searchexpense.java

利用java编写的一个学生宿舍管理系统

/**
 * SearchHouse.java
 * author:liuhaijing
 * @version 1.0
 */
 
 package mydesign;//包名

import java.io.*;
import mydesign.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;

public class SearchExpense extends HttpServlet
{
	String strSQL="";
	String strSQL1="";
    
    //Initialize global variables
    public void init() throws ServletException 
    {
    }
    
    //接收POST请求，执行数据库操作，分页显示结果保存到session中，把视图派发到下一个页面
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException
    {
    	HttpSession session=request.getSession(true);
        request.setCharacterEncoding("gb2312");
        response.setContentType("text/html; charset=gb2312");
        PrintWriter out=response.getWriter();
        HouseControl housecontrol=new HouseControl();
        ExpenseControl expensecontrol=new ExpenseControl();
        PageBean pageCt1=new PageBean();
        int page=1;
        String table="";
      
        if(session.getAttribute("strSQL")!=null)    //判断客户机的请求是接受查询表单数据，还是执行翻页、修改或删除
        {
        	strSQL=(String)session.getAttribute("strSQL");
        	if(session.getAttribute("jumppage")==null)    //判断客户机的请求是翻页还是执行修改或删除后的显示
        	{
        		try{
        		String x=request.getParameter("jumppage");    //得到要显示的页码  
        		page=Integer.parseInt(x);
   	     		String update=request.getParameter("update");
   	     		String handin=request.getParameter("handin");
      	  		if(update!=null||handin!=null)    //判断客户机的请示是翻页还是修改或者删除，修改删除执行
        		{        	
        			int select=Integer.parseInt(request.getParameter("select"));
        			pageCt1=(PageBean)session.getAttribute("pageCt1");    //得到该页显示的数据
        			ArrayList search=pageCt1.getResult();
        			Expense expense=(Expense)search.get(select);    //得到要操作的数据
        			session.setAttribute("jumppage",x);    //保存要显示的页码
        			session.setAttribute("expense",expense);
        			if(update!=null)  out.print("<script>window.location.href='updateexpense.jsp'</script>");
        			else  out.print("<script>window.location.href='handin.jsp'</script>");
        		}
        		}catch(Exception e)
        		{
        			System.out.print("SearchExpense Servlet error:"+e.getMessage());
        		}
        	}else{
        			page=Integer.parseInt((String)session.getAttribute("jumppage"));    //得到要显示的页码
         			session.setAttribute("jumppage",null);    //要显示的页码清空
        	}
        }else{    //得到表单数据
        	table=request.getParameter("table");
        	session.setAttribute("table",table);
        	String a1=request.getParameter("donghao");
        	String a2=request.getParameter("houseid");
        	String a3=request.getParameter("ishandin");
        	strSQL=getStrSQL(a1,a2,a3);
        }
        try
        {
        	table=((String)session.getAttribute("table")!=null)?(String)session.getAttribute("table"):table;
        	session.setAttribute("strSQL",strSQL);
        	strSQL1="select count(*) from "+table+strSQL;    //计算查询总数的查询语句
        	strSQL="select top "+page*pageCt1.rowsPerPage+" * from "+table+strSQL;    //第一页到要显示页码的查询语句
         	if(page==0)  out.print("<script>alert('已经无符合条件的记录！');window.location.href='searchexpense.jsp'</script>");    //符合条件的数据为0时将页面派发到查询页面
        	pageCt1=expensecontrol.listData(page,this); 
        	expensecontrol.close();
         	if(pageCt1.getResult().size()==0)  out.print("<script>alert('无符合条件的记录！');window.location.href='searchexpense.jsp'</script>");    //符合条件的数据为0时将页面派发到查询页面
			session.setAttribute("pageCt1",pageCt1);    //保存要显示的数据
        	out.print("<script>window.location.href='searchexpenseresult.jsp'</script>");    //将视图派发到下一个页面
        }
        catch(Exception e)
        {
            System.out.print("SearchExpense Servlet error:"+e.getMessage());            
        }
        finally
        {
        }
    }
    
    //和POST请求的处理一样
    public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException
    {
    	doPost(request,response);
    }
    
	//处理数据
    private String getStrSQL(String a1,String a2,String a3)
    {
    	strSQL="";
		if(!a1.equals(""))
		{
			strSQL=strSQL+" where donghao='"+a1+"'";
			if(!a2.equals("")) strSQL=strSQL+" and houseid='"+a2+"'";
			if(!a3.equals("请选择"))
			{
				if(a3.equals("是")) strSQL=strSQL+" and expense=0";
				else  strSQL=strSQL+" and expense>0";
			}
		}else{
			if(!a2.equals(""))
			{
				strSQL=strSQL+" where houseid='"+a2+"'";
				if(!a3.equals("请选择"))
				{
					if(a3.equals("是")) strSQL=strSQL+" and expense=0";
					else  strSQL=strSQL+" and expense>0";
				}
			}else{
				if(!a3.equals("请选择"))
				{
					if(a3.equals("是")) strSQL=strSQL+" where expense=0";
					if(a3.equals("否")) strSQL=strSQL+" where expense>0";
				}
			}
		}	
		strSQL=strSQL+";";
		return strSQL;
    }
    
    //Clean up resources
    public void destroy()
    {
    }
}