构造器引用与数组引用

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1.构造器引用格式：

类名::new

2.构造器引用使用要求：

和方法引用类似，函数式接口的抽象方法的形参列表和构造器的形参列表一致。抽象方法的返回值类型即为构造器所属的类的类型

3.构造器引用举例：

//Supplier中的T get()
//Employee的空参构造器：Employee()
@Test
public void test1(){

   Supplier<Employee> sup = new Supplier<Employee>() {
	   @Override
	   public Employee get() {
		   return new Employee();
	   }
   };
   System.out.println("*******************");

   Supplier<Employee>  sup1 = () -> new Employee();
   System.out.println(sup1.get());

   System.out.println("*******************");

   Supplier<Employee>  sup2 = Employee :: new;
   System.out.println(sup2.get());
}

//Function中的R apply(T t)
@Test
public void test2(){
   Function<Integer,Employee> func1 = id -> new Employee(id);
   Employee employee = func1.apply(1001);
   System.out.println(employee);

   System.out.println("*******************");

   Function<Integer,Employee> func2 = Employee :: new;
   Employee employee1 = func2.apply(1002);
   System.out.println(employee1);
}

//BiFunction中的R apply(T t,U u)
@Test
public void test3(){
   BiFunction<Integer,String,Employee> func1 = (id,name) -> new Employee(id,name);
   System.out.println(func1.apply(1001,"Tom"));

   System.out.println("*******************");

   BiFunction<Integer,String,Employee> func2 = Employee :: new;
   System.out.println(func2.apply(1002,"Tom"));
}

4.数组引用格式：

数组类型[] :: new

5.数组引用举例：

//Function中的R apply(T t)
@Test
public void test4(){
    Function<Integer,String[]> func1 = length -> new String[length];
    String[] arr1 = func1.apply(5);
    System.out.println(Arrays.toString(arr1));

    System.out.println("*******************");

    Function<Integer,String[]> func2 = String[] :: new;
    String[] arr2 = func2.apply(10);
    System.out.println(Arrays.toString(arr2));
}