What is encapsulation java
In the object-oriented programming method, encapsulation (English: Encapsulation) refers to a method of partially packaging and hiding the implementation details of an abstract functional interface.
Encapsulation can be thought of as a protective barrier that prevents the code and data of the class from being randomly accessed by code defined by the external class.
To access the code and data of this class, you must pass strict interface control.
The main function of encapsulation is that we can modify our own implementation code without modifying the program fragments that call our code.
Proper encapsulation can make the program code easier to understand and maintain, and also enhance the security of the program code. (Recommended tutorial: java tutorial)
Advantages of encapsulation
1. Good encapsulation can reduce coupling.
2. The structure inside the class can be modified freely.
3. Member variables can be controlled more precisely.
4. Hide information and implement details.
Java encapsulation, to put it bluntly, is to put some common implementation logic into a box (class), and the entrance and exit are on this box. If you want to use it, just use this box, connect it to the entrance and exit, and then you can use it. If you don't use it, you can just throw it away. It will have no impact on your code.
For programmers, the purpose of using encapsulation is:
1. Being lazy and working hard once will save you a lot of code later, which enhances code reuse. Nature
2. Simplify the code and make it easier to understand
3. Hide the core implementation logic code, simplify the external logic, and prevent others from modifying it. This is what jars do
4. One-to-one, one function only serves this function; avoid using hair ropes together, resulting in a mess in the end
Example:
public class EncapTest{
private String name;
private String idNum;
private int age;
public int getAge(){
return age;
}
public String getName(){
return name;
}
public String getIdNum(){
return idNum;
}
public void setAge( int newAge){
age = newAge;
}
public void setName(String newName){
name = newName;
}
public void setIdNum( String newId){
idNum = newId;
}
}In the above example, the public method is the entrance for the external class to access the member variables of the class.
Normally, these methods are called getter and setter methods.
Therefore, any class that wants to access private member variables in the class must go through these getter and setter methods.
The following example illustrates how the variables of the EncapTest class are accessed:
public class RunEncap{
public static void main(String args[]){
EncapTest encap = new EncapTest();
encap.setName("James");
encap.setAge(20);
encap.setIdNum("12343ms");
System.out.print("Name : " + encap.getName()+ " Age : "+ encap.getAge());
}
}The above code is compiled and run and the results are as follows:
Name : James Age : 2
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