Lambda

Lambda表达式的语法

基本语法: (parameters) -> expression
或者：(parameters) ->{ statements; }

    @Test
    public void testLambda(){

        /**基础使用*/
        Runnable runnable = ()->System.out.println("runable" + System.currentTimeMillis());
        Thread thread = new Thread(runnable);
        thread.run();

        List<StringBuilder> list = new ArrayList<>();
        list.add(new StringBuilder("ab"));
        list.add(new StringBuilder("bc"));
        list.add(new StringBuilder("cd"));
        list.forEach((i)->i.append(1));
        list.forEach(System.out::println);

        System.out.println("________fen ge xian ___________");
        /**转换*/
        //no parameter and return
        Supplier<Integer> integerSupplier = () -> 5;
        System.out.println(integerSupplier.get());
        // one parameter and return
        Function<Integer, Integer> integerFunction = x -> 2*x ;
        System.out.println(integerFunction.apply(2));
        // two parameter and return
        BiFunction<Integer, Integer,Integer> integerIntegerBiFunction = (x, y)-> x-y;
        System.out.println(integerIntegerBiFunction.apply(2,2));

        BiFunction<Float, Float,Float> XXBiFunction = (x, y)-> x-y;

        BiFunction<Float, Float, Float> floatFloatBiFunction = (Float x, Float y)-> x-y;
        System.out.println(floatFloatBiFunction.apply(2f,2f));

        //one parameter and void
        Consumer<String> stringConsumer = (x)-> System.out.println(x);
        stringConsumer.accept("ni hao");

        System.out.println("________fen ge xian ___________");

        /**自己定义FunctionInterface*/
        //FunctionInterface   one parameter and void
        TestLambdaVoid lambdaFunctionInterface = ()->System.out.println("wo shi lambda function");
        lambdaFunctionInterface.testCall();

        //FunctionInterface   one parameter and void
        TestLambda testLambda = new TestInterface(1);
        System.out.println(testLambda.testCall(2));
        TestLambda testLambda1 = (i)->String.valueOf(i+1);
        System.out.println(testLambda1.testCall(2));

    }

    public class TestInterface implements TestLambda{

        public int id;

        public TestInterface(int i) {
            this.id = i;
        }

        @Override
        public String testCall(int i) {
            id = id+ i;
            return String.valueOf(id);
        }

    }

@FunctionalInterface
public interface TestLambda {

    String testCall(int i);

}

@FunctionalInterface
interface TestLambdaVoid {
    void testCall();
}