构造器引用和数组引用的使用

* 一、构造器引用 * 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 * * 二、数组引用 * 可以把数组看做一个特殊的类，则写法与构造器引用一致。 * * * Created by 阿昌 public class ConstructorRefTest { //构造器引用 //Supplier中的T get() //Employee的空参构造器: Employee(); @Test public void test1(){ //原始写法 Supplier<Employee> sup0 = new Supplier<Employee>() { @Override public Employee get() { return new Employee(); } }; System.out.println(sup0.get()); System.out.println("==========================================");//分割线 //Lambda表达式写法 Supplier<Employee> sup1 = () -> new Employee(); System.out.println(sup1.get()); System.out.println("==========================================");//分割线 //构造器引用写法 Supplier<Employee> sup2 = Employee::new; System.out.println(sup2.get()); } //Function中的R apply(T t) @Test public void test2(){ //Lambda表达式写法 Function<Integer,Employee> fun1 = id -> new Employee(id); Employee employee = fun1.apply(1001); System.out.println(employee); System.out.println("==========================================");//分割线 //构造器引用写法 Function<Integer,Employee> fun2 = Employee::new; Employee employee1 = fun2.apply(1002); System.out.println(employee1); } //BiFunction中的R apply(T t,U u) @Test public void test3(){ //Lambda表达式写法 BiFunction<Integer,String,Employee> bif1 = (id,str) -> new Employee(id,str); Employee employee = bif1.apply(1001, "张薇"); System.out.println(employee); System.out.println("==========================================");//分割线 //构造器引用写法 BiFunction<Integer,String,Employee> bif2 = Employee::new; Employee employee1 = bif2.apply(1002, "刘芳"); System.out.println(employee1); } //数组引用 //Function中的R apply(T t) @Test public void test4(){ //Lambda表达式写法 Function<Integer,String[]> func1 = length -> new String[length]; String[] arr1 = func1.apply(8); System.out.println(Arrays.toString(arr1)); System.out.println("==========================================");//分割线 //数组引用的写法 Function<Integer,String[]> func2 = String[] :: new; String[] arr2 = func2.apply(5); System.out.println(Arrays.toString(arr2)); } }