Java生成随机图片验证码

前台html代码

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   <div style="margin-top: 50px;">
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   <span>验证码：</span><input type="text" name="verifyCode" id="verifyCode" style="width: 75px;height: 25px;"/>
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   <img id="verifyCodeImg" alt="点击更换" src="/qos/dog/getVerifyCodeImg"
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   title="点击更换" onclick="change()">
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   </div>

前台js代码

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   function change() {
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   var verifyCode = document.getElementById("verifyCodeImg");
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   verifyCode.src = "/qos/dog/getVerifyCodeImg?time=" + Math.random(1000);
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   }
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   /*-*/
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10. 
    /qos/dog/ 这里的路径是需要换成自己的哦
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验证代码，在controller里面新建一个util文件夹，然后放入VerifyCodeUtil.java
代码如下

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   package com.paladin.qos.util;
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   import javax.imageio.ImageIO;
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   import java.awt.*;
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   import java.awt.image.BufferedImage;
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   import java.io.ByteArrayOutputStream;
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   import java.io.IOException;
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   import java.util.Random;
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    public class VerifyCodeUtil {
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    private static final Random random = new Random();
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    private static final String[] fontNames = {"宋体", "华文楷体", "黑体", "Georgia", "微软雅黑", "楷体_GB2312"};
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    public static String drawImage(ByteArrayOutputStream output) {
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    String code = "";
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    int width = 50;
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    int height = 25;
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    //创建图片缓冲区
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    BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
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    Graphics2D g = bi.createGraphics();
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    //设置背景颜色
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    g.setBackground(new Color(255, 255, 255));
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    g.clearRect(0, 0, width, height);
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    StringBuilder stringBuilder = new StringBuilder();
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    //这里只画入四个字符
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    for (int i = 0; i < 4; i++) {
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    String s = randomChar() + ""; //随机生成字符，因为只有画字符串的方法，没有画字符的方法，所以需要将字符变成字符串再画
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    stringBuilder.append(s); //添加到StringBuilder里面
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    float x = i * 1.0F * width / 4; //定义字符的x坐标
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    g.setFont(randomFont()); //设置字体，随机
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    g.setColor(randomColor()); //设置颜色，随机
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    g.drawString(s, x, height - 5);
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    }
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    code = stringBuilder.toString(); //获取验证码字符串
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    //定义干扰线
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    //定义干扰线的数量（3-5条）int num = random.nextInt(max)%(max-min+1) + min;
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    int num = random.nextInt(5) % 3 + 3;
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    Graphics2D graphics = (Graphics2D) bi.getGraphics();
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    for (int i = 0; i < num; i++) {
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    int x1 = random.nextInt(width);
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    int y1 = random.nextInt(height);
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    int x2 = random.nextInt(width);
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    int y2 = random.nextInt(height);
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    graphics.setColor(randomColor());
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    graphics.drawLine(x1, y1, x2, y2);
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    }
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    // 释放图形上下文
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    g.dispose();
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    try {
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    ImageIO.write(bi, "jpg", output);
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    } catch (IOException e) {
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    e.printStackTrace();
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    }
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    return code; //为了方便取值，直接返回code，
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    }
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    //随机字体
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    private static Font randomFont() {
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    int index = random.nextInt(fontNames.length);
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    String fontName = fontNames[index];
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    int style = random.nextInt(4); //随机获取4种字体的样式
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    int size = random.nextInt(20) % 6 + 15; //随机获取字体的大小(10-20之间的值)
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    return new Font(fontName, style, size);
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    }
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    //随机颜色
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    private static Color randomColor() {
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    int r = random.nextInt(225);
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    int g = random.nextInt(225);
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    int b = random.nextInt(225);
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    return new Color(r, g, b);
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    }
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    //随机字符
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    private static char randomChar() {
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    //A-Z,a-z,0-9,可剔除一些难辨认的字母与数字
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    String str = "0123456789ABCdefghiDEFGHIJopPQRVWXYZabcjklSTUmnqrstKLMNOvuwxyz";
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    return str.charAt(random.nextInt(str.length()));
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    }
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    }

最后，在controller里面引用

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   @RequestMapping("/getVerifyCodeImg")
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   @ResponseBody
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   public void getVerifyCodeImg(HttpServletResponse response, HttpSession session) {
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   ByteArrayOutputStream output = new ByteArrayOutputStream();
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   String code = VerifyCodeUtil.drawImage(output);
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   //将验证码文本直接存放到session中
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   session.setAttribute("verifyCode", code);
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   try {
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   ServletOutputStream out = response.getOutputStream();
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    output.writeTo(out);
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    } catch (IOException e) {
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    e.printStackTrace();
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    }
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    }