SERVLET登陆注册
package com.itheima.servlet; import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayList; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LoginServlet extends HttpServlet { /** * request : 包含请求的信息 * * response : 响应数据给浏览器, 就靠这个对象 */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1. 获取数据 String userName = request.getParameter("username"); String password = request.getParameter("password"); System.out.println("userName="+userName+"==password="+password); //2. 校验数据 //向客户端输出内容 PrintWriter pw = response.getWriter(); if("admin".equals(userName) && "123".equals(password)){ //System.out.println("登录成功"); // pw.write("login success.."); //成功就跳转到login_success.html //1. 成功的次数累加 //获取以前存的值 , 然后在旧的值基础上 + 1 Object obj = getServletContext().getAttribute("count") ; //默认就是0次 int totalCount = 0 ; if(obj != null){ totalCount = (int) obj; } System.out.println("已知登录成功的次数是:"+totalCount); //给这个count赋新的值 getServletContext().setAttribute("count", totalCount+1); //2. 跳转到成功的界面 //设置状态码? 重新定位 状态码 response.setStatus(302); //定位跳转的位置是哪一个页面。 response.setHeader("Location", "login_success.html"); }else{ pw.write("login failed.."); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
package com.itheima.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class CountSrevlet */ public class CountSrevlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1. 取值 int count = (int) getServletContext().getAttribute("count"); //2. 输出到界面 response.getWriter().write("login success count ===:"+count); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }