pagerfilter.java

这是一个jbpm的高级应用,是一个oa工作流的系统,里面用到了spring,hibernate技术等.实为学习jbpm的好资料!

package com.bjsxt.oa.web;

import java.io.IOException;

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 com.bjsxt.oa.SystemContext;

/**
 * 用于分页处理的过滤器
 * @author Administrator
 *
 */
public class PagerFilter implements Filter {

	public void destroy() {
	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		
		HttpServletRequest httpRequest = (HttpServletRequest)request;
		
		//获取offset和pagesize的值，并将这些值放入ThreadLocal中
		SystemContext.setOffset(getOffset(httpRequest));
		SystemContext.setPagesize(getPagesize(httpRequest));
		
		try {
			//继续往下执行
			chain.doFilter(request, response);
		} finally {
			//清空ThreadLocal中的值
			SystemContext.removeOffset();
			SystemContext.removePagesize();
		}

	}

	public void init(FilterConfig arg0) throws ServletException {
	}
	
	protected int getOffset(HttpServletRequest request){
		int offset = 0;
		try {
			offset = Integer.parseInt(request.getParameter("pager.offset"));
		} catch (Exception e) {
		}
		return offset;
	}
	
	protected int getPagesize(HttpServletRequest request){
		return 10;
	}
}