剛做了一個登陸介面，用了WebServlet註解，發現驗證碼怎麼也重新整理不了，除錯之後發現根本沒有進入驗證碼生成的方法中去。這是我想肯定是註解或者XML檔案出問題了。我用了原始的在XML檔案中配置servlet.

<servlet>
<servlet-name>verifyCode</servlet-name>
<servlet-class>cn.sh.ideal.util.VerifyCode</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>verifyCode</servlet-name>
<url-pattern>/VerifyCode</url-pattern><!--這個和src的名字一樣-->
</servlet-mapping>
 

package cn.sh.ideal.util;

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.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

//@WebServlet("/verifyCode")
public class VerifyCode extends HttpServlet {
	 
	private static final long serialVersionUID = 7819264488896491500L;
	
	private static Logger logger = Logger.getLogger(VerifyCode.class);

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

	protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
		 
		System.out.println("進來了");
		String data = "0123456789";
		 
		Random random = new Random();

		int width = 60;  
		
		int height = 30; 

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

		Graphics2D g = (Graphics2D) image.getGraphics();

		g.setColor(Color.GREEN);

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

		g.setColor(Color.WHITE);

		g.fillRect(1, 1, width -1, height - 3);

		g.setFont(new Font("宋體", Font.PLAIN, 20));

		StringBuilder builder = new StringBuilder(); 

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

			g.setColor(new Color(24, 88,129));

			int index = random.nextInt(data.length());
			
			String str = data.substring(index, index + 1);

			builder.append(str);
			
			g.rotate(Math.PI / 150, 1, 1);
			
			g.drawString(str, (i + 1) * (width / 5), 13);
		}
		
		//logger.info(builder.toString());

		request.getSession().setAttribute("identiCodeInSession",builder.toString());

		for (int i = 0; i < 5; i++) {

			g.setColor(new Color(random.nextInt(255), random.nextInt(255),random.nextInt(255)));

			g.drawLine(random.nextInt(width), random.nextInt(height),random.nextInt(width), random.nextInt(height));
		}
		
		response.setHeader("Pragma", "no-cache");    
		
		response.setHeader("Cache-Control", "no-cache"); 
		
		response.setDateHeader("Expires", 0);      

		ImageIO.write(image, "jpeg", response.getOutputStream());
 
	}

}
 

註釋web.xml檔案中的servlet配置，然後取消@Webservlet註解的註釋。發現可以完美生成驗證碼。