The specific operation of the step of the package

Outline

Object-oriented programming language is a simulation of the objective world, the objective world, member variables are hidden inside the object, the outside world can not directly manipulate and modify. Package may be considered as a protective barrier against the class codes and other types of data are accessed randomly. To access this kind of data, you must specify the way through. Appropriate encapsulation makes the code easier to understand and maintain, and enhance the security of the code.

Principles package

The property is hidden, if the need to access a property, providing public access to its methods.

 

Step package

 

1, using the private key to modify the member variables.

 

2, member variables need to access, provide a common access method, which is defined corresponding getXxx method, setXxx method.

 

Package key operation --private

 

private meanings

 

 1, Private is a privilege modifier, on behalf of least privilege. 

 

 2, can be modified member variables and member methods to achieve the purpose of the hidden attribute

 3, the member variables and member methods after private modification, only be accessed in this category

 

private use format

 

 

private data type variable name;

 

Why use private modification?

Because not to expose properties to others

 

this keyword

this meaning

this refers to the current object where the class representative (address value) that their object references.

Remember : method is called which object, this method represents that object. That is who to call, who this represents.

 

 

Construction method

When an object is created when the method is used to initialize the object constructor, the object member variable to the initial value assigned.

Role: initialize the object, the object is assigned to the member variables initial

Definition Format constructor

 

 

 

 Specific examples of the package

 

public  class the Person {
     // define the member variables 
    Private String name; // Name 
    Private  int Age; // Age 
    Private  char gendar; // Gender 

    // define the members of method 

    // There arg constructor 
    public the Person () { 

    } 
    // No arg constructor 
    public the Person (String name, int Age, char gendar) {
         the this .name = name;
         the this .age = Age;
         the this .gendar = gendar; 
    }
    //get和set方法
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public char getGendar() {
        return gendar;
    }

    public void setGendar(char gendar) {
        the this .gendar = gendar; 
    } 

    / ** 
     * Study Method 
     * 
     * / 
    public  void Study () { 
        System.out.println ( "good school study, every day" ); 
    } 

    / ** 
     * SLEEP (); sleep 
     * / 
    public  void sLEEP () { 
        System.out.println ( "study day, can sleep" ); 
    } 
}