本文使用 Java 实现一个简易图书管理系统
一、思路
简易图书管理系统说白了其实就是 用户 与 图书 这两个对象之间的交互
书的属性有
书名
作者
类型
价格
借阅状态
而用户可以分为
普通用户
管理员
使用数组将书统一管理起来
用户对这个数组进行操作
普通用户可以进行
查看所有书籍
借阅书籍
归还书
退出系统
而管理员可以进行普通用户的所有操作，此外
增加书籍
删除书籍
大致如此
二、实现
2.1 创建对象
2.1.1 书
public class Book {
private String name;//书名
private String author;//作者
private double price;//价格
private String type;//类型
boolean IsBorrowed;//借出状态
}
书需要构造方法
以及重写 toString,方便输出
public class Book {
private String name;//书名
private String author;//作者
private double price;//价格
private String type;//类型
boolean IsBorrowed;//借出状态
//构造方法
//书一开始的状态都是未借出
//boolean类型在不赋值的情况下默认人为false
public Book(String name, String author, double price, String type) {
this.name = name;
this.author = author;
this.price = price;
this.type = type;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type + '\'' +
((IsBorrowed == true)?"已接触":"未借出") +
'}';
}
}
为方便管理，将所有与书有关的类放到同一个包下面去
package book;
public class Book {
private String name;//书名
private String author;//作者
private double price;//价格
private String type;//类型
boolean IsBorrowed;//借出状态
//构造方法
//书一开始的状态都是未借出
//boolean类型在不赋值的情况下默认人为false
public Book(String name, String author, double price, String type) {
this.name = name;
this.author = author;
this.price = price;
this.type = type;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type + '\'' +
((IsBorrowed == true)?"已接触":"未借出") +
'}';
}
}目前就是如此
其他方法在实现用户与图书交互时进行补充
2.1.2 用户
为方便管理，将用户相关类放到另一个包中
用户与管理员在属性上是相同的
那么就可以继承于一个抽象类
package user;
abstract public class User {
protected String name;
public User(String name) {
this.name = name;
}
}
package user;
public class NormalUser extends User {
public NormalUser(String name) {
super(name);
}
}
package user;
public class Administrator extends User{
public Administrator(String name) {
super(name);
}
}
可能用到的方法依旧是在后文中进行补充
2.2 交互
2.2.1 操作界面
用户在登陆时会检测身份
public static User login(){
System.out.println("欢迎使用图书管理系统！！！");
Scanner scanner = new Scanner(System.in);
System.out.println("请输入您的姓名");
String name = scanner.nextLine();
System.out.println("请选择你的身份");
System.out.println("1.普通用户");
System.out.println("2.管理员");
int choice = scanner.nextInt();
if(choice == 1){
return new NormalUser (name);
}
else if(choice == 2){
return new Administrator(name);
}
else {
System.out.println("输入的值无效");
}
return null;
}无论是管理员还是普通用户都会有操作界面
那就可以将这个方法作为抽象方法放在 User 类中
package user;
abstract public class User {
protected String name;
public User(String name) {
this.name = name;
}
abstract public void menu();
}
在子类中实现
package user;
public class NormalUser extends User {
public NormalUser(String name) {
super(name);
}
@Override
public void menu() {
System.out.println("请选择操作");
System.out.println("1.显示图书");
System.out.println("2.借阅图书");
System.out.println("3.归还图书");
System.out.println("4.查找图书");
System.out.println("0.退出系统！");
}
}
package user;
public class Administrator extends User{
public Administrator(String name) {
super(name);
}
@Override
public void menu() {
System.out.println("请选择操作");
System.out.println("1.显示图书");
System.out.println("2.借阅图书");
System.out.println("3.归还图书");
System.out.println("4.查找图书");
System.out.println("5.增加图书");
System.out.println("6.删除图书");
System.out.println("0.退出系统！");
}
}测试
public static void main(String[] args) {
User user = login();
user.menu();
}
2.2.2 书架
将书放到一个数组中方便管理
定义一个书架类
这个书架中默认会有几本书
书架有默认容量和已存书本数量
package book;
public class BookList {
private final int defaultcapacity = 10;//默认容量
protected Book[] booklist = new Book[defaultcapacity];
private int usespace;//已存书本容量
public BookList() {
this.booklist[0] = new Book("三体", "刘慈欣", 18.88, "小说");
this.booklist[1] = new Book("西游记", "吴承恩", 17.77, "小说");
this.booklist[2] = new Book("红楼梦", "曹雪芹", 16.66, "小说");
usespace = 3;
}
public int usesize(){
return this.usespace;
}
public int size(){
return this.booklist.length;
}
}
所有操作实际上都是对 booklist 这个数组进行
2.2.3 对图书操作
无论是管理员还是普通用户的操作
都可以理解成一种行为的多态
那就可以用一个接口
package behavior;
import book.BookList;
