Java初学者：图书管理小工具代码

1.Welcome.java
import java.util.Date;
import java.util.Scanner;

public class Welcome {
/**
* @param args
* @throws IOException
*/
public static void main(String[] args){
// TODO Auto-generated method stub

System.out.println("Welcome to visit software of book management!\n");
System.out.println("Now is "+new Date()+"\n");
Select s=new Select();
s.SelectService();
}
}

2.Select.java
import java.util.Scanner;
public class Select {
ReturnBook rb=new ReturnBook();
InquireBook ib=new InquireBook();
LendBook lb=new LendBook();
ShowAllBooks sab=new ShowAllBooks();
AddBook ab=new AddBook();
ShowLentBooks slb=new ShowLentBooks();
public void SelectService()
{
System.out.println("1.Show all the books\n2.Inquire book\n3.Lend book\n4.Return book\n5.Add book\n" +
"6.Show lent books");
System.out.print("Please select one from services listed above:");
Scanner s=new Scanner(System.in);
int selectNumber=s.nextInt();

if(selectNumber==1)
{
sab.ShowAll();
}
else if(selectNumber==2)
{
ib.Inquire();
}
else if(selectNumber==3)
{
lb.Lend();
}
else if(selectNumber==4)
{
rb.returnBook();
}
else if(selectNumber==5)
{
ab.add();
}
else if(selectNumber==6)
{
slb.ShowLent();
}
else
{
System.out.println("Input error,Please select one from services listed below again.");
Select ss=new Select();
ss.SelectService();
}
}
}

3.AddBook.java
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.