如何用Servlet-SpringMVC生成验证码？
摘要：在SpringMVC中配置生成验证码：
在SpringMVC中配置生成验证码：
1 import org.springframework.stereotype.Controller;
2 import org.springframework.web.bind.annotation.RequestMapping;
3
4
5 import java.awt.Color;
6 import java.awt.Graphics;
7 import java.awt.image.BufferedImage;
8 import java.io.IOException;
9 import java.io.PrintWriter;
10 import java.util.Random;
11
12 import javax.imageio.ImageIO;
13 import javax.servlet.ServletException;
14 import javax.servlet.http.HttpServletRequest;
15 import javax.servlet.http.HttpServletResponse;
16
17 @Controller
18 public class RegisterController {
19
20
21 // 图片高度
22 private static final int IMG_HEIGHT = 100;
23 // 图片宽度
24 private static final int IMG_WIDTH = 30;
25 // 验证码长度
26 private static final int CODE_LEN = 4;
27
28 @RequestMapping(value = "/getCode.action")
29 public void getCode(HttpServletRequest req, HttpServletResponse resp)
30 throws ServletException, IOException {
31 // 用于绘制图片，设置图片的长宽和图片类型（RGB)
32 BufferedImage bi = new BufferedImage(IMG_HEIGHT, IMG_WIDTH, BufferedImage.TYPE_INT_RGB);
33 // 获取绘图工具
34 Graphics graphics = bi.getGraphics();
35 graphics.setColor(new Color(100, 230, 200)); // 使用RGB设置背景颜色
36 graphics.fillRect(0, 0, 100, 30); // 填充矩形区域
37
38 // 验证码中所使用到的字符
39 char[] codeChar = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456".toCharArray();
40 String captcha = ""; // 存放生成的验证码
41 Random random = new Random();
42 for(int i = 0; i < CODE_LEN; i++) { // 循环将每个验证码字符绘制到图片上
43 int index = random.nextInt(codeChar.length);
44 // 随机生成验证码颜色
45 graphics.setColor(new Color(random.nextInt(150), random.nextInt(200), random.nextInt(255)));
46 // 将一个字符绘制到图片上，并制定位置（设置x,y坐标）
47 graphics.drawString(codeChar[index] + "", (i * 20) + 15, 20);
48 captcha += codeChar[index];
49 }
50 // 将生成的验证码code放入sessoin中