java - Method Overloading null parameter

Question

In my code, I have a method which has got to take 4 parameters. But in somewhere in the code i call this method with sometimes 2, sometimes 4 parameters. So when i call with 2 parameters, the last 2 parameters should go automaticly null.

For example:

public static void x(String one,String two,String three=null,String four=null){

//do something hear

}

x("one","two");
x("one","two","three","four");

When I call x("one","two") => I want that the three and four parameters automatticaly initialize to null.

How can i do that ? Thanks for helps.

Answer 1

class A{

   public void do(String a, String b, String c, String d){
        //do something
   }

   //Overload do method
   public void do(String a, String b){
        do(a,b,null,null);
   }
}

Answer 2

这也很有效，可以使用字符串数组作为参数或多个逗号分隔的字符串来调用。这样你就不必超载了。

public void myMethod(String ...strings)  {
    for (String string : strings) {
        //do something with the string
    }
}

您可以使用数组调用它：

myMethod(new String[]{"test1", "test2"})

或几个字符串：

myMethod("test1", "test2");
myMethod("test1", "test2", "test3", "test4");

Answer 3

最好的选择是让你的方法只使用 4 个参数，当你只需要传递 2 个参数时，将其他 2 个参数传递为 null。

例如 2 个参数传递：

    x(a,b,null,null);

对于 4 个参数传递：

    x(a,b,c,d);