生成图片验证码

页面

js

    //获取验证码
    function changeValidateCode() {
	    var timenow = new Date().getTime();
	    $("#img").attr('src', '/verifyCode?d=' + timenow);//页面img标签的src属性 
	    //verifyCode 后台方法 加时间戳防止缓存
    }

java

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.util.Random;
import java.util.UUID;

import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/")
public class VerifyCodeController {
	private static final long serialVersionUID = 1L;
	private ByteArrayInputStream inputStream;

	@RequestMapping("verifyCode")
	public void execute(HttpServletRequest request, HttpServletResponse response) throws Exception {
		int width = 60;
		int height = 28;
		BufferedImage image = new BufferedImage(width, height, 1);

		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, 18));

		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);
		}

		UUID uId = UUID.randomUUID();
		String sRand = uId.toString().substring(0, 5);

		g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));

		g.drawString(sRand, 4, 22);

		// contrller 获取session
		request.getSession().setAttribute("verifyCode", sRand);

		g.dispose();
		// 把图片写到输出流中
		// 字节数组输出流在内存中创建一个字节数组缓冲区，所有发送到输出流的数据保存在该字节数组缓冲区中
		ServletOutputStream out = response.getOutputStream();
		// 返回一个 ImageOutputStream，它将其输出发送到给定 Object
		ImageOutputStream imageOut = ImageIO.createImageOutputStream(out);
		ImageIO.write(image, "JPEG", imageOut);
		imageOut.close();
	}

	private 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);
	}

	public void setInputStream(ByteArrayInputStream inputStream) {
		this.inputStream = inputStream;
	}

	public ByteArrayInputStream getInputStream() {
		return this.inputStream;
	}
}