爪哇 - 做java的有一些像C＃的结构构造自动 [英] Java - Do java have something like C#'s struct automatic constructor

问题描述

我已经使用C＃很长一段时间，现在我需要做Java的东西。

I've been using C# for a long time and now I need to do something in Java.

有什么样的C＃结构自动构造在java中？

Is there something like C#'s struct automatic constructor in java ?

我的意思是
在C＃

What I mean is In C#

struct MyStruct
{
    public int i;
}
class Program
{
    void SomeMethod()
    {
        MyStruct mStruct; // Automatic constructor was invoked; This line is same as MyStruct mStruct = new MyStruct();
        mStruct.i = 5;   // mStruct is not null and can i can be assigned
    }
}

是否有可能强制Java在声明中使用默认的构造函数

Is it possible to force java to use default constructor on declaration ?

推荐答案

没有？ - Java不支持自定义值类型的所有和构造函数总是明确要求。

No - Java doesn't support custom value types at all, and constructors are always explicitly called.

不过，你的C＃的理解是不正确反正。从你的原帖：

However, your understanding of C# is incorrect anyway. From your original post:

// Automatic constructor was invoked
// This line is same as MyStruct mStruct = new MyStruct();
MyStruct mStruct; 

这是不正确的。你可以的写下来到 mStruct.i 这里没有任何明确的初始化，但你不能的阅读的，除非编译器知道一切都已经分配一个值：

That's not true. You can write to mStruct.i without any explicit initialization here, but you can't read from it unless the compiler knows everything has been assigned a value:

MyStruct x1; 
Console.WriteLine(x1.i); // Error: CS0170: Use of possibly unassigned field 'i'

MyStruct x1 = new MyStruct();
Console.WriteLine(x1.i); // No error

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