response 画验证码

代码

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
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 ValiImage extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		int  width = 150;
		int  height = 50;
		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

		Graphics2D g = (Graphics2D) image.getGraphics();
		//添加背景颜色
		g.setColor(Color.GRAY);
		g.fillRect(0,0,width,height);
		//添加边框
		g.setColor(Color.black);
		g.drawRect(0,0,width-1,height-1);
		//画干扰线
		int count = 10;
		while(count>0)
		{
			g.setColor(Color.RED);
			g.drawLine(RandomNum(0,width), RandomNum(0,height),RandomNum(0,width), RandomNum(0,height));
			count--;
		}

		//画字体
		for(int p = 0 ; p < 4; p++)
		{
			g.setColor(new Color(RandomNum(0,255),RandomNum(0,255),RandomNum(0,255)));
			g.setFont(new Font("黑体",Font.BOLD,20));
			g.drawString("中",5+(p*37),25);
		}

		ImageIO.write(image,"jpg",response.getOutputStream());

	}
	private Random rand = new Random();
	public int RandomNum(int i,int j)
	{
		//返回一个大于i小于j的随机数
		//return rand.nextInt(j-i)+i;
		return i+(int)(Math.random()*j);
	}

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

}