9
import java.util.ArrayList; import java.util.List; import java.util.Scanner; public class first { static List<book> a= new ArrayList<book>(); static { book b1 = new book("1", "1", 1); a.add(b1); book b2 = new book("2", "2", 2); a.add(b2); book b3 = new book("3", "3", 3); a.add(b3); } public static void main(String[] args) { mune(); } public static void mune() { for (;;) { System.out.println("***********************"); System.out.println("* 1、添加图书 *"); System.out.println("* 2、删除图书 *"); System.out.println("* 3、修改图书 *"); System.out.println("* 4、查询所有图书 *"); System.out.println("* 5、查询一本图书 *"); System.out.println("* 0、退出程序 *"); System.out.println("***********************"); int i = inputInt("请输入要选择的操作:"); switch (i) { case 1: addbook(); break; case 2: delbook(); break; case 3: updatebook(); break; case 4: findAllbook(); break; case 5: findbookByName(); break; case 0: return; default: System.out.println("请重新输入"); break; } } } private static void findbookByName() { String name = inputStr("请输入要查找的图书名称"); int index = 0; System.out.println("id\t图书名称\t价格"); for (book book : a) { if (name.equals(book.getName())) { System.out.println(book.getId() + "\t" + book.getName() + "\t" + book.getPrice()); } index++; } } private static void findAllbook() { System.out.println("id\t图书名称\t价格"); for (book book : a) { System.out.println(book.getId() + "\t" + book.getName() + "\t" + book.getPrice()); } } private static void updatebook() { String id = inputStr("请输入要修改的图书id"); int index = 0; for (book book : a) { if (id.equals(book.getId())) { book.setName(inputStr("请输入修改后的名称:")); book.setPrice(inputDouble("请输入修改后的价格:")); a.remove(index); a.add(index, book); } index++; } } private static void delbook() { String id = inputStr("请输入要删除的图书id"); int index = 0; for (book book : a) { if (id.equals(book.getId())) { a.remove(index); } index++; } } private static void addbook() { String id = inputStr("请输入图书id"); String name = inputStr("请输入图书名称"); double price = inputDouble("请输入图书价格"); book book = new book(id, name, price); a.add(book); } public static String inputStr(String msg) { System.out.print(msg); return new Scanner(System.in).nextLine(); } public static int inputInt(String msg) { System.out.print(msg); return new Scanner(System.in).nextInt(); } public static double inputDouble(String msg) { System.out.print(msg); return new Scanner(System.in).nextDouble(); } }
public class book { private String id; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } private String name; private double price; public book(String id, String name, double price) { super(); this.id = id; this.name = name; this.price = price; } }
3
create table Book(id int(10),name char(10),price double(10)); insert into Book(id,name,price)values(1,"1",20); delete from Book where name='java'; delete from Book where name like '我%'; delete from Book; update Book set price=18.8 where price>20; select * from Book; select * from Book where price>5;