1.方法引用

物件：：方法 引用型別一樣
public void test5(){
    Consumer<String> con = System.out::println;
    con.accept("消費一下");
    Supplier<String> s1 = new Supplier<String>() {
        @Override
        public String get() {
            return "得到";
        }
    };
    Person person = new Person(12, "jack");
    Supplier
 
<String> s2 = ()->person.getName();
    Supplier<String> s3 = person::getName;
    System.out.println(s2.get());
    System.out.println(s3.get());
}

物件：：方法 引用型別不同，但是一個是呼叫者
public void test6(){
    Comparator<Integer> com = (o1,o2)->Integer.compare(o1,o2);
    System.out.println(com.compare(
 
1, 2));
    Comparator<Integer> com2 = Integer::compare;
    System.out.println(com2.compare(1, 2));
    Function<Double,Long> f1 = Math::round;
    System.out.println(f1.apply(10.2));
    System.out.println(f1.apply(10.6));
}
類：：方法
public void test7(){
    Comparator<String> com = (s1,s2)->s1.compareTo(s2);
    System.out.println(com.compare(
 
"abc", "ab"));
    Comparator<String> com2 = String::compareTo;
    System.out.println(com2.compare("abc", "ab"));
    Person person = new Person(12, "jack");
    Function<Person,String > f1 = p->p.getName();
    System.out.println(f1.apply(person));
    Function<Person,String > f2 = Person::getName;
    System.out.println(f2.apply(person));
}