Enkapsulacija v Javi je proces ovijanja kode in podatkov skupaj v eno samo enoto , na primer kapsula, ki je mešanica več zdravil.

shilpa shetty

V Javi lahko ustvarimo popolnoma enkapsuliran razred tako, da vse podatkovne člane razreda naredimo zasebne. Zdaj lahko uporabimo metode setter in getter za nastavitev in pridobivanje podatkov v njem.

The Java Bean razred je primer popolnoma enkapsuliranega razreda.

Prednost enkapsulacije v Javi

Razred lahko naredite tako, da zagotovite samo metodo postavljalca ali pridobivanja samo za branje ali samo za pisanje . Z drugimi besedami, lahko preskočite metode getter ali setter.

Zagotavlja vam nadzor nad podatki . Recimo, da želite nastaviti vrednost ID-ja, ki mora biti samo večja od 100, lahko logiko zapišete znotraj metode nastavljalnika. Lahko napišete logiko, da ne shranjujete negativnih števil v metode nastavljalcev.

To je način za doseganje skrivanje podatkov v Javi, ker drugi razredi ne bodo mogli dostopati do podatkov prek članov zasebnih podatkov.

Enkapsulirani razred je enostaven za testiranje . Zato je bolje za testiranje enot.

Standardni IDE zagotavljajo možnost generiranja pridobivalnikov in nastavljalcev. Torej je preprosto in hitro ustvariti enkapsuliran razred v Javi.

Preprost primer enkapsulacije v Javi

Oglejmo si preprost primer enkapsulacije, ki ima samo eno polje s svojima metodama nastavitve in pridobivanja.

Datoteka: Student.java

 //A Java class which is a fully encapsulated class. //It has a private data member and getter and setter methods. package com.javatpoint; public class Student{ //private data member private String name; //getter method for name public String getName(){ return name; } //setter method for name public void setName(String name){ this.name=name } } 

Datoteka: Test.java

 //A Java class to test the encapsulated class. package com.javatpoint; class Test{ public static void main(String[] args){ //creating instance of the encapsulated class Student s=new Student(); //setting value in the name member s.setName('vijay'); //getting value of the name member System.out.println(s.getName()); } } 

 Compile By: javac -d . Test.java Run By: java com.javatpoint.Test 

Izhod:

 vijay 

Razred samo za branje

 //A Java class which has only getter methods. public class Student{ //private data member private String college='AKG'; //getter method for college public String getCollege(){ return college; } } 

Zdaj ne morete spremeniti vrednosti člana podatkov o fakulteti, ki je 'AKG'.

 s.setCollege('KITE');//will render compile time error 

Razred samo za pisanje

 //A Java class which has only setter methods. public class Student{ //private data member private String college; //getter method for college public void setCollege(String college){ this.college=college; } } 

Zdaj ne morete pridobiti vrednosti kolegija, spremenite lahko le vrednost podatkov o članu fakultete.

 System.out.println(s.getCollege());//Compile Time Error, because there is no such method System.out.println(s.college);//Compile Time Error, because the college data member is private. //So, it can't be accessed from outside the class 

Še en primer enkapsulacije v Javi

Oglejmo si še en primer enkapsulacije, ki ima samo štiri polja z metodama nastavitve in pridobivanja.

Datoteka: Account.java

mysql pokaži uporabnike

 //A Account class which is a fully encapsulated class. //It has a private data member and getter and setter methods. class Account { //private data members private long acc_no; private String name,email; private float amount; //public getter and setter methods public long getAcc_no() { return acc_no; } public void setAcc_no(long acc_no) { this.acc_no = acc_no; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public float getAmount() { return amount; } public void setAmount(float amount) { this.amount = amount; } } 

Datoteka: TestAccount.java

 //A Java class to test the encapsulated class Account. public class TestEncapsulation { public static void main(String[] args) { //creating instance of Account class Account acc=new Account(); //setting values through setter methods acc.setAcc_no(7560504000L); acc.setName('Sonoo Jaiswal'); acc.setEmail('[email protected]'); acc.setAmount(500000f); //getting values through getter methods System.out.println(acc.getAcc_no()+' '+acc.getName()+' '+acc.getEmail()+' '+acc.getAmount()); } } 

Izhod:

 7560504000 Sonoo Jaiswal [email protected] 500000.0