viewcheckfilter.java

基于struts开发的网上书店系统。希望对大家有帮助。JSP JavaBean Struts

package adminfilter;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class ViewCheckFilter implements Filter {
	protected FilterConfig filterConfig;
	final private String CONTENT_TYPE_HTML = "text/html; charset=gb2312";
	PrintWriter toClientTextOutStream;	
	private String targetEncoding = "gb2312";
	
	public void init(FilterConfig config) throws ServletException {
		// TODO 自动生成方法存根
        this.filterConfig = config;
        this.targetEncoding = config.getInitParameter("encoding");	

	}


	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		// TODO 自动生成方法存根
		//System.out.println("doFilter");
		
		 HttpServletRequest httprequest = (HttpServletRequest)request;
       HttpServletResponse httpresponse = (HttpServletResponse)response;
       HttpSession session = httprequest.getSession();
       String isLogin="";
       //对客户端的请求进行统一的编码
       httprequest.setCharacterEncoding(targetEncoding);	
  	response.setContentType(CONTENT_TYPE_HTML);   		
		
      try
      {  //获得在session中所记录的isLogin属性，该属性由登录部分的代码写入   
        	isLogin=(String)session.getAttribute("right");          
			 if((isLogin!=null) && ! isLogin.equals(""))	//验证成功，继续处理
			 {
			 	chain.doFilter(request,response);
			 }
			 else	//验证不成功，让用户登录。
			 {
				toClientTextOutStream =new PrintWriter(response.getOutputStream()); 
				toClientTextOutStream.print("<script language=\"JavaScript\">");
				toClientTextOutStream.print("alert(\"您未登录，因此不具有权限\");");					
				String targetURL="/book/loginAction.do";
				toClientTextOutStream.print("window.location.href=\""+targetURL+"\";");
				toClientTextOutStream.print("</script>");
      		    toClientTextOutStream.flush();
			 }
		 }
      catch(Exception e)
      {         
        	e.printStackTrace();
      }

	}

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

	
	public void destroy() {
		// TODO 自动生成方法存根
		this.filterConfig=null;
	}

}