Struts2验证码

<div id="authCode">
    <input type="image" src="rand.action" onclick="changeValidateCode(this)"/>
</div>

<script type="text/javascript">
    function changeValidateCode(obj) {
        var currentTime= new Date().getTime();
        obj.src = "rand.action?d=" + currentTime;
    }
</script>

<package name="randpicture" extends="struts-default">
		<action name="rand" class="produceAuthCode">
			<result type="stream">
				<param name="contentType">image/jpeg</param>
				<param name="inputName">inputStream</param>
			</result>
		</action>	
	</package>

package com.demo.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;

/**
 * 
 * 生成验证码ACTION
 * 
 * 
 * */

public class ProduceAuthCode extends ActionSupport {

	private static final long serialVersionUID = 1L;
	
	private ByteArrayInputStream inputStream;

	public ByteArrayInputStream getInputStream() {
		return inputStream;
	}

	public void setInputStream(ByteArrayInputStream inputStream) {
		this.inputStream = inputStream;
	}

	@Override
	public String execute() throws Exception {
		// TODO Auto-generated method stub
		
		//在内存中创建对象
		int width=85; int height=20;
		BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
		
		//获取图形上下文
		Graphics g=image.getGraphics();
		
		//生成随即类
		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));
		
		//随即产生155条干扰线，使图像中的验证码不易被其他程序探测到
		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);
		}
		
		//去随机产生的验证码（6位数字）
		String sRand="";
		for(int i=0;i<6;i++){
			String rand=String.valueOf(random.nextInt(10));
			sRand+=rand;
			//将验证码显示在图像中
			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，所以只有直接生成
			g.drawString(rand, 13*i+6, 16);
		}
		
		//将验证码放入session
		ActionContext.getContext().getSession().put("rand", sRand);
		
		//图像生成
		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";
	}

	//给定范围获得随即颜色
	private Color getRandColor(int fc, int bc) {
		// TODO Auto-generated method stub
		Random random=new Random();
		if(fc>255)fc=255;
		if(bc>255)fc=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);
	}
}

ActionContext ctx=ActionContext.getContext();
		if(!CheckingCode.equals(ctx.getSession().get("rand"))){
			ctx.put("Msg", "验证码有误！");
			return "error";
		}