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：
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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(); } } } |
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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()); } } |
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<%-- 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> |
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