Implementation of a small book system

On the implementation of a small book system

This is about the implementation of a Book System , First, let's look at its basic functions

First , This book system can distinguish you from a librarian , Or an ordinary user

In addition, depending on the choice , We can choose different functions , Select the panel we get from the manager

Select the panel we get from the students

First, let's look at its basic functions , For example, we show books :>

Or look for books

Next , We implement it step by step through code :>

First , Since it is a Book System , Then you must have books ？, Books have information such as names and authors , So we can create a Book Class , To store our information .

Book class

Here we state 5 Member variables , It's our name,author,type,price,isBorrowed, Explain the name of a Book , author , type , Price , Whether it has been lent out , Here, our access qualification modifier adopts private, In order to achieve a packaging effect .

Besides , We also need to provide a construction method , To initialize the book .

Here, in our construction method , Without our isBorrowed member , Because member variables have a default value when they are not initialized ,boolean When members of type are not initialized, the default value is false, We can understand it as not lending .

Since the member variable is private modification , We should provide... Accordingly get and set Method , To access these member variables

There's nothing to say here ,( If you want to type it quickly, you can use idea Shortcut keys )

There is another step ！, That's rewriting our toString Method , So that we can print the books later :

BookList class

Now that there are books , Should there be a shelf for our books ？ This is the time , We created a BookList class , To store my books , At the same time, get the information of each of our books

stay BookList In it, we define a Book An array of types bookList, Used to store every book we have . There is also a record of how many books are stored in the current array usedSized. We also use private To modify , To achieve the effect of packaging :>

Besides , We also provide a parameter free construction method , First pair bookList and usedSized To initialize .

Since arrays and usedSized By private modification , We should also provide get and set Method .

Here we're talking about arrays bookList Provided get and set Method , For a specific book in the array , Therefore, we are operating in the array , Like the second setPos, We have two parameters book and pos , book It's the book we want to keep , pos Is the subscript of the book we want to store .

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A series of operations on the bookshelf

Now that there are books and shelves , The next step is to carry out a series of operations on the bookshelf , We put these operations in a package .

then , We divide the operations we need into various classes , For example, our operation of adding books , We can define it as a AddOperation class , For example, our book search operation , We can define it as a FindOperation class , We follow this line of thinking , Step by step .

ad locum , We have defined 7 Classes , increase , Borrow , Delete books and so on , Now let's look at the contents of its class ( With our AddOperation For example ）

Here we write a work Method ( We haven't realized the specific content in it yet ), adopt work Methods let's add a Book , Then other operations , For example, our FindOperation, ExitOperation Operation, etc. , You can also pass a work Method to implement , In this case , We can define an interface , To regulate work The behavior in .

In this case , All operations can be used to implement this interface .

Take an example of one of these classes :>

User class

Besides , With our operation class , Next, our object should be our user object ？ Users are divided into administrators and students , But from another point of view, they are also users , therefore , Here we will User Set as parent class , Put our managers -AdminUser, Student -NormalUser For its subclass , therefore , We can initially achieve ;

User class :>

Normal class

AdminUser class :>

In this way, we have preliminarily implemented such a user class .

MainClass

Next is the implementation of our main function , Since you want to enter a Book System , Then we must log in first, right ？, So let's first write a login Method

there login function , We choose the way , To identify you , Return an administrator or student object at the same time , Because they are User class , In fact, there is an upward transformation here .

Now that a subclass object is returned , We use it User Type of variable to receive . We want to , Should I print it after I accept it The corresponding menu ？, therefore , We can do it in User Add one to the class menu function , Let subclasses override it , In this case , You can go through user Call the corresponding menu ！

Here we write a menu function , But we don't want it in User Class specifies its contents , therefore , We can set it as an abstract method , In this case ,User Class also becomes an abstract class :>

since User It becomes an abstract class , that AdminUser Classes and Normal Class to override the abstract method of the parent class :

AdminUser

NormalUser

In this case , We User Type of user quote , After referencing the subclass object , You can call the corresponding menu Method .

In this case , You can display the corresponding menu , But here it is , We're a little short Step , That's it , To enter the corresponding action . therefore , We still need to menu Make some changes in the function :>

We are going to menu The return value of the function is changed to int, In this way, these operations can be received

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Now that the choice has been made , So should we consider who called the method corresponding to the administrator or the student ？ The words here , There is an operation , That is , We are in our User Define an interface array in an abstract class .

But here , We did not specify the specified size of the array , This is because it is used to store our operations , The operation of the administrator is different from that of the students , therefore , We need to be in Normal Classes and AdminUser Class to initialize the array accordingly

Normal class

AdminUser class

In this way, we get the corresponding method , The next step is to consider Who called it ？, There is also an operation here , That is to create a method , To call it , Next, let's look at an example :>

** Here we write a doOperaiton Method , It can ensure that who calls the method at the same time , You can also know exactly which method to call .** Next , We are right. MainClass Class :>

In this case , Our main framework has been written , What needs to be done next , That is to concretize our operation of bookshelves .

DisplayOperation

First , We will concretize the operation of the display book :.

Here, we first get the number of elements in the current array , And through our getPos( Get the books on the current shelf ), To print , Let's first look at the effect :>

So you ok 了 .

ExitOperation

First of all, let's recycle the resources here through the empty bookshelf , Then pass System.exit(), We pass it into a 0, It means that the program exits normally .

DelOperation

Before you get a specific deletion method , Let's start with an example :>

such , We have completed our deletion operation , Next, let's look at the specific code :>

Here we first enter the name of the book , To match the names in the bookshelf , then :>

Here we go through equals Method , Compare the names in the bookshelves one by one , So if you find it , We can do the... In our example , The next data replaces the previous data . Next, let's look at the effect :>

Deleted successfully ！

FindOperation

Then there is a little copy and paste , Paste us DelOperation Operation of methods in class :>

If we find the book we want to borrow , We put its member variables isBorrowed Set as true that will do , Let's see the effect :>

Loan success ！

ReturnOperation

The operation of returning books , It can be said that the operation is basically the same as that of borrowing books , It's just that we need to put the member variable isBorrowed Set as false that will do

Next, let's look at the effect :>

Successful return ！

FindOperation

Or copy and paste for a while :>

Next, let's look at the effect :>

Successfully found the name of the book .

In this case , Our book system is complete . Post my gitee home page , The following is the source code of the book system .

Book system