简单实现Java验证码功能

2019-11-26 12:22:54

字体：大中小

来源：转载

供稿：网友

今晚看到网上有关验证码的实现的代码，很早就想写一个了，感觉验证码挺有意思的，于是就写了一个，然而后来一直加载不出图片。尝试了很多方法，后来终于解决了，原来是我项目里面的 web.xml中没有部署servlet的映射，web.xml如下图：

运行效果如下：

代码如下：

package model;  import javax.imageio.ImageIO; import java.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.OutputStream; import java.util.Random;  /**  * Created by Petty on 2017/5/4.  */ public class VCode {   private int w; //图片宽  private int h;//图片高  private Color bgColor = new Color(240,240,240);//背景色  private Random random = new Random();//随机对象  //设置字体范围  private String[] fontNames = {"宋体","华文楷体","黑体","华文新魏","华文隶书","微软雅黑","楷体"};  //设置字体样式范围  private int[] fontstyle = {0,1,2,3};  //设置字号范围  private int[] fontSizes = {24,25,26,27,28};  //设置所有字符串范围  private String codes="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";    //无参数构造函数  public VCode(){   }   //带宽和高的构造函数  public VCode(int w,int h){   this.w = w;   this.h = h;  }   //返回一张背景图片  private BufferedImage createImage(){   /**    * 1.创建图片 2.设置背景色    */   //创建图片   BufferedImage img = new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);   //设置背景色   Graphics g = img.getGraphics();   g.setColor(bgColor);   g.fillRect(0,0,w,h);   return img;  }    // 随机返回字体颜色  private Color randomColor() {      int r = random.nextInt(256);      int g = random.nextInt(256);      int b = random.nextInt(256);    return new Color(r, g, b);    }    //随机返回字体样式  private Font randomFont(){   //随机生成字体下标，随机从给定的范围内获取一个字体   int index = random.nextInt(fontNames.length);   String name = fontNames[index];    //随机生成字体样式下标，随即从给定的范围内获取一个字体样式   index = random.nextInt(fontstyle.length);   int style = fontstyle[index];    //随机生成字体大小下标，随机从给定的范围内获取一个字体大小   index = random.nextInt(fontSizes.length);   int size = fontSizes[index];    return new Font(name,style,size);  }    //随机返回字体内容  private String randomChar(){   int index = random.nextInt(codes.length());    return codes.charAt(index)+"";  }    //随机返回几条干扰线  private void getLine(BufferedImage img){   //设置干扰线的宽度为1.5倍宽，随机画五条   Graphics2D g =(Graphics2D) img.getGraphics();   g.setColor(Color.BLACK);   g.setStroke(new BasicStroke(1.5f));   for(int i=0;i<5;i++){    int x1 = random.nextInt(w);    int y1 = random.nextInt(h);    int x2 = random.nextInt(w);    int y2 = random.nextInt(h);    g.drawLine(x1,y1,x2,y2);   }  }    //用户调用该方法获取图片  public BufferedImage getImage(){   /**    * 随机生成字符0-9A-Za-z,设置字体，字号，是否粗体，字符颜色，都是随机的    */   BufferedImage img = createImage();    this.getLine(img);    //获取画笔   Graphics g = img.getGraphics();    //画内容   for(int i=0;i<4;i++){    g.setColor(this.randomColor());//获取随机颜色    g.setFont(this.randomFont());//获取随机字体    g.drawString(this.randomChar(),w/4*i,h-5);//获取字符串随机内容   }   return img;  }    //用户调用该方法保存图片到本地  public void saveImage(BufferedImage img, OutputStream ous){    try {    ImageIO.write(img,"JPEG",ous);   } catch (IOException e) {    e.printStackTrace();   }  } }

package model;  import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.awt.image.BufferedImage; import java.io.IOException;  /**  * Created by Petty on 2017/5/4.  */ @WebServlet(name = "BServlet") public class BServlet extends HttpServlet {  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   VCode v = new VCode(70,35);   BufferedImage img = v.getImage();   v.saveImage(img,response.getOutputStream());  }   public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   VCode v = new VCode(70,35 );   BufferedImage img = v.getImage();   v.saveImage(img,response.getOutputStream());  } }

<%--  Created by IntelliJ IDEA.  User: Petty  Date: 2017/5/4  Time: 22:28  To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html>  <head>  <title>一次性验证码</title>  </head>  <body>  <form action="" method="get">   <table align="center">    <tr>     <td><img id="img" alt="" src="servlet/BServlet" onclick="changeNext()"></td>    </tr>   </table>  </form>  </body> </html> <script type="text/javascript">  function changeNext(){   var a=document.getElementById("img");   a.src="servlet/BServlet?a="+new Date().getTime();  } </script>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。

上一篇：SpringMVC结合天气api实现天气查询

下一篇：浅谈使用setBounds()方法需要注意的地方