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="/xml/ns/javaee"
xmlns:xsi="/2001/XMLSchema-instance"
xsi:schemaLocation="/xml/ns/javaee
/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}
