//java8的4大核心函数式接口//1.Consumer<T>:消费性接口//需求：public void happy(double money, Consumer<Double> consumer){    consumer.accept(money);}@Testpublic void test(){    happy(1000,(e)-> System.out.println("happy消费了"+ e +"元"));}//2.Supplier<T> 供给型接口//T get();//需求：产生一定数量整数，并放进集合中public List<Integer> getList(int size, Supplier<Integer> supplier){    List<Integer> list = new ArrayList<>();    for (int i = 0; i < size; i++) {        Integer num = supplier.get();        list.add(num);    }    return list;}

@Testpublic void test2(){    List<Integer> list = getList(10,()->(int)(Math.random()*100));    for (Integer num :            list) {        System.out.println(num);    }}

//3.函数型接口//Function<T,R>//R apply<T t>//需求：去除首尾空格public String strHandler(String str, Function<String,String> fun){    return fun.apply(str);}@Testpublic void test3(){    String strTrim = strHandler("\t\t\txsjifcdsnkjfhs   ",(e)->e.trim());    System.out.println(strTrim);}//4.Predicate 断言型接口//boolean test(T t)//将满足条件的字符串放进集合public List<String> getNewList(List<String> list , Predicate<String> pre){    List<String> newList = new ArrayList<>();    for (String str :            list) {        if(pre.test(str)){            newList.add(str);        }

    }    return newList;}@Testpublic void test4(){    List<String> list = java.util.Arrays.asList("adsj","xjsai","sdjasio","ws");    List<String> li = getNewList(list,(s)->s.length()>3);    for (String str :         li) {        System.out.println(str);    }

}