1.三要素

(1) 入口 就是我们所在的页面

入口到处理的数据请求会出现乱码，用request.SetCharacterEncoding("UTF-8");来解决，仅仅是用用于Post请求。

(2)处理 就是在Servlet中执行的内容

处理到出口之间也会出现乱码，用response.SetCharacterEncoding("UTF-8")来解决

(3)出口  就是我们跳转的页面

web.xml配置如下

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

LoginServlet

com.beiwo.servlet.LoginServlet

LoginServlet

/LoginServlet

index.jsp

2.首先写一个登录界面

Login.html

账号：

密码：

//当我们将鼠标放置登录按钮上面时会出现用户名跟密码，不安全

登录

3.点击登录之后会进入servlet

package com.beiwo.servlet;

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;

public class LoginServlet extends HttpServlet {

/**

* Constructor of the object.

*/

public LoginServlet() {

super();

}

/**

* Destruction of the servlet.

*/

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

// Put your code here

}

/**

* The doGet method of the servlet.

*

* This method is called when a form has its tag value method equals to get.

*

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

*/

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

System.out.println("进入了doGet方法");

String name = request.getParameter("username");

String password = request.getParameter("pwd");

System.out.println("用户名：" + name + "密码：" + password);

request.setAttribute("username", name);

request.setAttribute("pwd", password);

//跳转并且传递参数

request.getRequestDispatcher("Success.jsp").forward(request, response);

//html文件不能够传递参数，只有jsp文件可以传递参数

//跳转不带参数

response.sendRedirect("Success.jsp");

}

/**

* The doPost method of the servlet.

*

* This method is called when a form has its tag value method equals to post.

*

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

*/

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

System.out.println("进入了doPost方法");

//拿到用户名和密码

String name = request.getParameter("username");

String password = request.getParameter("pwd");

System.out.println("用户名：" + name + "密码：" + password);

//保存用户名和密码

request.setAttribute("username", name);

request.setAttribute("pwd", password);

//跳转并且传递参数

request.getRequestDispatcher("Success.jsp").forward(request, response);

//跳转不带参数

//response.sendRedirect("Success.jsp");

}

/**

* Initialization of the servlet.

*

* @throws ServletException if an error occurs

*/

public void init() throws ServletException {

// Put your code here

}

}

4.跳转到另外一个页面，并且拿到 用户名跟密码

//在这里首先要将编码格式改为utf-8，否则会出现乱码

Success.html

//当我们拿数据的时候要用${}

用户名：${username} 密码:${pwd}