java 验证码组件

JAVA验证码组件,经常在浏览网页登陆或者其他什么的时候,通常会有一个验证码的东西。现在的项目刚好也用到,找了下资料,总结如下:

写一个servlet类 getimg.java:

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.util.*;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.*;
import javax.servlet.http.*;

import org.apache.commons.lang.RandomStringUtils;

public class getimg extends HttpServlet {

 /**
  *
  */
 private static final long serialVersionUID = 1L;

 /**
  * Constructor of the object.
  */
 public getimg() {
  super();
 }

 /**
  * Destruction of the servlet. <br>
  */
 public void destroy() {
  super.destroy(); // Just puts "destroy" string in log
  // Put your code here
 }

 /**
  * The doGet method of the servlet. <br>
  *
  * This method is called when a form has its tag value method equals to get.
  *
  * @param request the request send by the client to the server
  * @param response the response send by the server to the client
  * @throws ServletException if an error occurred
  * @throws IOException if an error occurred
  */
 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  response.setHeader("Pragma","No-cache");
  response.setHeader("Cache-Control","no-cache");
  response.setDateHeader("Expires", 0);
//      定义图片长度和宽度  
  int width=176, height=30;
//  创建内存图像
  BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
  Graphics g = image.getGraphics();
  Random random = new Random();  
//   验证码图形显示为数字和英文字母
  g.setColor(getRandColor(200,250));
  g.fillRect(0, 0, width, height);
  g.setFont(new Font("Times New Roman",Font.BOLD,18));
  g.setColor(new Color(255,255,255));
  g.drawRect(0,0,width-1,height-1);
  g.setColor(getRandColor(160,200));
  for (int i=0;i<155;i++)
  {
  
          int x = random.nextInt(width);
          int y = random.nextInt(height);
          int xl = random.nextInt(12);
          int yl = random.nextInt(12);
          g.drawLine(x,y,x+xl,y+yl);
  }
//      随机获取四位字母或数字型字符    
  String s = RandomStringUtils.random(4,false,true); 

  g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
//  将字符画到图片上
  g.drawString(s,6,20);
 
/* 显示汉字验证码 
//       设置备选汉字,剔除一些不雅的汉字
    String base = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
//       备选汉字的长度
    int length = base.length(); 
//   设定图像背景色(因为是做背景,所以偏淡)
    g.setColor(getRandColor(200, 250));
    g.fillRect(0, 0, width, height);
//       备选字体
    String[] fontTypes = {"\u5b8b\u4f53", "\u65b0\u5b8b\u4f53", "\u9ed1\u4f53", "\u6977\u4f53", "\u96b6\u4e66"};
    int fontTypesLength = fontTypes.length;
//   在图片背景上增加噪点
    g.setColor(getRandColor(160, 200));
    g.setFont(new Font("Times New Roman", Font.PLAIN, 14));
    for (int i = 0; i < 6; i++) {
      g.drawString("*********************************************", 0, 5 * (i + 2));
    }

  String s = "";
  for (int i = 0; i < 6; i++) {
      int start = random.nextInt(length);
      String rand = base.substring(start, start + 1);
      s += rand;
    //设置字体的颜色
      g.setColor(getRandColor(10, 150));
    //设置字体
      g.setFont(new Font(fontTypes[random.nextInt(fontTypesLength)], Font.BOLD, 18 + random.nextInt(6)));
    //将此汉字画到图片上
      g.drawString(rand, 24 * i + 10 + random.nextInt(8), 24);
    }
   
*/   
  HttpSession session=request.getSession();
  session.setAttribute("rand",s);
  g.dispose();
  ImageIO.write(image, "JPEG", response.getOutputStream());
 }
 Color getRandColor(int fc,int bc){
  Random random = new Random();
        if(fc>255) fc=255;
        if(bc>255) bc=255;
        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);
        }
 /**
  * The doPost method of the servlet. <br>
  *
  * This method is called when a form has its tag value method equals to post.
  *
  * @param request the request send by the client to the server
  * @param response the response send by the server to the client
  * @throws ServletException if an error occurred
  * @throws IOException if an error occurred
  */
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
  out
    .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
  out.println("<HTML>");
  out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
  out.println("  <BODY>");
  out.print("    This is ");
  out.print(this.getClass());
  out.println(", using the POST method");
  out.println("  </BODY>");
  out.println("</HTML>");
  out.flush();
  out.close();
 }

 /**
  * Initialization of the servlet. <br>
  *
  * @throws ServletException if an error occure
  */
 public void init() throws ServletException {
  // Put your code here
 }

}

到此,servlet 写完了,怎么调用呢?

1、新建一个Web工程
 2、在工程的src下新建一个包SMART.JRSOFT.IDENTTIFYINGCODE
 3、新建一个servlet类getimg.java,将Source下的getimg.java拷贝到新建的包com.yihaomen里面
      
       servlet配置文件如下:
       <servlet>
           <description>This is the description of my J2EE component</description>
           <display-name>This is the display name of my J2EE component</display-name>
           <servlet-name>getimg</servlet-name>
           <servlet-class>com.yihaomen.getimg</servlet-class>
       </servlet>
       <servlet-mapping>
           <servlet-name>getimg</servlet-name>
           <url-pattern>/servlet/getimg</url-pattern>
       </servlet-mapping>

 4、将Jsp下的页面拷贝到工程的WebRoot下面
 5、运行工程显示页面GetImage.jsp就可以显示验证码信息
        6、如果要显示汉字验证码信息,需要把getimg.java中注释掉的汉字验证码部分释放出来,同时将数字和字符验证码部分注释。
运行注意事项:
 1、注意包名的大小写情况
 2、注意页面的编码问题

测试的JSP页面如下。

<%@ page contentType="text/html; charset=utf-8"%>
<%
 String path=request.getContextPath();
%>
<html>
  <table>
 <tr>
   <td width="20%" align="right">验 证 码:</td>
   <td width="40%" align="left"><input type="text" name="validateNO" size="20" /><font color="red">*</font>
 <!-- 验证码的显示 -->
     <img src="<%=path%>/servlet/getimg" width="77" height="20" />
 <!-- 验证码的显示 -->
   </td>
   <td width="40%" align="left" class="showtxt">请输入验证码</td>
 </tr>
 <tr>
       <td align="center" colspan="3" height="35">
        <input type="submit" value="提 交">
       </td>
    </tr>
  </table>
</html>

这样就可以了,可以测试下。



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