reborrow.java

vb+java实现的图书管理系统

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.bean.util.DateOper;
import com.bean.util.DbConn;

public class Reborrow extends HttpServlet {

	public Reborrow() {
		super();
	}

	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("gbk");
		response.setContentType("text/html;charset=gbk");
		PrintWriter out = response.getWriter();
		
		String message="";
		HttpSession session=request.getSession(true);
		if(session.getAttribute("user")==null){
			response.sendRedirect("index.jsp?contr=myInfo");
		}
		else{
			String readerId=session.getAttribute("user").toString();
			
			String sql="select count(*) as count from BorrowInfo a,BookInfo b,readerInfo r where r.readerId='"+readerId+"' and r.readerId=a.readerId and b.bookId=a.bookId and a.rebacktime is null and datediff(d,a.endtime,GetDate())>0";
			DbConn conn=new DbConn();
			String[][] outtimebookinfo=conn.getData(sql);
			int countBook=Integer.parseInt(outtimebookinfo[0][0]);
			if(countBook>0){
				message="有图书已超期未还，无法续借";
			}
			else{
				int borrowId=Integer.parseInt(request.getParameter("borrowId"));
				sql="select b.BookName,b.author,a.borrowtime,a.endtime,a.reborrowflag,a.borrowId,d.days from BorrowInfo a,BookInfo b,readerInfo c,readerType d where borrowId="+borrowId+" and b.bookId=a.bookId and a.readerId=c.readerId and c.typeId=d.typeId";
				String[][] bookinfo=conn.getData(sql);
				//System.out.print(bookinfo[0][4]);
				if(bookinfo[0][4].equals("N")){
					String firstDate = new String(new SimpleDateFormat("yyyy-MM-dd").format(new Date()));
					String secondDate=bookinfo[0][3];
					int days=(new DateOper()).nDaysBetweenTwoDate(firstDate, secondDate);
					if(days>0){
						Calendar cal = Calendar.getInstance();
						SimpleDateFormat bartDateFormat = new SimpleDateFormat("yyyy-MM-dd");
						Date rightNow=null;
						try {
							rightNow = bartDateFormat.parse(firstDate);
						} catch (ParseException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
						cal.setTime(rightNow);
						cal.add(Calendar.DATE,Integer.parseInt(bookinfo[0][6]));
						String nDaysAfter=bartDateFormat.format(cal.getTime());
						sql="update borrowInfo set endtime='"+nDaysAfter+"',ReBorrowFlag='Y'";
						int count=conn.update(sql);
						if(count>0){
							message="续借成功";
						}
						else{
							message="续借失败，请重试";
						}
					}
					else{
						message="图书已超期，无法续借";
					}
				}
			}
		}
		out.println("<script type=text/javascript>alert('"+message+"');</script>");
		out.println("<meta http-equiv=\"refresh\" content=\"0;url=index.jsp?contr=myInfo&type=borrowInfo\">");
		out.flush();
		out.close();
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

	public void init() throws ServletException {
		// Put your code here
	}

}