bookborrow.java

基于jsp的图书管理系统的功能和实现

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*; 
import java.sql.*;
import data.LoginData;
public class BookBorrow extends HttpServlet{
	private static final String CONTENT_TYPE="text/html;charset=GBK";
	public void doPost(HttpServletRequest request,HttpServletResponse response)
	throws ServletException,IOException{
		String strSql=null;
		String strSql1=null;
		String stautes=null;
		ResultSet rs=null;
		ResultSet rs1=null;
		Statement stmt=null;
		Statement stmt1=null;
		int result=0;
		int result1=0;
		int rnum=0;
		int bnum=0;
		int maxnum=0;
		request.setCharacterEncoding("GBK");
    	String BcRnumber =request.getParameter("BcRnumber");
		String BcBnumber =request.getParameter("BcBnumber");
		String BcBname = request.getParameter("BcBname");
	
        HttpSession session =request.getSession(false);
         if(session==null)
        {
         response.sendRedirect("tushu/error.jsp");
         return;
        }
        session.setAttribute("Bcr",BcRnumber);
        session.setAttribute("Bcb", BcBname);
		LoginData loginData = new LoginData();
		Connection conn = loginData.getConn();
        try{
             
             stmt = conn.createStatement();
             stmt1=conn.createStatement();
             strSql="SELECT * FROM Book WHERE Bnumber='"+BcBnumber+"'"+" "+"and Bstate=1";
             strSql1="select * from Reader where Rnumber='"+BcRnumber+"'"+" "+"and Rlimited>Ryamount";
		     rs=stmt.executeQuery(strSql); 
             rs1=stmt1.executeQuery(strSql1);
          	 /*****************************************************/		
   
             if(rs.next()&&rs1.next()){
             	
             	        strSql="UPDATE Book SET Bstate=0"+" "+"WHERE Bnumber='"+BcBnumber+"'";
			   	        result=stmt.executeUpdate(strSql);
			   	        strSql1="UPDATE Reader SET Ryamount=Ryamount+1"+" "+"where Rnumber='"+BcRnumber+"'";
			   	        result1=stmt1.executeUpdate(strSql1);
			   	        if(result>0&&result1>0){
			   	        	    strSql="insert into Bcurrent(BcRnumber,BcBnumber,BcBname) values('"+BcRnumber+"','"+BcBnumber+"','"+BcBname+"')";
			   	        	    result=stmt.executeUpdate(strSql);
			   	        	    if(result>0){
			   	        	  
			   	        	    	   stautes ="借书成功!";
			   	  	                   session.setAttribute("Modify",stautes);
			   		   	               response.sendRedirect("tushu/BorrowBook_Sucess.jsp");
			   	        	    	}
			   	        	    	else{
			   	        	    		 strSql="UPDATE Book SET Bstate=1"+" "+"WHERE Bnumber='"+BcBnumber+"'";
			   	                         result=stmt.executeUpdate(strSql);
			   	                         strSql1="UPDATE Reader SET Ryamount=Ryamount-1"+" "+"where Rnumber='"+BcRnumber+"'";
			   	                         result1=stmt1.executeUpdate(strSql1);
			   	                         stautes ="借书失败,系统问题,请下次借书!";
			   	  	                     session.setAttribute("Modify",stautes);
			   		                     response.sendRedirect("tushu/BorrowBook_Sucess.jsp");
			   	        	    		
			   	        	    		}

			   	        	}
			   	        	else{
			   	        		  stautes ="借书失败,系统问题,请下次借书!";
			   	  	              session.setAttribute("Modify",stautes);
			   		              response.sendRedirect("tushu/BorrowBook_Sucess.jsp");
			   	        		
			   	        		}



			   	        
             	}
              else {
                      	stautes ="您借的书不在库,请下次借书!";
			   		  	session.setAttribute("Modify",stautes);
			   		    response.sendRedirect("tushu/BorrowBook_Sucess.jsp");
			   		}
		
			   
		   }catch(Exception ex){
		   	ex.printStackTrace();
		   	}
		
		}
		public void destroy(){
			}
	
	}