checklogin.java

简单实现的一个登录模块

//checkLogin.java

//import required classes
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

//class checkLogin
public class checkLogin
{
	public String username = "";

	public boolean check(HttpServletRequest req,HttpServletResponse res)
	throws IOException,ServletException
	{
		String cookieName = "username";
		Cookie[] myCookies = req.getCookies();
		this.username = this.getCookieValue(myCookies,cookieName,"not found");
		PrintWriter out = res.getWriter();
		if(this.username != null)
		{
			//out.println("早上好，" + this.username + "！");
			return true;
			}else{
				out.println("登陆失败！");
				return false;
			}

		}

		public String getUserName()
		{
			return this.username;
		}

		public static String getCookieValue(Cookie[] cookies,String cookieName,String defaultValue)
		{
			for(int i=0;i<cookies.length;i++) {
				Cookie cookie = cookies[i];
				if (cookieName.equals(cookie.getName()))
				return(cookie.getValue());
			}
			return(defaultValue);
		}
	}