How to write a class in Java

2 years ago
Liam
2 minutes

To create a Java class, follow these steps:

  1. To create a new Java file, the file name must be the same as the class name, with a .java file extension. For example, if you want to create a class called MyClass, you can create a file named MyClass.java.
  2. In a Java file, you define a class using the keyword “class” and provide a name for the class. For example, public class MyClass { }.
  3. Inside a class, you can define the class’s properties and methods. Properties are the class’s member variables, used to store the object’s state. Methods are the class’s member functions, used to define the class’s behavior.
  4. Attributes can control their visibility using access modifiers such as private, public, and protected. Methods can also control their visibility using access modifiers.
  5. Within the class, it is possible to define a constructor method. This method is used to create objects of the class and initialize their properties.
  6. Inside the class, you can define other methods to implement the functionality of the class.

Here is a simple example demonstrating how to write a Java class:

public class MyClass {
    // 属性
    private int myInt;

    // 构造方法
    public MyClass(int myInt) {
        this.myInt = myInt;
    }

    // 方法
    public void printMyInt() {
        System.out.println("My integer is: " + myInt);
    }

    public static void main(String[] args) {
        // 创建对象
        MyClass myObj = new MyClass(10);

        // 调用方法
        myObj.printMyInt();
    }
}

In the example above, a class named MyClass is created. The class has a private attribute called myInt, a public constructor, and a public method named printMyInt. In the main method, a MyClass object named myObj is created and the printMyInt method is called to print out the object’s attribute value.

I hope this helps you!

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