Struts 2 验证码

JavaScript 脚本

//验证码

function changeValidateCode(obj) {

//获取当前的时间作为参数，无具体意义

var timenow = new Date().getTime();

//每次请求需要一个不同的参数，否则可能会返回同样的验证码

//这和浏览器的缓存机制有关系，也可以把页面设置为不缓存，这样就不用这个参数了。

obj.src="rand.action?d="+timenow;

}

jsp页面 

    <img src="rand.action" οnclick="changeValidateCode(this)"/>

Action 类

package com.zhanggaosong.action;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.imageio.stream.ImageOutputStream;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class RandomAction extends ActionSupport {

private static final long serialVersionUID = 1L;

private ByteArrayInputStream inputStream;

public String execute() throws Exception{

// 在内存中创建图象

int width=60, height=25;

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

// 获取图形上下文

Graphics g = image.getGraphics();

// 生成随机类

Random random = new Random();

// 设定背景色

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

g.fillRect(0, 0, width, height);

// 设定字体

g.setFont(new Font("Times New Roman",Font.PLAIN,18));

// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到

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

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

{

int x = random.nextInt(width);

int y = random.nextInt(height);

int xl = random.nextInt(12);

int yl = random.nextInt(12);

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

}

// 取随机产生的认证码(4位数字)

String sRand="";

for (int i=0;i<4;i++){

String rand=String.valueOf(random.nextInt(10));

sRand+=rand;

// 将认证码显示到图象中

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

// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成

g.drawString(rand,13*i+6,16);

}

// 将认证码存入SESSION

ActionContext.getContext().getSession().put("rand",sRand);

// 图象生效

g.dispose();

ByteArrayOutputStream output = new ByteArrayOutputStream();

ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);

ImageIO.write(image, "JPEG", imageOut);

imageOut.close();

ByteArrayInputStream input = new ByteArrayInputStream(output.toByteArray());

this.setInputStream(input);

return SUCCESS;

}

/*

* 给定范围获得随机颜色

*/

private 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 setInputStream(ByteArrayInputStream inputStream) {

this.inputStream = inputStream;

}

public ByteArrayInputStream getInputStream() {

return inputStream;

}

}

Struts 配置文件

<action name="rand" class="com.zhanggaosong.action.RandomAction">

<result type="stream">

<param name="contentType">image/jpeg</param>

<param name="inputName">inputStream</param>

</result>

</action>