Struts2Mvc驗證碼

在struts2中驗證碼無法在action中生成，只能通過servlet來生成。

1、創建驗證碼servlet

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
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;

public class RandCodeServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//設置頁面不緩存
		response.setHeader("Pragma","No-cache");
		response.setHeader("Cache-Control","no-cache");
		response.setDateHeader("Expires", 0);
		// 在內存中創建圖象
		int width=130, height=40;
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		// 獲取圖形上下文
		Graphics2D g = image.createGraphics(); 
		//生成隨機類
		Random random = new Random();
		// 設定背景色
		g.setColor(getRandColor(200,250));
		g.fillRect(0, 0, width, height);
		//設定字體
		g.setFont(new Font("Fixedsys",Font.PLAIN,38));
		//畫邊框
		//g.setColor(new Color());
		//g.drawRect(0,0,width-1,height-1);
		// 隨機產生155條幹擾線，使圖象中的認證碼不易被其它程序探測到
		g.setColor(getRandColor(160,200));
		for (int i=0;i<255;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);
		}
		// 取隨機產生的認證碼(4位數字)
		String sRand="";
		for (int i=0;i<4;i++){
		    String rand=String.valueOf(random.nextInt(10));
		    sRand+=rand;
		    
		    // 將認證碼顯示到圖象中
		    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
		//調用函數出來的顏色相同，可能是因爲種子太接近，所以只能直接生成
			rand += "  ";
		    g.drawString(rand,30*i+16,36);
		}
		request.getSession().setAttribute("YZM",sRand);
		// 圖象生效
		g.dispose();
		// 輸出圖象到頁面
		ImageIO.write(image, "JPEG", response.getOutputStream());
		response.getOutputStream().flush();
		response.getOutputStream().close();
	}
	

	private static Color getRandColor(int fc,int bc){//給定範圍獲得隨機顏色
        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);
    }
}

2、web.xml配置

<servlet> 
	<servlet-name>RandCodeServlet</servlet-name> 
	<servlet-class>com.col.sesame.common.util.RandCodeServlet</servlet-class> 
</servlet> 
<servlet-mapping> 
	<servlet-name>RandCodeServlet</servlet-name> 
	<url-pattern>/RandCodeServlet</url-pattern> 
</servlet-mapping>