islogin.java

来自「ssh整合在一起的例子.适合初学者,希望对大家能有一定的帮助作用」· Java 代码 · 共 48 行

package com.softdevelopstudio.util;

import java.io.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import javax.servlet.http.*;
import javax.servlet.*;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

/**
 *
 * <p>Title:判断是否登陆的类 </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2007</p>
 *
 * <p>Company: </p>
 *
 * @author jaco
 * @version 1.0
 */
public class IsLogin extends TagSupport{
    public IsLogin() {
    }

    public int doStartTag() throws JspException {

        HttpSession session = this.pageContext.getSession();
        HttpServletResponse response = (HttpServletResponse)this.pageContext.getResponse();

        if(session.getAttribute("user")==null){
            try {
                String str = "<script language='javascript'>"+
                          "alert('你还没有登陆，或登陆已超时，或者服务器重新启动了,请重新登陆！');"+
                          "top.opener=null;top.close();"+
                          "</script>";
              this.pageContext.getOut().println(str);
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return EVAL_PAGE;
    }

}