Springboot 驗證碼生成圖片格式和base64編碼格式

生成驗證碼：
提供一個接口， 這個接口里，我們將生成的驗證碼存入session，然后將驗證碼以圖片格式或者base64編碼串返回給調用端。

校驗驗證碼：
提供一個接口，這個接口里，我們收到調用端傳過來的校驗碼，然后從session取出驗證碼，兩個驗證碼都全部轉小寫，進行無大小寫區分匹配校驗，返回true/flase 。

存儲驗證碼：
生成的驗證碼，在未生成圖片的時候，就將4位驗證碼字符先存入session，以‘JCCODE’作為存取session的key。

先創建工具類，ValidateCodeUtil.java：

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.io.ByteArrayOutputStream;
import java.util.Base64;
import java.util.Random;
 

public class ValidateCodeUtil {
 
 
    private static Random random = new Random();
    private int width = 165; //驗證碼的寬
    private int height = 45; //驗證碼的高
    private int lineSize = 30; //驗證碼中夾雜的干擾線數量
    private int randomStrNum = 4; //驗證碼字符個數
 
    private String randomString = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWSYZ";
    private final String sessionKey = "JCCODE";
 
    //字體的設置
    private Font getFont() {
        return new Font("Times New Roman", Font.ROMAN_BASELINE, 40);
    }
 
    //顏色的設置
    private static Color getRandomColor(int fc, int bc) {
 
        fc = Math.min(fc, 255);
        bc = Math.min(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 - 12);
 
        return new Color(r, g, b);
    }
 
    //干擾線的繪制
    private void drawLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(20);
        int yl = random.nextInt(10);
        g.drawLine(x, y, x + xl, y + yl);
 
    }
 
    //隨機字符的獲取
    private  String getRandomString(int num){
        num = num > 0 ? num : randomString.length();
        return String.valueOf(randomString.charAt(random.nextInt(num)));
    }
 
    //字符串的繪制
    private String drawString(Graphics g, String randomStr, int i) {
        g.setFont(getFont());
        g.setColor(getRandomColor(108, 190));
        //System.out.println(random.nextInt(randomString.length()));
        String rand = getRandomString(random.nextInt(randomString.length()));
        randomStr += rand;
        g.translate(random.nextInt(3), random.nextInt(6));
        g.drawString(rand, 40 * i + 10, 25);
        return randomStr;
    }
 
 
    //生成隨機圖片
    public void getRandomCodeImage(HttpServletRequest request, HttpServletResponse response){
        HttpSession session = request.getSession();
        // BufferedImage類是具有緩沖區的Image類,Image類是用於描述圖像信息的類
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, width, height);
        g.setColor(getRandomColor(105, 189));
        g.setFont(getFont());
        // 干擾線
        for (int i = 0; i < lineSize; i++) {
            drawLine(g);
        }
        // 隨機字符
        String randomStr = "";
        for (int i = 0; i < randomStrNum; i++) {
            randomStr = drawString(g, randomStr, i);
        }
        System.out.println("隨機字符："+randomStr);
        g.dispose();
        //移除之前的session中的驗證碼信息
        session.removeAttribute(sessionKey);
        //重新將驗證碼放入session
        session.setAttribute(sessionKey, randomStr);
        try {
            //  將圖片以png格式返回,返回的是圖片
            ImageIO.write(image, "PNG", response.getOutputStream());
 
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
 
 
 
     //生成隨機圖片的base64編碼字符串
 
    public String getRandomCodeBase64(HttpServletRequest request, HttpServletResponse response) {
        HttpSession session = request.getSession();
        // BufferedImage類是具有緩沖區的Image類,Image類是用於描述圖像信息的類
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, width, height);
        g.setColor(getRandomColor(105, 189));
        g.setFont(getFont());
        //干擾線
        for (int i = 0; i < lineSize; i++) {
            drawLine(g);
        }
 
