spring框架的java登录验证码怎么写

Question

如题所述

Answer 1

可以参考下下面的代码，这个代码是servlet生成的，稍微修改下就能用的

package servlet;

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 javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class CodeServlet extends HttpServlet {

public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

BufferedImage image=new BufferedImage(100, 30, BufferedImage.TYPE_INT_RGB);
Graphics g=image.getGraphics();
Random r=new Random();
g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
g.fillRect(0, 0, 100, 30);
g.setColor(new Color(255,255,255));
g.setFont(new Font(null,Font.BOLD,24));
String code=getCode();
HttpSession session=request.getSession();
session.setAttribute("textcode", code);

g.drawString(code, 10, 25);
response.setContentType("image/jpeg");
OutputStream os=response.getOutputStream();
ImageIO.write(image, "jpeg", os);
os.close();
}
//随机生成验证码字符串的类
public static String getCode(){
char[] letters={'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'};
String code="";
boolean[] bool=new boolean[letters.length];

for(int i=0;i<5;i++){
int num ;
do{
num=(int)(Math.random()*(letters.length));
}while(bool[num]);
code+=letters[num];
bool[num]=true;
}
return code.toUpperCase();
}

}