lambda表达式基于函数式接口即可运用
COPY Function<String,String> function = str->{return str;};
System.out.println(function.apply("测试"));
特定:有一个输入参数,返回值只能是布尔值!
COPY Predicate<String> predicate = (str)->{return str.isEmpty(); };
System.out.println(predicate.test(""));
特点:只有输入,没有返回值
COPY Consumer<String> consumer = (str)->{System.out.println(str);};
consumer.accept("测试");
特定:只有返回值,没有参数
COPYSupplier supplier = ()->{ return ; };
System.out.println(supplier.get());