servlet实现随即生成验证码图片

package generate.image;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;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.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class GenImage extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {BufferedImage image=new BufferedImage(120, 25, BufferedImage.TYPE_INT_RGB);//在内存中生成图片Graphics2D g=(Graphics2D) image.getGraphics();setBackGround(g);setBorder(g);drawRandomLine(g);drawRandomNum(g);response.setContentType("image/jpeg");//设置内容格式ImageIO.write(image, "jpg", response.getOutputStream());//将图片输出}private void drawRandomNum(Graphics2D g) {g.setColor(Color.RED);Font font=new Font("宋体",Font.BOLD,100);//设置字体String str="abcdefghi1234567890jklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";int x=20;for(int i=0;i<5;i++){int degree = new Random().nextInt()%30;//使字体旋转-30到30度char  ch=str.charAt(new Random().nextInt(57));//随机选取字符g.rotate(degree*Math.PI/180, x, 20);g.drawString(ch+"", x, 20);g.rotate(-degree*Math.PI/180, x, 20);x+=20;}}//根据随机产生的坐标画随机线private void drawRandomLine(Graphics g) {g.setColor(Color.BLUE);for(int i=0;i<5;i++){int x1=new Random().nextInt(120);int y1=new Random().nextInt(25);int x2=new Random().nextInt(120);int y2=new Random().nextInt(25);g.drawLine(x1, y1, x2, y2);}}//设置边框颜色及范围private void setBorder(Graphics g) {g.setColor(Color.GREEN);g.drawRect(0, 0, 119, 24);}//设置背景颜色private void setBackGround(Graphics g) {g.setColor(Color.WHITE);g.fillRect(0, 0, 120, 25);}}