JavaWeb实现成语图片验证码

结构图以下：

Java的action层下建立一个Servlet，名字：checkImg_Servlet 

package com.liaoyuanping.action; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.List; import java.util.Random; import javax.imageio.ImageIO; //import java.io.IOException;
import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/checkImg_Servlet") public class checkImg_Servlet extends HttpServlet { private List<String> words = new ArrayList<String>(); public void init(ServletConfig config) throws ServletException { words.add("廖远平帅"); words.add("廖远平酷"); words.add("廖远平棒"); words.add("人才辈出"); words.add("危在旦夕"); 　　　　　//因为试过多个读取文件的方式都出现错误，暂时使用手动加进数组，
　　　　 //之后是使用配置文件进行操做的
　　　　 /* * //初始化阶段，读取new_words.txt文件 //Web工程读取文件，必须使用绝对磁盘路径 * System.out.println("初始化1"); * * System.out.println("contextPath："+this.getServletContext()); * * try { InputStreamReader reader22 = new InputStreamReader(new * FileInputStream("..."),"UTF-8"); } catch * (UnsupportedEncodingException e1) { // TODO Auto-generated catch * block e1.printStackTrace(); } catch (FileNotFoundException e1) { // * TODO Auto-generated catch block e1.printStackTrace(); } * //System.out.println("contextPath："+this.getServletContext(). * getContextPath()); //InputStreamReader reader = new * InputStreamReader(new FileInputStream(realPath),"UTF-8"); * * String path = getServletContext().getRealPath(""); * System.out.println("初始化2"); System.out.println(path); path += * "new_words.txt"; * * * * try { BufferedReader reader = new BufferedReader( null ); * //BufferedReader reader = new BufferedReader(new FileReader(path)); * String line; while((line = reader.readLine()) != null){ * words.add(line); } reader.close(); } catch (IOException e) { * System.out.println("初始化发生异常："+e.getMessage()); e.printStackTrace(); } * System.out.println("初始化关键字。。。。完成"); */ } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 禁止缓存
        int width = 120; int height = 30; System.out.println("开始执行"); // 步骤一：绘制一张内存中的图片
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 步骤二：图片绘制背景颜色 --经过绘图对象
        Graphics graphics = bufferedImage.getGraphics(); // 获得画图对象，画笔 // 绘制任何图形以前都必须指定一个颜色
        graphics.setColor(getRandColor(200, 250)); graphics.fillRect(0, 0, width, height); // 绘制边框
 graphics.setColor(Color.WHITE); graphics.drawRect(0, 0, width - 1, height - 1); // 步骤四：设置四个随机数字
        Graphics2D graphics2d = (Graphics2D) graphics; // 设置输出的字体
        graphics2d.setFont(new Font("宋体", Font.BOLD, 18)); Random random = new Random(); // 生成随机数
        int index = random.nextInt(words.size()); String word = words.get(index); // 得到成语 // 定义x的坐标
        int x = 10; for (int i = 0; i < word.length(); i++) { // 随机颜色
            graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110))); // 旋转 -30度--正30度
            int jiaodu = random.nextInt(60) - 30; // 换算弧度
            double theta = jiaodu * Math.PI / 180; // 得到字母数字
            char c = word.charAt(i); // 将 c 输出到图片
            graphics2d.rotate(theta, x, 20); graphics2d.drawString(String.valueOf(c), x, 20); graphics2d.rotate(-theta, x, 20); x += 30; } // 将验证码内容保存到session
        request.getSession().setAttribute("checkcode_session", word); // 步骤五：绘制干扰线
        graphics.setColor(getRandColor(160, 200)); int x1; int x2; int y1; int y2; for (int i = 0; i < 30; i++) { x1 = random.nextInt(width); x2 = random.nextInt(12); y1 = random.nextInt(height); y2 = random.nextInt(12); graphics.drawLine(x1, y1, x1 + x2, x2 + y2); } // 将上面的图片加载到浏览器ImageIo
        graphics.dispose(); // 释放资源 // 将图片写到response.getOutputStream()中
        ImageIO.write(bufferedImage, "jpg", response.getOutputStream()); } /* * 取其某一范围的color * * @param fc int 范围参数1 * * @param bc int 范围参数2 * * @return Color */
    private Color getRandColor(int fc, int bc) { // 取其随机颜色
        Random random = new Random(); if (fc > 255) { fc = 255; // 限定最大值
 } if (bc > 255) { bc = 255; // 也是限定最大值
 } int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }

HTML代码以下：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
<script type="text/javascript"> window.onload = function(){ } function changeImg (obj){ obj.src ="checkImg?time="+new Date().getTime(); //设置有效期
        //document.getElementById("validateCodeImg").src="${pageContext.request.contextPath}/servlet/DrawImage?"+Math.random();
 } </script>
</head>

<body>
    <form action="/WEB13/login" method="post"> 用户名：<input type="text" name="username"><br> 密码：<input type="password" name="password"><br> 验证码：<input type="text" name="username"><img onclick="changeImg(this)" src="checkImg_Servlet"><br/>
        <input type="button" name="btnLogin" value="登陆"><br/>
    </form>
</body>
</html>

 不过这个案例还有一些问题，也正在解决当中，还请各位大佬指点