managebook.java

在网上书店买书

package Controller;
import java.io.*;
import java.net.*;

import javax.servlet.*;
import javax.servlet.http.*;
import Model.DataOperation;
import java.sql.*;
/**
 *
 * @author Administrator
 * @version
 */
public class ManageBook extends HttpServlet {
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
         DataOperation db=new DataOperation();
        Connection con=db.getConnection();
       String isbn=request.getParameter("ISBN");
        try{
            Statement st=con.createStatement();
            con.setAutoCommit(false);
            ResultSet rs=st.executeQuery("select ISBN from Book where ISBN='"+isbn+"'");
          String dbpwd=null;
            if(rs.next())
            {
            dbpwd=rs.getString("ISBN");
            }
             
            if(dbpwd!=null)
            {  
              String quan=request.getParameter("quantity");
               int quantity=Integer.parseInt(quan);
               st.executeUpdate("update Book" +
                       "set Quantity=Quantity+quantity" +
                       "where ISBN='"+isbn+"'"); 
              out.println("此书目信息已存在，现在已经成功修改了它的库存量");
             }
            else 
            {
             String  publisherID=request.getParameter("PublisherID");
             String  publisherName=request.getParameter("PublisherName");
             String  edition=request.getParameter("Edition");
             String  publicationDate=request.getParameter("PublicationDate");
             double  price=Double.parseDouble(request.getParameter("price"));
             String  bookDescription=request.getParameter("BookDesceiption");
             String  categoryID=request.getParameter("CategoryID"); 
             String categoryName=request.getParameter("CategoryName");
             String  title=request.getParameter("Title"); 
             int  quantity=Integer.parseInt(request.getParameter("quantity"));
             String  authorName=request.getParameter("authorName"); 
             String  authorID=request.getParameter("authorID");
             String image=request.getParameter("image");
             st.execute("set foreign_key_checks=0");
             st.executeUpdate("insert" +" "+
                        "into Book(image,PublisherID,Editon,ISBN,PublicationDate,Price,BookDescription," +
                        "CategoryID,title,quanty)"+" "+
                        "VALUES('"+image+"','"+publisherID+"',"+edition+",'"+isbn+"','"+
                        publicationDate+"',"+price+",'"+bookDescription+"','"+
                        categoryID+"','"+title+"',"+quantity+")");
               
              ResultSet  aut=st.executeQuery("select AuthorID" +" "
                            +"from Author" +" "+
                            "where AuthorID='"+authorID+"'");
              String authorNam=null;
              if(aut.next())
              {
                  authorNam=aut.getString("authorname");
              }
              if(authorNam==null){
                  st.executeUpdate("insert"+" "+
                          "into Author(AuthorID,AuthorName)" +
                          "VALUES('"+authorID+"','"+authorName+"')");
                  
               };
               st.executeUpdate("insert" +" "+
                       "into Writes(AuthorID,ISBN)" +
                       "VALUES('"+authorID+"','"+isbn+"')");
                       out.println("insert" +" "+
                       "into Writes(AuthorID,ISBN)" +
                       "VALUES('"+authorID+"','"+isbn+"')");
                ResultSet rss=st.executeQuery("select CategoryName from Category where CategoryID='"+categoryID+"'");
               String categoryNa=null;
               if(rss.next())
               {
                   categoryNa=rss.getString("CategoryName");
               }
               if(categoryNa==null)
               {
                    st.executeUpdate("insert into category values('"+categoryID+"','"+categoryName+"')");
               }
    
                 ResultSet prs=st.executeQuery("select PublisherName from Publisher where PublisherID='"+publisherID+"'");
                 
               String publisher=null;
               if(prs.next())
               {
                   publisher=rss.getString("PublisherName");
               }
               if(publisher==null)
               {
                    st.executeUpdate("insert into publisher values('"+publisherID+"','"+publisherName+"')");
               }
               st.execute("set foreign_key_checks=1");
              }
          con.commit();
               out.println("已成功将此书插入到书目列表中");
        }
        catch(Exception e)
        {
            out.println("输入数据错误，请重新输入！");
        }
        out.close();
    }
    
    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
}