系统登录界面的验证码
一、java后台生成随机验证码
package com.code;
import java.awt.Color;
import java.awt.Font;
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.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@SuppressWarnings("serial")
public class Check extends HttpServlet {
public String suijima(){
char [] str="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();
Random rd=new Random();
String suiji="";
int temp=0;
for(int i=0;i<4;i++){
temp=rd.nextInt(36);
suiji+=str[temp];
}
return suiji;
}
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String sjm=suijima();
HttpSession session=request.getSession();
session.setAttribute("check",sjm); //在登录验证的时候会首先检查验证码是否输入正确
BufferedImage buffimg=new BufferedImage(60,20,BufferedImage.TYPE_INT_RGB);
Graphics g=buffimg.createGraphics();
Random rd=new Random();
int cr,cg,cb;
cr=rd.nextInt(255);
cg=rd.nextInt(255);
cb=rd.nextInt(255);
Color mycolor=new Color(cr,cg,cb);
//干扰线
g.setColor(mycolor);
for (int i = 0; i < 10; i++){
int x1 = rd.nextInt(60);
int x2 = rd.nextInt(60);
int y1 = rd.nextInt(20);
int y2 = rd.nextInt(20);
g.drawLine(x1, y1, x2, y2);
}
//显示随机码
Font myfont=new Font("times new roman",Font.PLAIN,19);
g.setFont(myfont);
g.setColor(Color.WHITE);
g.drawString(sjm,5,15);
//将图像输出到servlet输出流中。
ServletOutputStream sos=response.getOutputStream();
ImageIO.write(buffimg, "jpeg",sos);
sos.close();
g.dispose();
}
}
二、jsp页面，用jquery验证
<body>
<form method="post">
用户名：<input type="text" name="username" id="username"/> <br>
密 码： <input type="password" name="pwd" id="pwd"/><br>
验证码:<input type="text" name="yzm" id="yzm"/>
<img id="code" src="http://localhost:8080/javacode/check.do" onclick="javascript:change()" title="点击刷新验证码"><br>
<input type="button" onclick="check()" value="登录"/>
<input type="reset" name="reset" value="重置" />
<div id="result"></div>
</form>
</body>
<script language="javascript">
function check()
{
var jqueryobj = $("#username");
var username = jqueryobj.val();
var jqueryobj1 = $("#pwd");
var pwd = jqueryobj1.val();
var jqueryobj2 = $("#yzm");
var yzm = jqueryobj2.val();
var object =username+","+pwd+","+yzm;
$.get("checkcode.do?object="+object,null,callback);
}
function callback(data){
if(data==1){
data = "验证码出错，请重新输入！";
}else if(data==2){
data = "验证码正确！";
}
var resultObj = $("#result");
resultObj.html("<font color=red>"+data+"</font>");
}
function change(){
var dt = new Date();
var img=document.getElementById("code");
img.src="http://localhost:8080/javacode/check.do?dt"+dt; //意思是让图片重新加载一次 效果类似与直接刷新yanzhengma.jsp有了这个，就能让图片重新加载了
}
</script>
</html>
三、后台验证
package com.code;
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;
@SuppressWarnings("serial")
public class Checkcode extends HttpServlet{
public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException{
String strYzm=request.getParameter("object"); //用户输入的验证码
String [] str = strYzm.split(",");
String stryz=(String)request.getSession().getAttribute("check"); //servlet中生成的验证码
int error;
response.setContentType("text/html;charset=GBK");
str[2]=str[2].toUpperCase();
PrintWriter out=response.getWriter();
if(!str[2].equals(stryz)){
error=1;
}else{
error=2;
}
out.println(error);
}
public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException{
doPost(request,response);
}
}
这样就可以完成登录页面的验证！
