ASM是一种Java字节码操纵框架,它允许我们在字节码中直接编辑Java程序,以支持自定义转换,优化和验证。如果想要编辑try-catch块的finally块,我们可以使用ASM Tree API。
以下是一个示例代码片段,在try-catch块的finally块上添加一条打印语句:
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.InsnNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class EditFinallyBlockExample {
public static void main(String[] args) throws IOException, NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
// 读取class文件的字节码
ClassReader cr = new ClassReader("TestClass");
ClassNode cn = new ClassNode();
cr.accept(cn, 0);
// 获取需要编辑的方法
MethodNode mn = (MethodNode)cn.methods.get(0);
// 使用ASM Tree API编辑finally块
InsnList insnList = new InsnList();
insnList.add(new MethodInsnNode(Opcodes.INVOKESTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;", false));
insnList.add(new InsnNode(Opcodes.LDC));
insnList.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/Object;)V", false));
insnList.add(new InsnNode(Opcodes.ATHROW));
mn.visitLabel(new Label());
mn.visitTryCatchBlock(mn.instructions.getFirst(), mn.instructions.getLast(), new Label(), "java/lang/Exception");
mn.visitLabel(new Label());
mn.visitTryCatchBlock(mn.instructions.getFirst(),
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