Java8之Lambda表达式

public
 class LamdaTest {
    @Test
    public void test1() {
        Runnable r1 = new Runnable() {
            @Override
            public void run() {
                System.out.println("hello");
            }
        };
        r1.run();
        System.out.println("===============");

        Runnable r2 = () ->System.out.println("hello lambda");
        r2.run();
    }

    @Test
    public void test2(){
        Consumer consumer = x -> System.out.println("这是test2"+x);
        consumer.accept(1);
    }

    @Test
    public void test3(){
        Comparator comparator = (x,y) -> x + y;
        System.out.println(comparator.compare(1,2));;
    }
}

public class LamdaTest01 {
    //Consumer消费型接口
    public void happy(double money, Consumer consumer){
        consumer.accept(money);
    }

    @Test
    public void test01(){
        happy(10000, m -> System.out.println("你们刚哥喜欢消费，每次消费"+m+"元"));
    }

    //Supplier供给型接口
//    需求：产生指定数量整数，并存入到集合中
    public List getNumList(int num, Supplier supplier){
        List list = new ArrayList<>();
        for (int i = 0; i < num; i++){
            list.add(supplier.get());
        }
        return list;
    }

    @Test
    public void test02(){
        List numList = getNumList(5, () -> (int) (Math.random() * 100));
        for (Integer numm : numList) {
            System.out.println(numm);
        }
    }

    //函数型接口
    public Integer getStrLength(String str, Function function){
        return  function.apply(str);
    }

    @Test
    public void test03(){
        System.out.println(getStrLength("你好啊",x -> x.length()));
    }

//    断言型接口
//    需求：将满足条件的字符串放入到集合中去
    public List filterStr(List list, Predicate predicate){
        List list1 = new ArrayList<>();
        for (String str:
             list) {
            if (predicate.test(str)){
                list1.add(str);
            }
        }
        return list1;
    }

    @Test
    public void test04(){
        List list = Arrays.asList("张三","Hello world","李庆霖","王五","lambda","嗯哼嗯哼蹦擦擦");
        List strings = filterStr(list, x -> x.length() >= 7);
        for (String str:
             strings) {
            System.out.println(str);
        }
    }
}