登录验证码JAVA代码实现

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import com.shsxt.base.BaseController;

@Controller

public class PicCodeController extends BaseController{

@RequestMapping("picCode")
public void paint(HttpServletRequest request,HttpServletResponse response) throws IOException{
//创建图像缓存区对象（等价于画纸），参数：宽，高，图像类型
BufferedImage bi=new BufferedImage(80,30,BufferedImage.TYPE_USHORT_555_RGB);
//得到制图对象，即画笔
Graphics g=bi.getGraphics();
//设置上下文颜色（背景）
g.setColor(Color.gray);
//填充
g.fillRect(0, 0, 80, 30);

//设置验证码
String code="";
//验证码可取字符
String str="qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM0123456789";
//在字符串中取4个任意字符组成字符串验证码
Random rd=new Random();
for(int i=0;i<4;i++){
code+=str.charAt(rd.nextInt(str.length()));
}
//存入session用于验证登陆
request.getSession().setAttribute("picCode", code);

//设置字体颜色
g.setColor(Color.orange);

g.setFont(new Font("微软雅黑",Font.BOLD,18));
//画验证码
g.drawString(code, 15, 20);

ImageIO.write(bi, "jpeg", response.getOutputStream());

}

}