1---jsp
<body>
<img src="YanZhangma" >
</body>
2----servlet
package com.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
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 YanZhangma extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
//定义一个随机数的数组
String[] str={"1","2","h","w","y","8","t","0","a","g"};
//定义宽和高
int height=50,width=100;
//得到画布
BufferedImage image=new BufferedImage (width,height, BufferedImage.TYPE_3BYTE_BGR);
//创建画笔
Graphics g=image.getGraphics();
//设置矩形背景色
g.setColor(Color.yellow);
//制作矩形背景
g.fillRect(0, 0,width, height);
//设置边框颜色
g.setColor(Color.red);
//设置边框
g.drawRect(0, 0, width-1, height-1);
//产生随机数
String str1="";
Random rand=new Random();
for(int i=0;i<4;i++){
//产生1-10 得到数组的下标
int num=rand.nextInt(10);
str1+=str[num];
}
//设置字体
g.setFont(new Font("宋体",Font.BOLD,30));
g.drawString(str1, 20, 20);
//设置颜色
g.setColor(Color.green);
//写入画布
//写一些点干扰
//设置颜色
g.setColor(Color.black);
for(int i=0;i<15;i++){
g.fillOval(rand.nextInt(60), rand.nextInt(20), 2, 2);
}
//创建输入流对象
OutputStream out=resp.getOutputStream();
//创建图片IO流
ImageIO.write(image, "jpg", out);
}
}