Java在C＃中初始化类，就像在C＃中一样

Question

I'm quite base in Java because I'm full time C# developer but i need make some private project in Android.

In C# i can do something like this :

public class Test
{
    public string A {get;set;}
    public OtherClass B {get;set;}
}

public OtherClass ()
{
    string Some {get;set;}
    string Again {get;set;}
}

Now when I want to use class test i can do code like:

var test = new Test
{
    A = "test",
    B = new OtherClass
    {
        Some = "Some",
        Again = "Again"
    }
};

Thank to this now i have initialized test in clear way.

When i want do this in Java i must make code like :

public class Test
{
    private string A;
    public string GetA()
    {
        return A;
    }
    public void SetA(string a)
    {
        A = a;
    }

    privte  OtherClass B;
    public OtherClass GetB()
    {
        return B;
    }
    public void SetB(OtherClass b)
    {
        B = b;
    }
}



public class OtherClass
{
    private string Some;
    public string GetSome()
    {
        return Some;
    }
    public void SetSome(string some)
    {
        Some = some;
    }

    privte  string Again;
    public string GetAgain()
    {
        return Again;
    }
    public void SetAgain(string again)
    {
        Again = again;
    }
}

I know that Java must have Seter and Geter to field and i'm ok with this but now if i want to use Test object in way like i use it in C# i must do something like :

OtherClass otherClass = new OtherClass();
otherClass.SetSome("Some");
otherClass.SetAnothier("Another");
Test test = new Test();
test.SetA("A")
test.SetB(otherClass);

IMO this is not nice and clear declaration. I know that i can add constructor like :

public Test(string a, otherClass b)
{
    A = a;
    B = b;
}

and

public OtherClass(string some,string another)
{
     Some = some;
     Another = another;
}

And use it like :

Test test = new Test("Test",new OtherClass("some","Another"));

But when i have more complicated classes ( eg with 200 field ( yes i have that )) the constructor will be very long and it will hard to read it.

So can I initialize class in Java in other way that this I show you ?

Thank

Answer 1

You can actually use object initializers in java also, however they are called double brace initializers . Example:

Test test = new Test()
{{
    SetA("test");
    SetB(new OtherClass()
    {{
        SetSome("Some");
        SetAgain("Again");
    }});
}};

However you should probably not use this since it has some weird/unexpected side effects. This example produces an AnonymousInnerClass for Test and OtherClass . You can read more about double brace initializers here .

If you have more parameters than you wish to pass down your constructor you could use the builder pattern as suggested by this answer .