisitor(int access, String desc, MethodVisitor mv, Type[] paramTypes, boolean isStatic, String classname,
String methodname, String methoddesc) {
super(Opcodes.ASM4, mv);
this.paramTypes = paramTypes;
this.isStatic = isStatic;
this.className = classname;
this.methodName = methodname;
this.methodDesc = methoddesc;
}
@Override
public void visitLdcInsn(Object var1) {
if (var1 != null) {
params.add(var1);
super.visitLdcInsn(var1);
System.out.printf("arg: %s %n", var1.toString());
}
}
@Override
public void visitInsn(int var1) {
if(this.mv != null) {
this.mv.visitInsn(var1);
}
}
@Override
public void visitIntInsn(int var1, int var2) {
if(this.mv != null) {
this.mv.visitIntInsn(var1, var2);
}
}
@Override
public void visitVarInsn(int var1, int var2) {
if(this.mv != null) {
this.mv.visitVarInsn(var1, var2);
}
}
@Override
public void visitMethodInsn(int opcode, String owner, String name, String desc) {
Pattern pattern = Pattern.compile("[a-zA-Z0-9._]*");
System.out.printf("---------------------------%n");
System.out.printf("Class %s calls method %s from class %s%n", ClassPrinterVisitor.this.name, name, owner);
System.out.printf("Desc: %s signature: %s%n", ClassPrinterVisitor.this.desc, ClassPrinterVisitor.this.signature);
for (Object p : params) {
Matcher matcher = pattern.matcher(p.toString());
if (!p.toString().isEmpty() && !p.toString().startsWith(".") && matcher.matches()) {
System.out.printf("visitLdcInsn: %s %n", p);
}
}
System.out.printf("---------------------------%n%n");
params = new ArrayList<>();
}
@Override
public void visitCode() {
int paramLength = paramTypes.length;
// Create array with length equal to number of parameters
mv.visitIntInsn(Opcodes.BIPUSH, paramLength);
mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
mv.visitVarInsn(Opcodes.ASTORE, paramLength);
// Fill the created array with method parameters
int i = 0;
for (Type tp : paramTypes) {
mv.visitVarInsn(Opcodes.ALOAD, paramLength);
mv.visitIntInsn(Opcodes.BIPUSH, i);
if (tp.equals(Type.BOOLEAN_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "valueOf", "(Z)Ljava/lang/Boolean;");
} else if (tp.equals(Type.BYTE_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Byte", "valueOf", "(B)Ljava/lang/Byte;");
} else if (tp.equals(Type.CHAR_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Character", "valueOf", "(C)Ljava/lang/Character;");
} else if (tp.equals(Type.SHORT_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Short", "valueOf", "(S)Ljava/lang/Short;");
} else if (tp.equals(Type.INT_TYPE)) {
mv.visitVarInsn(Opcodes.ILOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Integer", "valueOf", "(I)Ljava/lang/Integer;");
} else if (tp.equals(Type.LONG_TYPE)) {
mv.visitVarInsn(Opcodes.LLOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Long", "valueOf", "(J)Ljava/lang/Long;");
i++;
} else if (tp.equals(Type.FLOAT_TYPE)) {
mv.visitVarInsn(Opcodes.FLOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Float", "valueOf", "(F)Ljava/lang/Float;");
} else if (tp.equals(Type.DOUBLE_TYPE)) {
mv.visitVarInsn(Opcodes.DLOAD, i);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Double", "valueOf", "(D)Ljava/lang/Double;");
i++;
} else
mv.visitVarInsn(Opcodes.ALOAD, i);
mv.visitInsn(Opcodes.AASTORE);
i++;
}
// Load id, class name and method name
this.visitLdcInsn(new Integer(this.methodID));
this.visitLdcInsn(this.className);
this.visitLdcInsn(this.methodName);
// Load the array of parameters that we created
this.visitVarInsn(Opcodes.ALOAD, paramLength);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, className, name, signature);
super.visitCode();
}
}
}
【问题讨论】：