public interface Behavior{
void work();//各种操作
BookList booklist = new BookList();
}
所有的操作都是实现了这个接口的类
public class AddBehavior implements Ibehavior{
@Override
public void work() {
System.out.println("添加图书");
}
}
public class BorrowedBehavior implements Ibehavior{
@Override
public void work() {
System.out.println("借阅图书");
}
}
public class ExitBehavior implements Ibehavior{
@Override
public void work() {
System.out.println("退出系统！");
}
}
public class RemoveBehavior implements Ibehavior{
@Override
public void work() {
System.out.println("归还图书！");
}
}
public class ReturnBehavior implements Ibehavior{
@Override
public void work() {
System.out.println("归还图书");
}
}
public class ShowBehavior implements Ibehavior{
@Override
public void work() {
System.out.println("展示未借阅的图书！");
}
}
public class FindBehavior implements Behavior{
@Override
public void work() {
System.out.println("查找图书！");
}
}
2.2.4 具体实现对图书操作
普通用户与管理员有对应的操作
可以在普通用户类与管理员类中创建一个数组
public class Administrator extends User{
public Administrator(String name) {
super(name);
}
protected Behavior[] behaviors = {new ExitBehavior(),new ShowBehavior(),new BorrowedBehavior(),new ReturnBehavior(),new FindBehavior(),new AddBehavior(),new RemoveBehavior()};
@Override
public void menu() {
System.out.println("请选择操作");
System.out.println("1.显示图书");
System.out.println("2.借阅图书");
System.out.println("3.归还图书");
System.out.println("4.查找图书");
System.out.println("5.增加图书");
System.out.println("6.删除图书");
System.out.println("0.退出系统！");
}
}
public class NormalUser extends User {
public NormalUser(String name) {
super(name);
}
protected Behavior[] behaviors = {new ExitBehavior(),new ShowBehavior(),new BorrowedBehavior(),new ReturnBehavior(),new FindBehavior()};
@Override
public void menu() {
System.out.println("请选择操作");
System.out.println("1.显示图书");
System.out.println("2.借阅图书");
System.out.println("3.归还图书");
System.out.println("4.查找图书");
System.out.println("0.退出系统！");
}
}这里就需要对应的下标值来对数组进行操作
而对应下标值可以通过 menu 方法来返回
修改一下就可以了
public class Administrator extends User{
public Administrator(String name) {
super(name);
}
protected Behavior[] behaviors = {new ExitBehavior(),new ShowBehavior(),new BorrowedBehavior(),new ReturnBehavior(),new FindBehavior(),new AddBehavior(),new RemoveBehavior()};
@Override
public int menu() {
System.out.println("请选择操作");
System.out.println("1.显示图书");
System.out.println("2.借阅图书");
System.out.println("3.归还图书");
System.out.println("4.查找图书");
System.out.println("5.增加图书");
System.out.println("6.删除图书");
System.out.println("0.退出系统！");
Scanner scanner = new Scanner(System.in);
int choice = scanner.nextInt();
return choice;
}
@Override
public void DoBehavior(int choice){
this.behaviors[choice].work();
}
}public class NormalUser extends User {
public NormalUser(String name) {
super(name);
}
protected Behavior[] behaviors = {new ExitBehavior(),new ShowBehavior(),new BorrowedBehavior(),new ReturnBehavior(),new FindBehavior()};
@Override
public int menu() {
System.out.println("请选择操作");
System.out.println("1.显示图书");
System.out.println("2.借阅图书");
System.out.println("3.归还图书");
System.out.println("4.查找图书");
System.out.println("0.退出系统！");
Scanner scanner = new Scanner(System.in);
int choice = scanner.nextInt();
return choice;
}
@Override
public void DoBehavior(int choice){
this.behaviors[choice].work();
}
}
对各项操作进行实现
2.2.4.1 退出系统（即结束程序）
public class ExitBehavior implements Behavior{
@Override
public void work() {
System.out.println("退出系统！");
System.exit(0);
}
}测试
2.2.4.2 查找图书
根据书名进行对应图书查找
需要拿到书名
在 Book 与 BookList 中增加方法
public class Book {
private String name;//书名
private String author;//作者
private double price;//价格
private String type;//类型
boolean IsBorrowed;//借出状态
//构造方法
//书一开始的状态都是未借出
//boolean类型在不赋值的情况下默认人为false
public Book(String name, String author, double price, String type) {
this.name = name;
this.author = author;
this.price = price;
this.type = type;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type + '\'' +
((IsBorrowed == true)?"已接触":"未借出") +
'}';
}
public String getName(){
return this.name;
}
}
package book;
public class BookList {
private final int defaultcapacity = 10;//默认容量
protected Book[] booklist = new Book[defaultcapacity];
private int usespace;//已存书本容量
public BookList() {
this.booklist[0] = new Book("三体", "刘慈欣", 18.88, "小说");
this.booklist[1] = new Book("西游记", "吴承恩", 17.77, "小说");
this.booklist[2] = new Book("红楼梦", "曹雪芹", 16.66, "小说");
usespace = 3;
}
public int usesize(){
// 存放书本数量
return this.usespace;
}
public int size(){
// 书架总容量
return this.booklist.length;
}
public String getBookName(int index){
// 返回对应位置的书名
return this.booklist[index].getName();
}
public Book getBook(int index){
// 返回对应位置的书
return this.booklist[index];
}
}
package behavior;
import java.util.Scanner;
public class FindBehavior implements Behavior{
@Override
public void work() {
System.out.println("查找图书！");
Scanner scanner = new Scanner(System.in);
System.out.println("请输入你要查找的书籍名称：");
String name = scanner.nextLine();
for (int i = 0; i < booklist.usesize(); i++) {
if(name.equals(booklist.getBookName(i))){
System.out.println("已找到您要查找的图书");
System.out.println(booklist.getBook(i));
return;
}
}
System.out.println("没有您要查找的书籍");
}
}
测试
2..2.4.3 打印图书
将书架上所有书打印出来
只展示没有被借出的图书
那就需要获得书的借出状态
public class Book {
private String name;//书名
private String author;//作者
private double price;//价格
private String type;//类型
boolean IsBorrowed;//借出状态
//构造方法
//书一开始的状态都是未借出
//boolean类型在不赋值的情况下默认人为false
public Book(String name, String author, double price, String type) {
this.name = name;
this.author = author;
this.price = price;
this.type = type;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type + '\'' +
((IsBorrowed == true)?"已接触":"未借出") +
'}';
}
public String getName(){
return this.name;
}
public Boolean IsBorrowed(){
return this.IsBorrowed;
}
}
package behavior;
public class ShowBehavior implements Behavior{
@Override
public void work() {
System.out.println("展示未借阅的图书！");
for (int i = 0; i < booklist.usesize(); i++) {
if(!booklist.getBook(i).IsBorrowed()){
System.out.println(booklist.getBook(i));
}
}
}
}
测试
2.2.4.4 借阅与归还图书
查找到对应图书
修改该书的 IsBorrowed 属性即可
需要在 Book 中增加 set 方法
package book;
public class Book {
private String name;//书名
private String author;//作者
private double price;//价格
private String type;//类型
boolean IsBorrowed;//借出状态
//构造方法
//书一开始的状态都是未借出
//boolean类型在不赋值的情况下默认人为false
public Book(String name, String author, double price, String type) {
this.name = name;
this.author = author;
this.price = price;
this.type = type;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type + '\'' +
((IsBorrowed == true)?"已接触":"未借出") +
'}';
}
public void setBorrowed_borrow(){
this.IsBorrowed = true;
}
public void setBorrowed_return(){
this.IsBorrowed = false;
}
public String getName(){
return this.name;
}
public Boolean IsBorrowed(){
return this.IsBorrowed;
}
}
package behavior;
import java.util.Scanner;
public class ReturnBehavior implements Behavior {
@Override
public void work() {
System.out.println("归还图书");
System.out.println("请输入您要归还的图书名称：");
Scanner scanner = new Scanner(System.in);
String name = scanner.nextLine();
for (int i = 0; i < booklist.usesize(); i++) {
if (name.equals(booklist.getBookName(i)) && !booklist.getBook(i).IsBorrowed()){
System.out.println("本系统已录入该图书");
return;
}
if (name.equals(booklist.getBookName(i))) {
booklist.getBook(i).setBorrowed_return();
System.out.println("归还成功！");
return;
}
}
System.out.println("这本书不属于本系统！");
}
}
package behavior;
import java.util.Scanner;
public class BorrowedBehavior implements Behavior {
@Override
public void work() {
System.out.println("借阅图书");
System.out.println("请输入您要借阅的图书名称：");
Scanner scanner = new Scanner(System.in);
String name = scanner.nextLine();
for (int i = 0; i < booklist.usesize(); i++) {
if (name.equals(booklist.getBookName(i)) && booklist.getBook(i).IsBorrowed()){
