周六 requese中文乱码

package com.itheima.web.request;


import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

/**
 * 中文乱码问题解决方案
 */
@WebServlet("/req4")
public class RequestDemo4 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1. 解决乱码：POST，getReader()
        //request.setCharacterEncoding("UTF-8");//设置字符输入流的编码

        //2. 获取username
        String username = request.getParameter("username");
        System.out.println("解决乱码前："+username);

        //3. GET,获取参数的方式：getQueryString
        // 乱码原因：tomcat进行URL解码，默认的字符集ISO-8859-1
       /* //3.1 先对乱码数据进行编码：转为字节数组
        byte[] bytes = username.getBytes(StandardCharsets.ISO_8859_1);
        //3.2 字节数组解码
        username = new String(bytes, StandardCharsets.UTF_8);*/

        username  = new String(username.getBytes(StandardCharsets.ISO_8859_1),StandardCharsets.UTF_8);

        System.out.println("解决乱码后："+username);

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}