java 生成图片登录校验码

package com.common.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 生成验证码的公用类
 * @author julong
 * @date 2018-5-31 下午5:33:24
 */
public class CaptchaUtils {

  //日志
  private static final Logger logger = LoggerFactory.getLogger(CaptchaUtils.class);
  /**
   * @author julong
   * @date 2018-5-31 下午5:33:21
   */
  private static final String[] CODE = {
                      "1","2","3","4","5","6","7","8","9","0",
                      "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",
                      "1","2","3","4","5","6","7","8","9","0",
                      "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",
                      "1","2","3","4","5","6","7","8","9","0"                   
  };


  public String captcha = "";


  //当前对象
  private static CaptchaUtils instance = null;

  /**
   * 单例化对象
   * @return
   * @author julong
   * @date 2016年5月11日 上午11:50:48
   */
  public static synchronized CaptchaUtils getInstance() {
    if (null == instance) {
      instance = new CaptchaUtils();
    }
    return instance;
  }


  private CaptchaUtils() {

  }

  /**
   * 生成验证码的方法
   * @param width 宽度
   * @param height 高度
   * @return BufferedImage
   * @author julong
   * @date 2018-5-31 下午5:33:46
   */
  public BufferedImage createImage(int width,int height){
    logger.info("【验证码】-开始生成验证码");
    StringBuffer sb = new StringBuffer();  
    Random random = new Random();  
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  
    //创建画布
    Graphics graphic = image.getGraphics();  
    graphic.setColor(Color.getColor("FFF8DC"));  
    graphic.fillRect(0, 0, width, height);  
    Color[] colors = new Color[] { Color.BLUE, Color.GRAY, Color.GREEN, Color.RED, Color.BLACK, Color.ORANGE,Color.CYAN }; 
    for (int i = 0; i < 50; i++) {  
      graphic.setColor(colors[random.nextInt(colors.length)]);  
      final int x = random.nextInt(100);  
      final int y = random.nextInt(80);  
      final int w = random.nextInt(20);  
      final int h = random.nextInt(20);  
      final int signA = random.nextBoolean() ? 1 : -1;  
      final int signB = random.nextBoolean() ? 1 : -1;  
      graphic.drawLine(x, y, x + w * signA, y + h * signB);  
    }  
    // 在 "画板"上绘制字母  
    graphic.setFont(new Font("楷体", Font.BOLD, 30));  
    for (int i = 0; i < 4; i++) {  
      String rand = String.valueOf(CaptchaUtils.CODE[random.nextInt(CaptchaUtils.CODE.length-1)]); 
      sb.append(rand);  
      graphic.setColor(colors[random.nextInt(colors.length)]);  
      graphic.drawString(rand, i * (width / 4), height - (height / 3));  
    }  
    graphic.dispose();  
    this.captcha = sb.toString();
    logger.info("【验证码】-生成验证码结束:{}",sb.toString());
    return image;
  }













  public String getCaptcha() {
    return captcha;
  }


  public void setCaptcha(String captcha) {
    this.captcha = captcha;
  }


  public static void main(String[] args){

    BufferedImage image = CaptchaUtils.getInstance().createImage(120,60);
    try {
      ImageIO.write(image, "JPEG", new File("D:/111.png"));
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }

  }
}

上边为公用校验码类 下来再action中的写法

/**
   * 生成验证码的方法
   * @param request
   * @param response
   * @author julong
   * @date 2018-5-31 下午6:22:15
   */
  @RequestMapping("/captcha")
  @ResponseBody
  @LoggerProxy(method = LoggerMethod.LOGIN,module = LoggerModule.SYSTEM_LOGIN)
  public void captcha(HttpServletRequest request,HttpServletResponse response){
    response.setContentType("JPEG");
    BufferedImage image = CaptchaUtils.getInstance().createImage(100, 38);
    try {
      request.getSession().setAttribute("CODE", CaptchaUtils.getInstance().captcha);
      ImageIO.write(image, "JPEG", response.getOutputStream());
    } catch (IOException e) {
      // TODO Auto-generated catch block
      logger.error("【登录模块】-生成验证码发生异常：",e);
    }
  }

界面中的写法

<img src="http://blog.163.com/xiao_long/blog/login/captcha.html" οnclick="code(this)" style="width:100%;height:31px;padding:0px;margin:0px;"/>

function code(obj){
      var param = getSystemParam();
      obj.src="http://blog.163.com/xiao_long/blog/login/captcha.html?param="+param;
    }