How to solve the Mysql transaction operation failure

 private void testCrud() {
     Connection conn = null; //Connection object PreparedStatement pstmt = null; //Precompiled SQL statement object try{
        //Load MySQL driver Class.forName("com.mysql.jdbc.Driver");
        //Connection string String url = "jdbc:mysql://localhost:3306/test";
        //Establish database connection conn = DriverManager.getConnection(url,"root","");
        //Set the transaction isolation level // conn.setTransactionIsolation(Connection. TRANSACTION_REPEATABLE_READ);
        //Set autocommit to false and start transaction conn.setAutoCommit(false);
        //Update statement with parameters String sql = "INSERT INTO user_info (username ,password ,age )values(?,?,?)";
        //Prepare statement pstmt = conn.prepareStatement(sql);
        //Bind parameters, execute update statement, and subtract 1000 yuan from Zhang San's account balance pstmt.setString(1, "zhangui");
        pstmt.setString(2, "1111");
        pstmt.setInt(3, 300);
        pstmt.execute();
        
        //Bind parameters, execute update statement, and increase the balance of Li Si's account by 1,000 yuan// pstmt.setString(1, "zzzzzzzzzzzzzzzzz"); //Illegal parameters are bound//pstmt.setString(2, "1111111111");
        //pstmt.setInt(3, 500);
        //pstmt.execute(); //SQL exception will be thrown //Commit the transaction //conn.commit();
        System.out.println("Transaction submitted, transfer successful!");
        //Close statement, connection pstmt.close(); conn.close();
      }catch(Exception e){
        try{
          conn.rollback(); //Rollback transaction System.out.println("Transaction rolled back successfully, no records were updated!");
        }catch(Exception re){
          System.out.println("Rollback transaction failed!");
        }
        e.printStackTrace();
      }finally{
        if(pstmt!=null) try{pstmt.close();}catch(Exception ignore){}
        if(conn!=null) try{conn.close();}catch(Exception ignore){}
      }
    
  }