使用response输出随机验证码图片。

Posted 2021-06-12 离落想AC

使用response输出随机验证码图片。

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
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;

/**
 * Servlet implementation class ResponsegetVerificationCode
 */
public class ResponsegetVerificationCode extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ResponsegetVerificationCode() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//response.getWriter().append("Served at: ").append(request.getContextPath());
	getVerificationCode(request,response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
	
	
	private void getVerificationCode(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException{
	
		response.setHeader("Expires", "-1");
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");
				
				int width = 120;
				int height = 25;
				BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
				Graphics g = image.getGraphics();
				g.setColor(Color.BLUE);
				g.drawRect(0, 0, width, height);
				g.setColor(Color.YELLOW);
				g.fillRect(1, 1, width-2, height-2);
				g.setColor(Color.GRAY);
				
				Random r = new Random();
				for(int i=0;i<10;i++)
					g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
				g.setColor(Color.RED);
				g.setFont(new Font("宋体", Font.BOLD|Font.ITALIC, 20));
				int x = 23;
				for(int i=0;i<4;i++){
					g.drawString(r.nextInt(10)+"", x, 20);
					x+=20;
				}
				ImageIO.write(image, "jpg", response.getOutputStream());
		
	}

}

浏览器访问： http://localhost:8888/MyJspProject/ResponsegetVerificationCode

Eclipse运行：