import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * 驗證碼生成類
 * @author wangjiaxin
 *
 */
public class RandomValidateCode {

    public static final String RANDOMCODEKEY= "RANDOMVALIDATECODEKEY";//放到session中的key
    //private String randString = "0123456789";//隨機產生只有數字的字串 private String
    //private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//隨機產生只有字母的字串
    private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//隨機產生數字與字母組合的字串
    private int width = 100;// 圖片寬
    private int height = 40;// 圖片高
    private int lineSize = 60;// 干擾線數量
    private int stringNum = 4;// 隨機產生字元數量
    private int fontSize = 23;// 字元大小

    private Random random = new Random();

    /*
     * 獲得字型
     */
    private Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, fontSize);
    }

    /*
     * 獲得顏色
     */
    private Color getRandColor(int fc, int bc) {
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * 生成隨機圖片
     */
    public void getRandcode(HttpServletRequest request, HttpServletResponse response) {
        HttpSession session = request.getSession();
        // BufferedImage類是具有緩衝區的Image類,Image類是用於描述影象資訊的類
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();// 產生Image物件的Graphics物件,改物件可以在影象上進行各種繪製操作
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, fontSize));
        g.setColor(getRandColor(110, 133));
        // 繪製干擾線
        for (int i = 0; i <= lineSize; i++) {
            drowLine(g);
        }
        // 繪製隨機字元
        String randomString = "";
        for (int i = 1; i <= stringNum; i++) {
            randomString = drowString(g, randomString, i);
        }
        //將生成的隨機字串儲存到session中，而jsp介面通過session.getAttribute("RANDOMCODEKEY")，
        //獲得生成的驗證碼，然後跟使用者輸入的進行比較
        session.removeAttribute(RANDOMCODEKEY);
        session.setAttribute(RANDOMCODEKEY, randomString);
        g.dispose();
        try {
            // 將記憶體中的圖片通過流動形式輸出到客戶端
            ImageIO.write(image, "JPEG", response.getOutputStream());
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    /*
     * 繪製字串
     */
    private String drowString(Graphics g, String randomString, int i) {
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
                .nextInt(121)));
        String rand = String.valueOf(getRandomString(random.nextInt(randString
                .length())));
        randomString += rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        //調整字元位置，修改值即可（x不變，Y變即可）
        g.drawString(rand, 16 * i, 28);
        return randomString;
    }

    /*
     * 生成i位字串
     */
    public String getString(String randomStr,int i) {
        String randomNum = "";
        for (int j = 0; j < i; j++) {
            String rand = String.valueOf(getRandomString(random.nextInt(randomStr.length())));
            randomNum += rand;
        }
        return randomNum;
    }

    /*
     * 繪製干擾線
     */
    private void drowLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /*
     * 獲取隨機的字元
     */
    public String getRandomString(int num) {
        return String.valueOf(randString.charAt(num));
    }
}
 

校驗類

import com.www.util.RandomValidateCode;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.HashMap;
import java.util.Map;

/**
 * 驗證碼
 */
@Controller
@RequestMapping(value="codeKeyController")
public class CodeKeyController {

    /**
     * 登入頁面生成驗證碼
     */
    @RequestMapping(value = "getVerify")
    public void getVerify(HttpServletRequest request, HttpServletResponse response){
        response.setContentType("image/jpeg");//設定相應型別,告訴瀏覽器輸出的內容為圖片
        response.setHeader("Pragma", "No-cache");//設定響應頭資訊，告訴瀏覽器不要快取此內容
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expire", 0);
        RandomValidateCode randomValidateCode = new RandomValidateCode();
        try {
            randomValidateCode.getRandcode(request, response);//輸出驗證碼圖片方法
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 頁面校驗驗證碼（bootstrap驗證外掛）
     */
    @RequestMapping(value = "checkVerify")
    @ResponseBody
    public Map checkVerify(String inputStr, HttpSession session){
        Map<String, Boolean> map = new HashMap<String, Boolean>();
        //從session中獲取隨機數
        String random = (String) session.getAttribute("RANDOMVALIDATECODEKEY");
        if(random.equals(inputStr)){
            map.put("valid", true);//驗證碼正確
        }else{
            map.put("valid", false);//驗證碼錯誤
        }

        return map;
    }
}
 

html

<div class="verification" id="codeBtn">
                    <img id="imgVerify" src="" alt="點選更換驗證碼" class="codeBtn" width="100" height="40"
                         style="border: 1px solid #CCCCCC" onclick="getVerify(this);"/>
                </div>

js

$(document.body).ready(function () {
        //首次獲取驗證碼
        $("#imgVerify").attr("src", "${pageContext.request.contextPath }/codeKeyController/getVerify?" + Math.random());
    });

    //獲取驗證碼
    function getVerify(obj) {
        obj.src = "${pageContext.request.contextPath }/codeKeyController/getVerify?" + Math.random();
    }