如何从静态块创建对象? [英] How can an object be created from a static block?

问题描述

在默认包中考虑两个类:

Consider two classes in a default package :

    class Trial {
        int a;
        int b;

        public static void main (String [] args){
            System.out.println("test base");

        }


    }

    public class TrialExe {
        int a;
        int b;

        public static void main (String [] args){
            Trial t = new Trial();
            System.out.println("test exe");
        }


    }       

编译TrialExe:javac TrialExe

Compiling TrialExe: javac TrialExe

如何编译?考虑到Trial对象是从静态块创建的，要创建对象，需要Trial的构造函数，但据我所知，我们无法从静态方法访问非静态方法，并且构造函数是非静态的.

How can this compile?. Considering that the Trial object is created from a static block, to create an object the constructor of Trial is required, but as far as I know we cannot access a non static method from a static method and the constructor is non static.

推荐答案

静态方法不能调用非静态方法或字段.没错.

A static method cannot call a non-static method or field. That is correct.

但是构造函数很特殊.您可以从静态方法中构造一个新对象，然后可以调用该对象的方法，即使它们不是静态的，并且即使该对象是同一类的实例也是如此.

But constructors are special. You can construct a new object from within a static method and then you can call that object's methods, even if they are not static and even if that object is an instance of the same class.

这样想:

• 静态方法属于该类.只有其中之一，不需要构造.
• 实例(非静态)方法属于对象实例.

因此，由于没有封装实例，因此无法从静态方法调用实例方法.但是，静态方法可以创建一个对象，然后调用该实例的方法.

Because of this, you cannot call an instance method from a static method because there is no encapsulating instance. However, a static method can create an object and then call that instance's methods.

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