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web实现图形验证功能

2012-12-30 00:27 435 查看

这里直接上工程文件源码：

ValidateImage.java:

package jpeg;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ValidateImage extends HttpServlet {
	
	protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
	    response.setContentType("image/jpeg");
	    createImage(response.getOutputStream());
	    response.setHeader("Pragma","No-cache");
	    response.setHeader("Cache-Control","no-cache");
	    response.setDateHeader("Expires", 0);
	}
	
	private void createImage(OutputStream out)throws IOException	{
		int width=60, height=20;
		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(0, 0, width, height);
		g.setFont(new Font("Times New Roman",1,15));
		//g.setColor(new Color());
		//g.drawRect(0,0,width-1,height-1);
		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);
		}
		//String rand = request.getParameter("rand");
		//rand = rand.substring(0,rand.indexOf("."));
		String sRand="";
		for (int i=0;i<4;i++){
		    String rand=String.valueOf(random.nextInt(10));
		    sRand+=rand;
		    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
		    g.drawString(rand,13*i+6,16);
		}
              //session.setAttribute("rand",sRand);
		g.dispose();
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
		JPEGEncodeParam param 	= encoder.getDefaultJPEGEncodeParam(image);
		param.setQuality(1.0f, false);
		encoder.setJPEGEncodeParam(param);
		try{
			encoder.encode(image);
		}catch (IOException ioe){
			ioe.printStackTrace();
		}
	}
	
	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);
        }
		
}

TestImage.jsp:

<body>
    <img src="validate"> <br>
  </body>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">   <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>ValidateImage</servlet-name>
    <servlet-class>jpeg.ValidateImage</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>ValidateImage</servlet-name>
    <url-pattern>/validate</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

地址栏：http://localhost:8080/JPEG/jsp/TestImage.jsp 结果：

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