final String signature, final String superName,
final String[] interfaces) {
String enhancedName = name + "$EnhancedByASM"; //改变类命名
enhancedSuperName = name; //改变父类，这里是”Account”
super.visit(version, access, enhancedName, signature,
enhancedSuperName, interfaces);
}
改进 visitMethod 方法，增加对构造函数的处理：
public MethodVisitor visitMethod(final int access, final String name,
final String desc, final String signature, final String[] exceptions) {
MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions);
MethodVisitor wrappedMv = mv;
if (mv != null) {
if (name.equals("operation")) {
wrappedMv = new AddSecurityCheckMethodAdapter(mv);
} else if (name.equals("<init>")) {
wrappedMv = new ChangeToChildConstructorMethodAdapter(mv,
enhancedSuperName);
}
}
return wrappedMv;
}
这里 ChangeToChildConstructorMethodAdapter 将负责把 Account 的构造函数改造成其子类 Account$EnhancedByASM 的构造函数
Account$EnhancedByASM 的构造函数：
class ChangeToChildConstructorMethodAdapter extends MethodAdapter {
private String superClassName;
public ChangeToChildConstructorMethodAdapter(MethodVisitor mv,
String superClassName) {
super(mv);
this.superClassName = superClassName;
}
public void visitMethodInsn(int opcode, String owner, String name,
String desc) {
//调用父类的构造函数时
if (opcode == Opcodes.INVOKESPECIAL && name.equals("<init>")) {
owner = superClassName;
}
super.visitMethodInsn(opcode, owner, name, desc);//改写父类为superClassName
}
}
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