package com.yys.screendisplay.controller;

import java.io.*;

import com.sun.org.apache.bcel.internal.classfile.ConstantString;
import org.gjt.jclasslib.io.ClassFileWriter;
import org.gjt.jclasslib.structures.ClassFile;
import org.gjt.jclasslib.structures.Constant;
import org.gjt.jclasslib.structures.constants.ConstantDoubleInfo;
import org.gjt.jclasslib.structures.constants.ConstantUtf8Info;
import org.gjt.jclasslib.structures.constants.ConstantStringInfo;
public class Test {
 public static void main(String[] args) throws Exception {

  String filePath = "C:\\Users\\HMS\\Desktop\\AppService.class";
  FileInputStream fis = new FileInputStream(filePath);

  DataInput di = new DataInputStream(fis);
  ClassFile cf = new ClassFile();
  cf.read(di);
  Constant[] infos = cf.getConstantPool();

  int count = infos.length;
  for (int i = 0; i < count; i++) {
   if (infos[i] != null) {
    if(i==1813){
     System.out.print(i);
     System.out.print(" = ");
     System.out.print(infos[i].getVerbose());
     System.out.print(" = ");
     System.out.println(infos[i]);
     System.out.println(infos[i].getClass().getSimpleName());
     ConstantUtf8Info uInfo = (ConstantUtf8Info)infos[i];//根據(jù)對(duì)應(yīng)的類型轉(zhuǎn)換
     uInfo.setString("");
     infos[i]=uInfo;
    }
   }
  }
  cf.setConstantPool(infos);
  fis.close();
  File f = new File(filePath);
  ClassFileWriter.writeToFile(f, cf);
 }
}

<dependency>
 <groupId>com.fasterxml.jackson.module</groupId>
  <artifactId>jackson-module-kotlin</artifactId>
 <version>2.9.4.1</version>
</dependency>