图片验证码

package com.test.yzm;


import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
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 yzm extends HttpServlet {


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


public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//指定图片的大小
int width = 120;
int height = 30;
//创建一个图片
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//拿到图片的画笔
Graphics g = image.getGraphics();
//指定边框的颜色
g.setColor(Color.BLACK);
//先画出图片的边框
g.drawRect(0, 0, width, height);
//填充颜色
g.setColor(Color.WHITE);
g.fillRect(1, 1, width-2, height-2);
//画出30条干扰线
g.setColor(Color.GRAY);
Random random = new Random();
for (int i = 0; i < 50; i++) {
g.drawLine(random.nextInt(width), random.nextInt(height), random.nextInt(width), random.nextInt(height));
}
//填充内容
g.setColor(Color.BLUE);
g.setFont(new Font("幼圆", Font.BOLD+Font.ITALIC, 15));
//填充数字
for (int i = 0; i < 6; i++) {
g.drawString(random.nextInt(10)+"", 15+15*i+random.nextInt(5), 18+random.nextInt(5));
}
//通知浏览器不要缓存
response.setHeader("Expires", -1+"");
response.setHeader("Cache-Control", "no-Cache");
response.setHeader("Pragam", "no-Cache");
//将图片输送到页面上
ImageIO.write(image, "jpg", response.getOutputStream());
}
}