servlet awt随机图片验证码-优快云博客

本文介绍了一种使用Java生成带有中文字符的验证码图片的方法，并详细展示了如何通过Servlet将验证码发送到客户端，同时在服务器端进行验证码的有效性校验。

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package rd.test;

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;
//输出一张图片
public class Test1 extends HttpServlet {

	public static final int WIDTH = 120;
	public static final int HEIGHT = 35;
	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);

		Graphics g = image.getGraphics();
		
		//1,设置背景色
		setBackGround(g);
		
		//2，设置边框
		setBorder(g);
		
		//3，画干扰线
		drowRandomLine(g);
		
		//4，写随机数
		//drawRandomNum(g);
		String random = drawRandomNum2d((Graphics2D)g);//验证相关
　　　　　　　　　　request.getSession().setAttribute("checkcode",random);//验证相关		
		//5,图形写给浏览器
		response.setContentType("image/jpeg");
		//控制浏览器不要缓存随机验证码图片，让它每次都更新
		response.setDateHeader("expries", -1);
		response.setHeader("Cache-Control","no-cache");
		response.setHeader("Pragma","no-cache");
		ImageIO.write(image, "jpg", response.getOutputStream());
	}


	private void drowRandomLine(Graphics g) {
		// TODO Auto-generated method stub
		g.setColor(Color.GRAY);
		
		for(int i = 0;i<5;i++) {
			int x1 = new Random().nextInt(WIDTH-2)+2;
			int y1 = new Random().nextInt(HEIGHT-2)+2;
			
			int x2 = new Random().nextInt(WIDTH-2)+2;
			int y2 = new Random().nextInt(HEIGHT-2)+2;
			
			g.drawLine(x1, y1, x2, y2);
		}
	}

	private String drawRandomNum2d(Graphics2D g) {
		// TODO Auto-generated method stub
		g.setColor(Color.RED);
		g.setFont(new Font("宋体",Font.BOLD,20));
		//[\u4e00-\u9fa5]		
		String base = "一二三四五六七八九十百千万兆亿啊我饿依无余";

　　　　　　　　　　StringBuffer sb = new StringBuffer();//验证相关
		int x = 5;
		for(int i = 0;i<4;i++) {
			int degree = new Random().nextInt()%30;
			String ch = "" + base.charAt(new Random().nextInt(base.length()));
			sb.append(ch);//验证相关
　　　　　　　　　　　　　  g.rotate(degree*Math.PI/180, x, 25);//设置旋转幅度
			g.drawString(ch, x, 25);
			g.rotate(-degree*Math.PI/180, x, 25);//转回去
			x+=30;
		}

　　　　　　　　　　return sb.toString();
	}

	private void drawRandomNum(Graphics g) {
		g.setColor(Color.RED);
		g.setFont(new Font("宋体",Font.BOLD,20));
		//[\u4e00-\u9fa5]		
		String base = "一二三四五六七八九十百千万兆亿啊我饿依无余";

		int x = 5;
		for(int i = 0;i<4;i++) {
			String ch = "" + base.charAt(new Random().nextInt(base.length()));
			g.drawString(ch, x, 20);
			x+=30;
		}
		
	}

	private void setBorder(Graphics g) {
		g.setColor(Color.BLUE);
		g.drawRect(1, 1, WIDTH-2, HEIGHT-2);
		
	}


	private void setBackGround(Graphics g) {
		// TODO Auto-generated method stub
		g.setColor(Color.WHITE);
		g.fillRect(0, 0, WIDTH, HEIGHT);
	}


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


	}

}

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
    
    <script type="text/javascript">
        function changeImg(img){
            img.src = img.src + "?" + new Date().getTime();
        }
    </script>
    
  </head>
  
  <body>
  
      <form action="/web/servlet/check" method="post">
          用户名:<input type="text" name="username">
          密码 :<input type="password" name="password"><br/><br/>
          验证码:<input type = "text" name="checkcode">
          <img src="http://localhost:8080/random/servlet/Test1" onclick="changeImg(this)"/>
          <input type="submit" value="注册">
      </form> 
  </body>
</html>