        //隨機字符
        String randomStr = "";
        for (int i = 0; i < randomStrNum; i++) {
            randomStr = drawString(g, randomStr, i);
        }
        System.out.println("隨機字符："+randomStr);
        g.dispose();
        session.removeAttribute(sessionKey);
        session.setAttribute(sessionKey, randomStr);
        String base64String = "";
        try {
            //  直接返回圖片
            //  ImageIO.write(image, "PNG", response.getOutputStream());
            //返回 base64
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ImageIO.write(image, "PNG", bos);
 
            byte[] bytes = bos.toByteArray();
            Base64.Encoder encoder = Base64.getEncoder();
            base64String = encoder.encodeToString(bytes);
 
        } catch (Exception e) {
            e.printStackTrace();
        }
 
        return base64String;
    }
 
 
 
    }
 
 
 
 

 

接下來寫接口，創建一個ValidateCodeController.java，
先是生成驗證碼，返回圖片的接口：

import com.example.demo.util.ValidateCodeUtil;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
/**
 * @Author : JCccc
 * @CreateTime : 2019/9/25
 * @Description :
 **/
 
@RestController
public class ValidateCodeController {
 
 
    //返回驗證碼圖片
   @GetMapping("/getCaptchaImg")
   public void getCaptchaImg(HttpServletRequest request, HttpServletResponse response, HttpSession session) {
 
       try {
 
           response.setContentType("image/png");
           response.setHeader("Cache-Control", "no-cache");
           response.setHeader("Expire", "0");
           response.setHeader("Pragma", "no-cache");
           ValidateCodeUtil validateCode = new ValidateCodeUtil();
           // getRandomCodeImage方法會直接將生成的驗證碼圖片寫入response
           validateCode.getRandomCodeImage(request, response);
           // System.out.println("session里面存儲的驗證碼為："+session.getAttribute("JCCODE"));
 
       } catch (Exception e) {
           e.printStackTrace();
       }
 
   }
 
 
}
 
 
 
 

用postman來調用下接口，

可以看到控制台的打印，這個驗證碼字符串已經存入了session（在后面的驗證接口有介紹取值）
 

接下來是編寫一個校驗驗證碼接口：

    //驗證碼校驗
    @GetMapping("/checkCaptcha")
    public boolean getCheckCaptcha(@RequestParam("code") String code, HttpSession session) {
 
        try {
            //toLowerCase() 不區分大小寫進行驗證碼校驗
            String sessionCode= String.valueOf(session.getAttribute("JCCODE")).toLowerCase();
            System.out.println("session里的驗證碼："+sessionCode);
            String receivedCode=code.toLowerCase();
            System.out.println("用戶的驗證碼："+receivedCode);
            return !sessionCode.equals("") && !receivedCode.equals("") && sessionCode.equals(receivedCode);
 
        } catch (Exception e) {
 
            return false;
        }
 
    }

用postman調下接口，先生成驗證碼模擬返回給頁面了，

然后調用校驗驗證碼接口，模擬用戶在頁面輸入驗證碼，

可以看到校驗正確。

 

返回base64編碼串的接口：

    // 生成驗證碼,返回的是 base64
    @GetMapping("/getCaptchaBase64")
    public Object getCaptchaBase64(HttpServletRequest request, HttpServletResponse response) {
 
        Map result = new HashMap();
        try {
 
            response.setContentType("image/png");
            response.setHeader("Cache-Control", "no-cache");
            response.setHeader("Expire", "0");
            response.setHeader("Pragma", "no-cache");
            ValidateCodeUtil validateCode = new ValidateCodeUtil();
            // 返回base64
            String base64String = validateCode.getRandomCodeBase64(request, response);
            result.put("url", "data:image/png;base64," + base64String);
            result.put("message", "created successfull");
           //http://tool.chinaz.com/tools/imgtobase/  base64直接轉為圖片網站
            System.out.println("結果：" + result.get("url"));
 
        } catch (Exception e) {
            System.out.println(e);
        }
 
        return result;
    }

用postman調用一下，

控制台打印：

將url取出來，

data:image/png;base64,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

去base64編碼串轉圖片的網站去看看，對應的驗證碼圖：