What is the use of java's parameterized constructor?

Parameterized construction in Java is a type of construction method, and the function of the construction method is to call the constructor to complete the initialization of the object when new an object. In order to initialize member properties, but not to initialize the object, initialize the object. This is achieved through the new keyword.

#If you want to understand the use of parameterized construction, you must first know the use of constructor methods, because parameterized construction is a type of construction method.

The function of the constructor (constructor):

When new an object, the constructor is called to complete the initialization of the object. In order to initialize the member properties, rather than initializing the object , the initialized object is implemented through the new keyword.

Initialize the object by calling the constructor method with new, and check the constructor according to the parameter signature during compilation, which is called static binding and compilation polymorphism (parameter signature: type of parameter, number of parameters and parameter order)

Creating a subclass object will call the parent class constructor but will not create the parent class object. It will just call the parent class constructor to initialize the parent class member properties;

The parameterized constructor is used to perform the function of the constructor, for example:

 class Person{
    int age;
    //有参构造方法
    public Person (int a){
        age=a;
    }
    public void speak(){
        System.out.println("我今年"+age+"岁");
    }
}

public class Test02{
    public static void main (String [] args){
        Person p=new Person (20);//实例化同时赋值
        p.speak();
    }
}

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