java8 lambda表达式 小例子

// Function<T, R> -T作为输入，返回的R作为输出 
        Function<String,String> function = (x) -> {System.out.print(x+": ");return "Function";};
        System.out.println(function.apply("hello world"));
        
        //Predicate<T> -T作为输入，返回的boolean值作为输出 
        Predicate<String> pre = (x) ->{System.out.print(x);return false;};
        System.out.println(": "+pre.test("hello World"));
        
        //Consumer<T> - T作为输入，执行某种动作但没有返回值 
        Consumer<String> con = (x) -> {System.out.println(x);};
        con.accept("hello world");
        
        //Supplier<T> - 没有任何输入，返回T 
        Supplier<String> supp = () -> {return "Supplier";};
        System.out.println(supp.get());
        
        //BinaryOperator<T> -两个T作为输入，返回一个T作为输出，对于“reduce”操作很有用 
        BinaryOperator<String> bina = (x,y) ->{System.out.print(x+" "+y);return "BinaryOperator";};
        System.out.println("  "+bina.apply("hello ","world"));

输出

hello world: Function
hello World: false
hello world
Supplier
hello  world  BinaryOperator