定义图书类Book，具有属性账号id，书名name、作者author 和价格price和一个图书馆类Library保存新书
/**
* @author:fang
*/
package shixun.project1.zuoye1;
import java.util.*;
public class Library {
public static void main(String[] args) {
HashSet<Book> hashSet=new HashSet<>();
select(hashSet);
// addBook();
}
//功能选择
private static void select(HashSet<Book> hashSet) {
Scanner s=new Scanner(System.in);
System.out.println("功能列表：\n1.插入图书\n2.删除图书\n3.修改图书\n4.查看图书\n请输入对应id选择功能:");
String opt=s.next();
switch (opt){
case "1":
hashSet=addBook(hashSet);
break;
case "2":
deleteBook(hashSet);
break;
case "3":
changeBook(hashSet);
break;
case "4":
checkBook(hashSet);
break;
default:
System.out.println("输入错误，请重新输入!");
select(hashSet);
}
}
//增
private static HashSet<Book> addBook(HashSet<Book> hashSet) {
ArrayList<Book> arrayList=new ArrayList<>(hashSet);
Scanner s=new Scanner(System.in);
do {
System.out.println("插入图书：");
System.out.println("input bookId:");
int id=s.nextInt();
System.out.println("input bookName:");
String name=s.next();
System.out.println("input bookAuthor:");
String author=s.next();
System.out.println("input bookPrice");
double price=s.nextDouble();
hashSet.add(new Book(id,name,author,price));
System.out.println("是否继续插入y/N?");
String isNext=s.next();
if (isNext.equals("n")){
System.out.println("插入完毕！");
select(hashSet);
break;
} else {
if (!isNext.equals("y")) {
System.out.println("请输入正确的指令！");
select(hashSet);
break;
}
System.out.println(hashSet);
}
}while (true);
checkBook(hashSet);
return hashSet;
}
//删
private static HashSet<Book> deleteBook(HashSet<Book> hashSet) {
System.out.println("删除图书");
System.out.println("请输入要删除书籍的ID：");
Scanner s=new Scanner(System.in);
int deleteId=s.nextInt();
ArrayList<Book> arrayList=new ArrayList<>(hashSet);
Collections.sort(arrayList);
Iterator<Book> iterator=arrayList.iterator();
while (iterator.hasNext()){
Book b=(Book) iterator.next();
if(b.getId()==deleteId){
iterator.remove();
}
}
//这里稍微需要注意一下，因为CRUD返回的都是HashSet,所以把删除后的arrayList里面的值重新倒给hashSet，进行输出和返回
hashSet=new HashSet<Book>(arrayList);
checkBook(hashSet);
select(hashSet);
return hashSet;
}
//改
private static void changeBook(HashSet<Book> hashSet) {
System.out.println("修改图书");
select(hashSet);
}
//查
private static void checkBook(HashSet<Book> hashSet) {//,HashSet<Book> hashSet
System.out.println("查看图书");
ArrayList<Book> arrayList=new ArrayList<>(hashSet);
Collections.sort(arrayList);
Iterator<Book> iterator=arrayList.iterator();
while (iterator.hasNext()){
Book book = (Book) iterator.next();
System.out.println(book);
}
select(hashSet);
}
}