參考了幾篇文章,，寫了個用servlet生產(chǎn)唯一驗證碼(改造了原作者代碼,，在此致謝，后附鏈接),。附件是可直接使用的工程,。明天試用一個開源項目，可以比較方便的生成各種風(fēng)格的驗證碼,，甚至還有聲音,，比較有意思。第一次記錄自己的學(xué)習(xí),，以后爭取每天寫一點,。
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Java代碼

1. package com.stone.study.validate;   
2.   
3. import java.awt.Color;   
4. import java.awt.Font;   
5. import java.awt.Graphics;   
6. import java.awt.image.BufferedImage;   
7. import java.io.ByteArrayOutputStream;   
8. import java.io.IOException;   
9.   
10. import javax.imageio.ImageIO;   
11. import javax.servlet.ServletException;   
12. import javax.servlet.ServletOutputStream;   
13. import javax.servlet.http.HttpServlet;   
14. import javax.servlet.http.HttpServletRequest;   
15. import javax.servlet.http.HttpServletResponse;   
16. import javax.servlet.http.HttpSession;   
17.   
18. public class ImgValidateServlet2 extends HttpServlet {   
19.     private static int WIDTH = 90;   
20.     private static int HEIGHT = 20;   
21.     private static int LENGTH = 6;   
22.   
23.     @Override  
24.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   
25.          HttpSession session = request.getSession();   
26.   
27.          response.setContentType("image/jpeg");   
28.   
29.          ServletOutputStream sos = response.getOutputStream();   
30.   
31.          //設(shè)置瀏覽器不要緩存此圖片   
32.          response.setHeader("Pragma","No-cache");   
33.          response.setHeader("Cache-Control","no-cache");   
34.          response.setDateHeader("Expires", 0);   
35.   
36.          //創(chuàng)建內(nèi)存圖象并獲得其圖形上下文   
37.          BufferedImage image =    
38.                 new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);    
39.   
40.          Graphics g = image.getGraphics();   
41.   
42.          //產(chǎn)生隨機(jī)的認(rèn)證碼   
43.          char [] rands = generateCheckCode();   
44.   
45.          //產(chǎn)生圖像   
46.          drawBackground(g);   
47.   
48.          drawRands(g,rands);   
49.   
50.          //結(jié)束圖像的繪制過程，完成圖像   
51.          g.dispose();   
52.   
53.          //將圖像輸出到客戶端   
54.          ByteArrayOutputStream bos = new ByteArrayOutputStream();   
55.   
56.          ImageIO.write(image, "JPEG", bos);   
57.   
58.          byte [] buf = bos.toByteArray();   
59.   
60.          response.setContentLength(buf.length);   
61.   
62.          //下面的語句也可寫成：bos.writeTo(sos);   
63.          sos.write(buf);   
64.          bos.close();   
65.          sos.close();   
66.   
67.          //將當(dāng)前驗證碼存入到Session或者數(shù)據(jù)庫中,下一個表單處理中驗證客戶端提交的驗證碼是否正確   
68.          session.setAttribute("check_code",new String(rands));   
69.     }   
70.   
71.     private static char [] generateCheckCode()   
72.     {   
73.        //定義驗證碼的字符表   
74.        String chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";   
75.   
76.        char [] rands = new char[LENGTH];   
77.        for(int i=0; i<LENGTH; i++)   
78.   
79.        {   
80.           int rand = (int)(Math.random() * 36);   
81.           rands[i] = chars.charAt(rand);   
82.        }   
83.   
84.        return rands;   
85.     }   
86.        
87.        private void drawRands(Graphics g , char [] rands)    
88.        {   
89.           g.setColor(Color.BLACK);   
90.           g.setFont(new Font(null,Font.ITALIC|Font.BOLD,18));   
91.   
92.           //在不同的高度上輸出驗證碼的每個字符            
93.           g.drawString("" + rands[0],1,17);   
94.           g.drawString("" + rands[1],16,15);   
95.           g.drawString("" + rands[2],31,18);   
96.           g.drawString("" + rands[3],46,16);   
97.           g.drawString("" + rands[4],61,14);   
98.           g.drawString("" + rands[5],76,19);   
99.   
