<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <%-- 1.创建登录界面，用户名，密码，验证码，登录按钮 2.servlet生成验证码，存入session，并实现点击刷新 3.登录按钮跳转到servlet判断界面 4.先判断验证码是否正确，再判断用户名和密码 5.正确登录进入登录成功界面，不正确返回登录界面并清除session验证码防止重用 6.删除session对象，退出 --%> <meta charset="utf-8"> <title>用户登录</title> <style type="text/css"> span{ text-decoration:underline; color:blue; } div{ color: red; } </style> </head> <script type="text/javascript"> window.onload=function(){ var i=0; var yzm=document.getElementById("yzm"); yzm.onclick=function(){ i++; yzm.src="/web_homework2/yzm?"+i; } var span=document.getElementById("span"); span.onclick=function(){ yzm.onclick(); } } </script> <body> <form action="/web_homework2/testServlet" method="post"> <input type="text" id="username" name="username" placeholder="你确定不输入yxy?"><br> <input type="password" id="password" name="password" placeholder="你确定不输入123456?"><br> <input type="text" name="yzm_text" placeholder="看清图片再输入"><br> <img alt="这是一张验证码" src="/web_homework2/yzm" id="yzm"><span id="span">啥玩意啊！换一个</span><br> <input type="submit" value="登录"> </form> <div><%=request.getSession().getAttribute("yzm_error")==null?"":request.getSession().getAttribute("yzm_error")%></div> <div><%=request.getSession().getAttribute("user_error")==null?"":request.getSession().getAttribute("user_error")%></div> <%request.getSession().removeAttribute("yzm_error"); request.getSession().removeAttribute("user_error"); %> </body> </html>
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>欢迎登录</title> </head> <script type="text/javascript"> window.onload=function(){ var zx=document.getElementById("zx"); zx.onclick=function(){ alert("你要走了吗？"); document.getElementById("a").href="/web_homework2/exit"; } } </script> <body> <% String name=(String)request.getSession().getAttribute("name"); %> <p>欢迎登录，<%=name %>你是最酷的</p><br> <a id="a" href="#"><input type="submit" value="注销" id="zx"></a> </body> </html>
package servlet; import java.awt.Color; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class yzm */ @WebServlet("/yzm") public class yzm extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public yzm() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //创建图片对象 int width=100; int height=50; BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR); //获取画笔 Graphics g = image.getGraphics(); //填充背景颜色 g.setColor(Color.PINK); g.fillRect(0, 0, width, height); //画蓝色边框 g.setColor(Color.BLUE); g.drawRect(0, 0, width-1, height-1); //生成随机字母数字,利用循环写入，同时保存session String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; Random r = new Random(); g.setColor(Color.RED);//红色字 StringBuilder sBuilder=new StringBuilder(); for (int i = 0; i < 4; i++) { int index = r.nextInt(str.length()); char ch = str.charAt(index); g.drawString(ch+"", width/5+i*20, height/2);//调整位置 sBuilder.append(ch); } String yzm_session = sBuilder.toString(); request.getSession().setAttribute("yzm_session", yzm_session); //画干扰线绿色 g.setColor(Color.GREEN); for (int i = 0; i < 10; i++) { int x1 = r.nextInt(width); int x2 = r.nextInt(width); int y1 = r.nextInt(height); int y2 = r.nextInt(height); g.drawLine(x1, y1, x2, y2); } //输出图像展示到网页 ImageIO.write(image, "jpg", response.getOutputStream()); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
package servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; /** * Servlet implementation class TestServlet */ @WebServlet("/testServlet") public class TestServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public TestServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub request.setCharacterEncoding("utf-8"); HttpSession session = request.getSession(); String yzm = (String)session.getAttribute("yzm_session"); session.removeAttribute("yzm_session");//防止验证码复用 String yzm_text = request.getParameter("yzm_text"); if(yzm_text.equalsIgnoreCase(yzm)) { //验证码正确，继续判断用户名和密码 String username = request.getParameter("username"); String password = request.getParameter("password"); if(username.equals("yxy")&&password.equals("123456")) { //验证成功，跳转到登录成功界面 request.getSession().setAttribute("name", username); request.getRequestDispatcher("/loginSuccess.jsp").forward(request,response); }else { //验证失败，返回登录界面，并提示错误信息 request.getSession().setAttribute("user_error", "用户名或密码错误！"); request.getRequestDispatcher("/login.jsp").forward(request, response); } }else { //验证码错误，返回登录界面，并提示错误信息 request.getSession().setAttribute("yzm_error", "验证码错误！"); request.getRequestDispatcher("/login.jsp").forward(request, response); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
package servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class exit */ @WebServlet("/exit") public class exit extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public exit() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub request.getSession().invalidate();//终结session request.getRequestDispatcher("/login.jsp").forward(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }