librarybooks.java

一个简单的图书管管理系统~是用java语言编写的

package library;

import java.sql.*;

import java.util.ArrayList;

public class LibraryBooks {
     // This ArrayList store all books names in library
     private ArrayList <LibraryBooks> books = new ArrayList <LibraryBooks>();
    
     private String dbUrl = "jdbc:postgresql://localhost/library";
    
     private String dbUser = "postgres";
    
     private String dbPwd = "123";
    
     Connection con = null;
    
     PreparedStatement prepStmt = null;
    
     ResultSet rs = null;
    
     private String name;
     private String isbn;
    
     public LibraryBooks(){
        
     }
    
     public LibraryBooks(String isbn,String name){
         this.name = name;
         this.isbn = isbn;
     }
    
     public Connection getConnection() throws Exception {
         return DriverManager.getConnection(dbUrl, dbUser, dbPwd);
     }
    
     public void closeConnection(Connection con) {
         try {
             if (con != null)
                 con.close();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
    
     public void closeResultSet(ResultSet rs) {
         try {
             if (rs != null)
                 rs.close();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
    
     public void closePrepStmt(PreparedStatement prepStmt) {
         try {
             if (prepStmt != null)
                 prepStmt.close();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
    
     // Get all books
     public ArrayList <LibraryBooks> getAllBooks() throws Exception {
         try {  
             Class.forName("org.postgresql.Driver").newInstance();
      

             con = getConnection();
             String selectStatement = "select * from Title5";
             prepStmt = con.prepareStatement(selectStatement);
             rs = prepStmt.executeQuery();
             while (rs.next()) {
                 LibraryBooks book = new LibraryBooks(rs.getString(2),rs.getString(4));
                
                 books.add(book);
             }
             return books;
         } finally {
             closeResultSet(rs);
             closePrepStmt(prepStmt);
             closeConnection(con);
         }
        
     }
    
     public String getTitle(String isbn) throws Exception {
         try {
        	 Class.forName("org.postgresql.Driver").newInstance();
             con = getConnection();
             String selectStatement = "select * from Title5 where isbn=?";
             prepStmt = con.prepareStatement(selectStatement);
             prepStmt.setString(1,isbn);
             rs = prepStmt.executeQuery();
             if (rs.next()) {
                 String name = rs.getString(4);
                 return name;
             } else{
                 return "not in";
             }
         } finally {
             closeResultSet(rs);
             closePrepStmt(prepStmt);
             closeConnection(con);
         }
        
     }
    
     public String getName() {
         return name;
     }
    
     public String getISBN(){
         return isbn;
     }

}