System.out.println("该图书已借出");
return;
}
if (name.equals(booklist.getBookName(i))) {
booklist.getBook(i).setBorrowed_borrow();
System.out.println("借阅成功！");
return;
}
}
System.out.println("没有您要借阅的书籍");
}
}
测试
2.2.4.5 增加图书
先判断书架是否是满的
再判断是否存在同名书籍
增加后需要将 usespace++
需要一个 set 方法
package book;
public class BookList {
private final int defaultcapacity = 10;//默认容量
protected Book[] booklist = new Book[defaultcapacity];
private int usespace;//已存书本容量
public BookList() {
this.booklist[0] = new Book("三体", "刘慈欣", 18.88, "小说");
this.booklist[1] = new Book("西游记", "吴承恩", 17.77, "小说");
this.booklist[2] = new Book("红楼梦", "曹雪芹", 16.66, "小说");
usespace = 3;
}
public int usesize(){
// 存放书本数量
return this.usespace;
}
public int size(){
// 书架总容量
return this.booklist.length;
}
public void setUsespace(int usespace) {
//改变书架书的数量
this.usespace = usespace;
}
public void setBooklist(Book book){
// 增加书籍
this.booklist[usespace++] = book;
}
public String getBookName(int index){
// 返回对应位置的书名
return this.booklist[index].getName();
}
public Book getBook(int index){
// 返回对应位置的书
return this.booklist[index];
}
}
public class AddBehavior implements Behavior{
@Override
public void work() {
System.out.println("添加图书");
if (booklist.size() == booklist.usesize()) {
System.out.println("书架已满!");
return;
}//判断书架是否已满
Scanner scanner = new Scanner(System.in);
System.out.println("请输入您要添加的书籍名称：");
String name = scanner.nextLine();
for (int i = 0; i < booklist.usesize(); i++) {
// 判断是否存在同名书籍
if (name.equals(booklist.getBookName(i))) {
System.out.println("系统已收录该图书");
return;
}
}
System.out.println("请输入该书的作者");
String author = scanner.nextLine();
System.out.println("请输入该书的价格");
double price = scanner.nextDouble();
String type = scanner.nextLine();//接受回车键
System.out.println("请输入该书的类型");
type = scanner.nextLine();
Book book = new Book(name,author,price,type);
booklist.setBooklist(book);
System.out.println("新增图书成功！");
}
}
测试
2.2.4.6 删除图书
找到对应的图书
如果已经借出就不能删除
如果没有借出
将他所在空间置为 null
然后将他所在位置之后的图书向前移动
同样需要在 BookList 类中补充方法
package book;
public class BookList {
private final int defaultcapacity = 10;//默认容量
protected Book[] booklist = new Book[defaultcapacity];
private int usespace;//已存书本容量
public BookList() {
this.booklist[0] = new Book("三体", "刘慈欣", 18.88, "小说");
this.booklist[1] = new Book("西游记", "吴承恩", 17.77, "小说");
this.booklist[2] = new Book("红楼梦", "曹雪芹", 16.66, "小说");
usespace = 3;
}
public int usesize(){
// 存放书本数量
return this.usespace;
}
public int size(){
// 书架总容量
return this.booklist.length;
}
public void setUsespace(int usespace) {
//改变书架书的数量
this.usespace = usespace;
}
public void setBooklist(Book book){
// 增加书籍(放在尾部)
this.booklist[usespace++] = book;
}
public void setBooklist(Book book,int index){
// 增加书籍(指定位置)
this.booklist[index] = book;
}
public void removeBook(int index){
//删除对应下标位置的书
this.booklist[index] = null;
}
public String getBookName(int index){
// 返回对应位置的书名
return this.booklist[index].getName();
}
public Book getBook(int index){
// 返回对应位置的书
return this.booklist[index];
}
}
package behavior;
import java.util.Scanner;
public class RemoveBehavior implements Behavior {
@Override
public void work() {
System.out.println("删除图书！");
Scanner scanner = new Scanner(System.in);
System.out.println("请输入您要删除的书籍名称：");
String name = scanner.nextLine();
for (int i = 0; i < booklist.usesize(); i++) {
if (name.equals(booklist.getBookName(i)) && booklist.getBook(i).IsBorrowed()) {
// 已借出不能删除
System.out.println("该图书已借出");
return;
}
if (name.equals(booklist.getBookName(i)) && !booklist.getBook(i).IsBorrowed()) {
booklist.removeBook(i);//指定位置置空
for (int j = i; j < booklist.usesize() - 1; j++) {
//指定位置处的书向前移动
booklist.setBooklist(booklist.getBook(j + 1), j);
}
System.out.println("删除成功！");
int newspace = booklist.usesize();
booklist.setUsespace(--newspace);//删除后 书架中的存储的书的数量减少
return;
}
}
System.out.println("没有您要删除的书籍");
return;
}
}
测试
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