java中form以post、get方式提交数据中文乱码问题总结

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//以post方式提交表单
public class RequestDemo extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
         //请求数据的中文乱码问题
        request.setCharacterEncoding("UTF-8");//客户端网页我们控制为UTF-8
        String username = request.getParameter("username");
        //获取数据正常，输出数据时可以查阅不同码表
        response.setCharacterEncoding("gb2312");//通知服务器发送数据时查阅的码表
        response.setContentType("text/html;charset=gb2312");//通知浏览器以何种码表打开
        PrintWriter out = response.getWriter();
        out.write(username);
} 

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request,response);
}

   public void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
        //请求数据的中文乱码问题
       request.setCharacterEncoding("UTF-8");//以get方式提交数据时，request设置编码无效。即使设置了UTF-8还是会去查ISO8859-1
       String username = request.getParameter("username");
      System.out.println(username);
       byte source [] = username.getBytes("iso8859-1");
       username = new String (source,"UTF-8");
       System.out.println(username);
      
} 

   public void doPost(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       doGet(request,response);
}

}