图形验证码

图形验证码

package com.penn.study.controller;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import javax.imageio.ImageIO;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.Random;

/**
 * 图形验证码
 */
@RestController("/penn")
public class testController {

    private static final String KEY = "code";

    @Autowired
    private RedisTemplate redisTemplate;

    @RequestMapping(value="/getImageCode", method=RequestMethod.GET)
    @ResponseBody
    public String getImageCode(HttpServletResponse response){
        try {
            BufferedImage image  = createVerifyCode();
            OutputStream out = response.getOutputStream();
            ImageIO.write(image, "JPEG", out);
            out.flush();
            out.close();
            return null;
        }catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    @RequestMapping(value="/checkCode", method=RequestMethod.GET)
    @ResponseBody
    public boolean checkCode(int code){
        Integer codeOld = redisTemplate.opsForValue().get(KEY);
        if(codeOld == null || codeOld - code != 0 ) {
            return false;
        }
        redisTemplate.opsForValue().delete(KEY);
        return true;
    }
    private static BufferedImage createVerifyCode(){
        int width = 80;
        int height = 32;
        //create the image
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        // set the background color
        g.setColor(new Color(0xDCDCDC));
        g.fillRect(0, 0, width, height);
        // draw the border
        g.setColor(Color.black);
        g.drawRect(0, 0, width - 1, height - 1);
        // create a random instance to generate the codes
        Random rdm = new Random();
        // make some confusion
        for (int i = 0; i < 50; i++) {
            int x = rdm.nextInt(width);
            int y = rdm.nextInt(height);
            g.drawOval(x, y, 0, 0);
        }
        // generate a random code
        String verifyCode = generateVerifyCode(rdm);
        g.setColor(new Color(0, 100, 0));
        g.setFont(new Font("Candara", Font.BOLD, 24));
        g.drawString(verifyCode, 8, 24);
        g.dispose();
        //calc result set redis
        int rnd = calc(verifyCode);
        redisTemplate.opsForValue().set(KEY,rnd);
        //输出图片
        return image;
    }

    private static int calc(String exp) {
        try {
            ScriptEngineManager manager = new ScriptEngineManager();
            ScriptEngine engine = manager.getEngineByName("JavaScript");
            return (Integer)engine.eval(exp);
        }catch(Exception e) {
            e.printStackTrace();
            return 0;
        }
    }

    private static char[] ops = new char[] {'+', '-', '*'};

    private static String generateVerifyCode(Random rdm) {
        int num1 = rdm.nextInt(10);
        int num2 = rdm.nextInt(10);
        int num3 = rdm.nextInt(10);
        char op1 = ops[rdm.nextInt(3)];
        char op2 = ops[rdm.nextInt(3)];
        String exp = ""+ num1 + op1 + num2 + op2 + num3;
        return exp;
    }

}