JAVA、SpirngBoot 實現後臺驗證碼接口

最近有個需求，需要返回驗證碼，以前我一直以爲有驗證碼是在前端做的，後面才發現，前端存儲的只是一個圖片，和一個 session 數據，用戶根據圖片輸入內容，前端取出 session 的內容進行校驗，這就是最常見的驗證碼邏輯。

這裏直接創建一個簡單的 springboot 工程。

只要有 spring web 模塊即可

主要工程結構

com.example.verificationcode.VerificationcodeApplication

package com.example.verificationcode;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class VerificationcodeApplication {

    public static void main(String[] args) {
        SpringApplication.run(VerificationcodeApplication.class, args);
    }

}

com.example.verificationcode.VerificationCodeController

package com.example.verificationcode;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;

@Controller
public class VerificationCodeController {


    /**
     * 二維碼接口
     * @param request
     * @param response
     */
    /* 獲取驗證碼圖片*/

    @RequestMapping("/getVerifyCode")
    public void getVerificationCode(HttpServletResponse response,HttpServletRequest request) {

        try {

            int width=200;

            int height=69;

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

            //生成對應寬高的初始圖片

            String randomText = VerifyCode.drawRandomText(width,height,verifyImg);

            //單獨的一個類方法，出於代碼複用考慮，進行了封裝。

            //功能是生成驗證碼字符並加上噪點，干擾線，返回值爲驗證碼字符

            request.getSession().setAttribute("verifyCode", randomText);

            response.setContentType("image/png");//必須設置響應內容類型爲圖片，否則前臺不識別

            OutputStream os = response.getOutputStream(); //獲取文件輸出流

            ImageIO.write(verifyImg,"png",os);//輸出圖片流

            os.flush();

            os.close();//關閉流

        } catch (IOException e) {

            e.printStackTrace();

        }

    }
}

com.example.verificationcode.VerifyCode

package com.example.verificationcode;

/*對圖片進行處理的類和方法*/

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

public class VerifyCode {

    public static  String drawRandomText(int width, int height, BufferedImage verifyImg) {

        Graphics2D graphics = (Graphics2D)verifyImg.getGraphics();

        graphics.setColor(Color.WHITE);//設置畫筆顏色-驗證碼背景色

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

        graphics.setFont(new Font("微軟雅黑", Font.BOLD, 40));

        //數字和字母的組合

        String baseNumLetter= "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

        StringBuffer sBuffer = new StringBuffer();

        int x = 10;  //旋轉原點的 x 座標

        String ch = "";

        Random random = new Random();

        for(int i = 0;i < 4;i++){

            graphics.setColor(getRandomColor());

            //設置字體旋轉角度

            int degree = random.nextInt() % 45;  //角度小於30度

            int dot = random.nextInt(baseNumLetter.length());

            ch = baseNumLetter.charAt(dot) + "";

            sBuffer.append(ch);

            //正向旋轉

            graphics.rotate(degree * Math.PI / 180, x, 45);

            graphics.drawString(ch, x, 45);

            //反向旋轉，不反向旋轉的話字符會跑出畫布
            graphics.rotate(-degree * Math.PI / 180, x, 45);

            x += 48;

        }

        //畫干擾線

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

            // 設置隨機顏色

            graphics.setColor(getRandomColor());

            // 隨機畫線

            graphics.drawLine(random.nextInt(width), random.nextInt(height),

                    random.nextInt(width), random.nextInt(height));

        }

        //添加噪點

        for(int i=0;i<30;i++){

            int x1 = random.nextInt(width);

            int y1 = random.nextInt(height);

            graphics.setColor(getRandomColor());

            graphics.fillRect(x1, y1, 2,2);

        }

        return sBuffer.toString();

    }

    /**
     * 隨機取色
     */

    private static Color getRandomColor() {

        Random ran = new Random();

        Color color = new Color(ran.nextInt(256),

                ran.nextInt(256), ran.nextInt(256));

        return color;

    }

}

測試結果

如果註釋掉

將會出現該情況

源碼地址：https://github.com/weijieqiu/iStudy