java.util.function
![1610803617648.png](/uploads/projects/shenguangyang@zmkork/2a460ab426b5847c2895d34cc50a6c51.png)
java内置核心四大函数式接口
![1610803617691.png](/uploads/projects/shenguangyang@zmkork/431d688b314c0294ce8c23bad9493591.png)
实例代码
//R apply(T t);函数型接口,一个参数,一个返回值
Function<String,Integer> function = t ->{return t.length();};
System.out.println(function.apply("abcd"));
//boolean test(T t);断定型接口,一个参数,返回boolean
Predicate<String> predicate = t->{return t.startsWith("a");};
System.out.println(predicate.test("a"));
// void accept(T t);消费型接口,一个参数,没有返回值
Consumer<String> consumer = t->{
System.out.println(t);
};
consumer.accept("javaXXXX");
//T get(); 供给型接口,无参数,有返回值
Supplier<String> supplier =()->{return UUID.randomUUID().toString();};
System.out.println(supplier.get());