loginfilter.java

这是一个用jsp+Oracle开发的联系人客户关系管理系统！

package com.test;

import javax.servlet.FilterChain;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import javax.servlet.FilterConfig;

public class LoginFilter implements Filter
{
	String LOGIN_PAGE = "init.jsp";
	protected FilterConfig filterConfig;

	public void init(FilterConfig config)
	{
		this.filterConfig = config;
	}

	public void doFilter(ServletRequest req,ServletResponse res,FilterChain chain) throws IOException,ServletException
	{
		HttpServletRequest hreq = (HttpServletRequest)req;
		HttpServletResponse hres = (HttpServletResponse)res;
		String isLog = (String)hreq.getSession().getAttribute("isLog");
		if((isLog!=null)&&((isLog.equals("true"))||(isLog=="true")))//检查是否登陆
		{
			chain.doFilter(req,res);
			return;
		}
		else
		{
			hres.sendRedirect(LOGIN_PAGE);//如果没有登陆，把视图派发到登陆页面
		}
	}

	public void destroy()
	{
		this.filterConfig = null;
	}

	public void setFilterConfig(final FilterConfig filterConfig)
	{
		this.filterConfig = filterConfig;
	}
};