springboot中驗證碼功能

1、寫一個驗證碼生成類（網上有，可以從網上直接拿）

package com.chinaunicom.ems.utils;


import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Random;

import javax.imageio.ImageIO;

public class VerifyCodeUtils {

    /**
     * 驗證碼難度級別 Simple-數字 Medium-數字和小寫字母 Hard-數字和大小寫字母
     */
    public enum SecurityCodeLevel {
        Simple, Medium, Hard
    };

    /**
     * 產生默認驗證碼，4位中等難度
     *
     * @return
     */
    public static String getSecurityCode() {
        return getSecurityCode(4, SecurityCodeLevel.Medium, false);
    }

    /**
     * 產生長度和難度任意的驗證碼
     *
     * @param length
     * @param level
     * @param isCanRepeat
     * @return
     */
    public static String getSecurityCode(int length, SecurityCodeLevel level, boolean isCanRepeat) {
        // 隨機抽取len個字符
        int len = length;
        // 字符集合（--除去易混淆的數字0,1,字母l,o,O）
        char[] codes = {
                '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
                'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
        };
        // 根據不同難度截取字符串
        if (level == SecurityCodeLevel.Simple) {
            codes = Arrays.copyOfRange(codes, 0, 10);
        } else if (level == SecurityCodeLevel.Medium) {
            codes = Arrays.copyOfRange(codes, 0, 36);
        }
        // 字符集和長度
        int n = codes.length;
        // 拋出運行時異常
        if (len > n && isCanRepeat == false) {
            throw new RuntimeException(String.format("調用SecurityCode.getSecurityCode(%1$s,%2$s,%3$s)出現異常，" + "當isCanRepeat為%3$s時，傳入參數%1$s不能大於%4$s", len, level, isCanRepeat, n));
        }
        // 存放抽取出來的字符
        char[] result = new char[len];
        // 判斷能否出現重復字符
        if (isCanRepeat) {
            for (int i = 0; i < result.length; i++) {
                // 索引0 and n-1
                int r = (int) (Math.random() * n);
                // 將result中的第i個元素設置為code[r]存放的數值
                result[i] = codes[r];
            }
        } else {
            for (int i = 0; i < result.length; i++) {
                // 索引0 and n-1
                int r = (int) (Math.random() * n);
                // 將result中的第i個元素設置為code[r]存放的數值
                result[i] = codes[r];
                // 必須確保不會再次抽取到那個字符，這里用數組中最后一個字符改寫code[r],並將n-1
                codes[r] = codes[n - 1];
                n--;
            }
        }
        return String.valueOf(result);
    }

    /**
     * 生成驗證碼圖片
     * @param securityCode
     * @return
     */
    public static BufferedImage createImage(String securityCode){

        int codeLength = securityCode.length();//驗證碼長度

        int fontSize = 18;//字體大小

        int fontWidth = fontSize+1;

        //圖片寬高

        int width = codeLength*fontWidth+6;
        int height = fontSize*2+1;
        //圖片

        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        Graphics2D g = image.createGraphics();

        g.setColor(Color.WHITE);//設置背景色

        g.fillRect(0, 0, width, height);//填充背景

        g.setColor(Color.LIGHT_GRAY);//設置邊框顏色

        g.setFont(new Font("Arial", Font.BOLD, height-2));//邊框字體樣式

        g.drawRect(0, 0, width-1, height-1);//繪制邊框

        //繪制噪點

        Random rand = new Random();

        g.setColor(Color.LIGHT_GRAY);

        for (int i = 0; i < codeLength*6; i++) {

            int x = rand.nextInt(width);

            int y = rand.nextInt(height);

            g.drawRect(x, y, 1, 1);//繪制1*1大小的矩形

        }

        //繪制驗證碼

        int codeY = height-10;

        g.setColor(new Color(19,148,246));

        //Georgia  是個字體，如果想用中文要指定中文字體；eg:"宋體";
        //g.setFont(new Font("Georgia", Font.BOLD, fontSize));
        g.setFont(new Font("宋體", Font.BOLD, fontSize));
        for(int i=0;i<codeLength;i++){
            double deg=new Random().nextDouble()*20;
            g.rotate(Math.toRadians(deg), i*16+13,codeY-7.5);
            g.drawString(String.valueOf(securityCode.charAt(i)), i*16+5, codeY);
            g.rotate(Math.toRadians(-deg), i*16+13,codeY-7.5);
        }

        g.dispose();//關閉資源

        return image;

