lambda表达式

Posted 2021-03-20 liuyi13535496566

/**
 * 1    LambdaExpress写法：拷贝中括号，写死右箭头，落地大括号
 * 2    LambdaExpress对接口的要求，接口里面的抽象方法，有且仅有一个
 * 3    函数式接口才能使用Lambda写法,
 * 4    新注解@FunctionalInterface
 * 5    default默认实现
 * 6    静态实现
 */

@FunctionalInterface
interface Foo
{

　　//public void sayHello();

    public int add(int x, int y);

    default int multi(int x, int y)
    {
        return x * y;
    }

    public static int div(int x, int y)
    {
        return x / y;
    }
    public static int div2(int x, int y)
    {
        return x / y;
    }

}

public class LambdaExpressDemo
{
    public static void main(String[] args)
    {
        /*Foo foo = new Foo()
        {
            @Override
            public void sayHello()
            {
                System.out.println("********hello java180228");
            }

        };
        foo.sayHello();*/

        //Foo foo = () -> {System.out.println("********hello ");};
        //foo.sayHello();

        Foo foo = (x,y) -> {
            System.out.println("*******come in add()");
            return x + y;
        };

        System.out.println(foo.add(3,15));
        
    }
}