100.           System.out.println(rands);   
101.        }   
102.   
103.        private void drawBackground(Graphics g)   
104.   
105.        {   
106.            //畫背景   
107.           g.setColor(new Color(0xDCDCDC));   
108.           g.fillRect(0, 0, WIDTH, HEIGHT);   
109.   
110.           //隨機(jī)產(chǎn)生120個干擾點   
111.           for(int i=0; i<120; i++)   
112.   
113.           {   
114.              int x = (int)(Math.random() * WIDTH);   
115.   
116.              int y = (int)(Math.random() * HEIGHT);   
117.   
118.              int red = (int)(Math.random() * 255);   
119.   
120.              int green = (int)(Math.random() * 255);   
121.   
122.              int blue = (int)(Math.random() * 255);   
123.   
124.              g.setColor(new Color(red,green,blue));           
125.   
126.              g.drawOval(x,y,1,0);   
127.   
128.           }   
129.              
130.           //加兩條干擾線   
131.           g.drawLine(0, 5, 90, 5);   
132.           g.drawLine(0, 15, 90, 15);   
133.   
134.        }   
135.   
136.        public static void main(String args[]) {   
137.            char[] chars = generateCheckCode();   
138.   
139.            System.out.println(chars);   
140.        }   
141. }  

package com.stone.study.validate;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class ImgValidateServlet2 extends HttpServlet {
private static int WIDTH = 90;
private static int HEIGHT = 20;
private static int LENGTH = 6;
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
response.setContentType("image/jpeg");
ServletOutputStream sos = response.getOutputStream();
//設(shè)置瀏覽器不要緩存此圖片
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
//創(chuàng)建內(nèi)存圖象并獲得其圖形上下文
BufferedImage image =
new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
//產(chǎn)生隨機(jī)的認(rèn)證碼
char [] rands = generateCheckCode();
//產(chǎn)生圖像
drawBackground(g);
drawRands(g,rands);
//結(jié)束圖像的繪制過程,，完成圖像
g.dispose();
//將圖像輸出到客戶端
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(image, "JPEG", bos);
byte [] buf = bos.toByteArray();
response.setContentLength(buf.length);
//下面的語句也可寫成：bos.writeTo(sos);
sos.write(buf);
bos.close();
sos.close();
//將當(dāng)前驗證碼存入到Session或者數(shù)據(jù)庫中,下一個表單處理中驗證客戶端提交的驗證碼是否正確
session.setAttribute("check_code",new String(rands));
}
private static char [] generateCheckCode()
{
//定義驗證碼的字符表
String chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char [] rands = new char[LENGTH];
for(int i=0; i<LENGTH; i++)
{
int rand = (int)(Math.random() * 36);
rands[i] = chars.charAt(rand);
}
return rands;
}
private void drawRands(Graphics g , char [] rands)
{
g.setColor(Color.BLACK);
g.setFont(new Font(null,Font.ITALIC|Font.BOLD,18));
//在不同的高度上輸出驗證碼的每個字符
g.drawString("" + rands[0],1,17);
g.drawString("" + rands[1],16,15);
g.drawString("" + rands[2],31,18);
g.drawString("" + rands[3],46,16);
g.drawString("" + rands[4],61,14);
g.drawString("" + rands[5],76,19);
System.out.println(rands);
}
private void drawBackground(Graphics g)
{
//畫背景
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, WIDTH, HEIGHT);
//隨機(jī)產(chǎn)生120個干擾點
for(int i=0; i<120; i++)
{
int x = (int)(Math.random() * WIDTH);
int y = (int)(Math.random() * HEIGHT);
int red = (int)(Math.random() * 255);
int green = (int)(Math.random() * 255);
int blue = (int)(Math.random() * 255);
g.setColor(new Color(red,green,blue));
g.drawOval(x,y,1,0);
}
//加兩條干擾線
g.drawLine(0, 5, 90, 5);
g.drawLine(0, 15, 90, 15);
}
public static void main(String args[]) {
char[] chars = generateCheckCode();
System.out.println(chars);
}
}