    }

    //測試
    public static void main(String[] args) throws IOException{
        //獲得隨機字符
        String securityCode = getSecurityCode();
        //輸出隨機字符
        System.out.println("===="+securityCode);
        //生成圖片
        BufferedImage image = createImage(securityCode);
        //將生成的驗證碼圖片以png(1.png)的格式輸出到D盤        "D:\\1.png" == "D:/1.png"
        ImageIO.write(image, "png", new FileOutputStream(new File("D:\\1.png")));
    }


}

第二、在控制層寫

package com.chinaunicom.ems.controller;

import com.chinaunicom.ems.utils.VerifyCodeUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.image.BufferedImage;
import java.io.IOException;

@Controller
@RequestMapping("user")
public class UserController{


    //生成驗證碼
    @GetMapping("getImage")
    public void getImage(HttpSession session, HttpServletResponse response) throws IOException {
        //生成驗證碼
        String securityCode = VerifyCodeUtils.getSecurityCode();
        //將驗證碼放入session
        session.setAttribute("code",securityCode);
        //生成圖片
        BufferedImage image = VerifyCodeUtils.createImage(securityCode);
        //輸出圖片
        ServletOutputStream outputStream = response.getOutputStream();

        //調用工具類
        ImageIO.write(image,"png",outputStream);
    }
}

想用HttpServletRequest和HttpServletResponse等對象就要引入依賴：

<dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>

然后jsp文件以及jsp的熱部署

<%@ page language="java" pageEncoding="utf-8" isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <title>regist</title>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <link rel="stylesheet" type="text/css" href="css/style.css" />
    </head>
    <body>
        <div id="wrap">
            <div id="top_content">
                    <div id="header">
                        <div id="rightheader">
                            <p>
                                2009/11/20
                                <br />
                            </p>
                        </div>
                        <div id="topheader">
                            <h1 id="title">
                                <a href="#">main</a>
                            </h1>
                        </div>
                        <div id="navigation">
                        </div>
                    </div>
                <div id="content">
                    <p id="whereami">
                    </p>
                    <h1>
                        注冊
                    </h1>
                    <form action="login.html" method="post">
                        <table cellpadding="0" cellspacing="0" border="0"
                            class="form_table">
                            <tr>
                                <td valign="middle" align="right">
                                    用戶名:
                                </td>
                                <td valign="middle" align="left">
                                    <input type="text" class="inputgri" name="username" />
                                </td>
                            </tr>
                            <tr>
                                <td valign="middle" align="right">
                                    真實姓名:
                                </td>
                                <td valign="middle" align="left">
                                    <input type="text" class="inputgri" name="name" />
                                </td>
                            </tr>
                            <tr>
                                <td valign="middle" align="right">
                                    密碼:
                                </td>
                                <td valign="middle" align="left">
                                    <input type="password" class="inputgri" name="pwd" />
                                </td>
                            </tr>
                            <tr>
                                <td valign="middle" align="right">
                                    性別:
                                </td>
                                <td valign="middle" align="left">
                                    男
                                    <input type="radio" class="inputgri" name="sex" value="m" checked="checked"/>
                                    女
                                    <input type="radio" class="inputgri" name="sex" value="f"/>
                                </td>
                            </tr>
                            
                            <tr>
                                <td valign="middle" align="right">
                                    驗證碼:
                                    <img id="num" src="${pageContext.request.contextPath}/user/getImage" />
                                    <a href="javascript:;" onclick="document.getElementById('num').src = '${pageContext.request.contextPath}/user/getImage?'+(new Date()).getTime()">換一張</a>
                                </td>
                                <td valign="middle" align="left">
                                    <input type="text" class="inputgri" name="number" />
                                </td>
                            </tr>
                        </table>
                        <p>
                            <input type="submit" class="button" value="Submit &raquo;" />
                        </p>
                    </form>
                </div>
            </div>
            <div id="footer">
                <div id="footer_bg">
                [e-mail]
                </div>
            </div>
        </div>
    </body>
</html>

圖中標紅的是獲取圖片的路徑的。

server:
    jsp:
      init-parameters:
        development: true

//jsp熱部署的配置

 注意點：要保證實體類與jsp文件里面的名稱命名時一致的

代碼結構：