servlet 传值给 jsp

java

package helloworld;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class HelloWorld
 */
@WebServlet("/HelloWorld")
public class HelloWorld extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public HelloWorld() {
        // TODO Auto-generated constructor stub

    
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

            doPost(request,response);
    
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        
        
          response.setContentType("text/html; charset=gb2312"); //设置网页的字符编码格式为gb2312
          request.setAttribute("msg", "123345");  //类似<key,value>，用于请求的参数传递，一般是action到jsp界面
request.getRequestDispatcher("msg.jsp").forward(request,response);//当你要跳转页面但是你又要用到前一个页面的某些信息的时候可以用这个方法
//当你要跳转页面并且不需要用到前一个页面的信息时你可以选择用redirect（重定向）


 } }

jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
    <%@ page import="java.util.List" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%=request.getAttribute("msg") %>
</body>
</html>

xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>helloworld</display-name>
  <servlet>
    <servlet-name>Register</servlet-name>
    <servlet-class>helloworld.HelloWorld</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Register</servlet-name>
    <url-pattern>/Register</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>
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原文地址：https://www.cnblogs.com/hellowzd/p/4700287.html