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javaweb简单二维码

2016-07-15 03:04 369 查看

webxml:

<servlet>

<servlet-name>AuthImageServlet</servlet-name>

<servlet-class>com.util.servlet.AuthImageServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>AuthImageServlet</servlet-name>

<url-pattern>/servlet/AuthImageServlet</url-pattern>

</servlet-mapping>

JSP：

<script type="text/javascript">

var random;

function changeCode(){

var imgNode = document.getElementById("vimg");



//重新加载验证码，达到刷新的目的

random = Math.random();



imgNode.src = "servlet/AuthImageServlet?t=" + random; // 防止浏览器缓存的问题

}

</script>

<body>

<form action="" method="post">

<label>输入验证码</label><br/>

<input type="text" name="randomCode"/><img id="vimg" title="点击更换" onclick="changeCode();" src="servlet/AuthImageServlet"><br/>



</form>

</body>

Servlet:

package com.util.servlet;

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.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

public class AuthImageServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/html; charset=gb2312";

//设置字母的大小,大小

private Font mFont = new Font("Times New Roman", Font.PLAIN, 17);

public void init() throws ServletException

{

super.init();

}

Color getRandColor(int fc,int bc)

{

Random random = new Random();

if(fc>255) fc=255;

if(bc>255) bc=255;

int r=fc+random.nextInt(bc-fc);

int g=fc+random.nextInt(bc-fc);

int b=fc+random.nextInt(bc-fc);

return new Color(r,g,b);

}



public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException

{

response.setHeader("Pragma","No-cache");

response.setHeader("Cache-Control","no-cache");

response.setDateHeader("Expires", 0);

//表明生成的响应是图片

response.setContentType("image/jpeg");

int width=100, height=18;

BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

Graphics g = image.getGraphics();

Random random = new Random();

g.setColor(getRandColor(200,250));

g.fillRect(1, 1, width-1, height-1);

g.setColor(new Color(102,102,102));

g.drawRect(0, 0, width-1, height-1);

g.setFont(mFont);



g.setColor(getRandColor(160,200));



//画随机线

for (int i=0;i<155;i++)

{

int x = random.nextInt(width - 1);

int y = random.nextInt(height - 1);

int xl = random.nextInt(6) + 1;

int yl = random.nextInt(12) + 1;

g.drawLine(x,y,x + xl,y + yl);

}



//从另一方向画随机线

for (int i = 0;i < 70;i++)

{

int x = random.nextInt(width - 1);

int y = random.nextInt(height - 1);

int xl = random.nextInt(12) + 1;

int yl = random.nextInt(6) + 1;

g.drawLine(x,y,x - xl,y - yl);

}



//生成随机数,并将随机数字转换为字母

String sRand="";

for (int i=0;i<6;i++)

{

int itmp = random.nextInt(26) + 65;

char ctmp = (char)itmp;

sRand += String.valueOf(ctmp);

g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));

g.drawString(String.valueOf(ctmp),15*i+10,16);

}

HttpSession session = request.getSession(true);

session.setAttribute("rand",sRand); //注意转换为字母的二维码字母char存在Session中可调取用于判断输入框和二维码是否相等



g.dispose();

ImageIO.write(image, "JPEG", response.getOutputStream());

}

}

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