java实现登录验证码

java实现登录验证码

本文实例为大家分享了java实现登录验证码的具体代码，供大家参考，具体内容如下

1、ValidateCode.java

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.OutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import org.springframework.stereotype.Service;

/**

* 登录验证码

*

*/

public class ValidateCode {

/**

* 得到验证码图片

* @param out

* @param number 验证数字

* @throws ServletException

* @throws IOException

*/

public void getImage(OutputStream out,String number)

throws ServletException, IOException {

//0.创建空白图片

BufferedImage image=new BufferedImage(100,30,BufferedImage.TYPE_INT_RGB);

//1.获取图片画笔

Graphics g = image.getGraphics();

Random r=new Random();

/http:///2.设置画笔颜色(Random类中的nextInt(n)返回一个大于等于0，小于n的随机数)

g.setColor(new Color(r.nextInt(255),r.nextInt(255), r.nextInt(255)));

//3.绘制矩形的背景

g.fillRect(0, 0, 100, 30);

//4.调用自定义的方法，获取长度为4的字母数字组合的字符串

g.setColor(new Color(0,0,0));

g.setFont(new Font(null,Font.BOLD,24));

//5.设置颜色字体后，绘制字符串（x/y,最左边字符所处的位置）

g.drawString(number, 20, 24);

//6.绘制8条干扰线(alpha表示透明度)

for(int i=0;i<8;i++){

g.setColor(new Color(r.nextInt(255),r.nextInt(255), r.nextInt(255),r.nextInt(255)));

g.drawLine(r.nextInt(100), r.nextInt(30), r.nextInt(100), r.nextInt(30));

}

ImageIO.write(image, "jpeg", out);

}

//自定义方法，获取长度为size的字母数字组合的字符串

public String getNumber(int size){

String str="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

String number="";

Random r = new Random();

for(int i=0;i

number+=str.charAt(r.nextInt(str.length()));

}

return number;

}

}

2、Controller

@RequestMapping(value = "/check",method={RequestMethod.GET})

@ResponseBody

public void check(HttpServletRequest req) {

try {

HttpServletResponse response = this.getResponse();

response.setContentType("application/octet-stream");

response.addHeader("Content-Disposition", "attachment;filename=" + "vcode.jpeg");

String number = validateCode.getNumber(4);

validateCode.getImage(response.getOutputStream(),number);

} catch (Exception e) {

}

}

3、html

效果图

number+=str.charAt(r.nextInt(str.length()));

}

return number;

}

}

2、Controller

@RequestMapping(value = "/check",method={RequestMethod.GET})

@ResponseBody

public void check(HttpServletRequest req) {

try {

HttpServletResponse response = this.getResponse();

response.setContentType("application/octet-stream");

response.addHeader("Content-Disposition", "attachment;filename=" + "vcode.jpeg");

String number = validateCode.getNumber(4);

validateCode.getImage(response.getOutputStream(),number);

} catch (Exception e) {

}

}

3、html

效果图

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