Jjava8 Lambda 神操作

Posted 2021-01-25 成长

  1 public class Lambda {
  2 
  3     @FunctionalInterface
  4     public interface AddInter {
  5         void add(int x, long y);
  6     }
  7 
  8     public interface AddInterTow extends AddInter {
  9         void add(int x, long y);
 10     }
 11 
 12     ///Predicate 传入apple类型的参数
 13     private static List<Apple> findApple1(List<Apple> appleList, Predicate<Apple> applePredicate) {
 14         ArrayList<Apple> newArrayList = Lists.newArrayList();
 15         for (Apple apple : appleList) {
 16             if (applePredicate.test(apple)) {
 17                 newArrayList.add(apple);
 18             }
 19         }
 20         return newArrayList;
 21     }
 22 
 23     ///Predicate 传入Long类型的参数 一个参数调用括号可以省略
 24     private static List<Apple> findApple2(List<Apple> appleList, Predicate<Long> applePredicate) {
 25         ArrayList<Apple> newArrayList = Lists.newArrayList();
 26         for (Apple apple : appleList) {
 27             if (applePredicate.test(apple.getWeight())) {
 28                 newArrayList.add(apple);
 29             }
 30         }
 31         return newArrayList;
 32     }
 33 
 34     ///两个参数的
 35     private static List<Apple> findApple3(List<Apple> appleList, BiPredicate<String, Long> applePredicate) {
 36         ArrayList<Apple> newArrayList = Lists.newArrayList();
 37         for (Apple apple : appleList) {
 38             if (applePredicate.test(apple.getColor(), apple.getWeight())) {
 39                 newArrayList.add(apple);
 40             }
 41         }
 42         return newArrayList;
 43     }
 44 
 45     ///一个参数的Consumer,accept方法没有返回值 具体干什么你来定
 46     private static void findApple4(List<Apple> appleList, Consumer<Apple> appleConsumer) {
 47         for (Apple apple : appleList) {
 48             appleConsumer.accept(apple);
 49         }
 50     }
 51     ///两个参数的
 52     private static void findApple5(String d,List<Apple> appleList, BiConsumer<Apple,String> appleConsumer) {
 53         for (Apple apple : appleList) {
 54             appleConsumer.accept(apple,d);
 55         }
 56     }
 57     private static String findApple6(Apple apple, Function<Apple,String> stringFunction) {
 58        return  stringFunction.apply(apple);
 59     }
 60 
 61     public static void main(String[] args) {
 62         ArrayList<Apple> list = Lists.newArrayList(new Apple("gree", 150L), new Apple("red", 200L), new Apple("blue", 300L));
 63         ///Predicate一个参数 || BiPredicate两个参数 || IntPredicate int参数的
 64         List<Apple> apple1 = findApple1(list, (apple) -> apple.getColor().equals("red"));
 65         System.out.println(JSON.toJSONString(apple1));
 66         List<Apple> apple2 = findApple2(list, num -> num > 150L);
 67         System.out.println(JSON.toJSONString(apple2));
 68         List<Apple> apple3 = findApple3(list, (a, b) -> a.equals("red") && b >= 200);
 69         System.out.println(apple3);
 70         System.out.println("==========================================>");
 71 
 72         ///Consumer 一个参数的
 73         findApple4(list, a -> System.out.println("{"+a.getColor()+":"+a.getWeight()+"}"));
 74         findApple5("consumer",list,(a,b)-> System.out.println(a.getColor()+":"+a.getWeight()+":"+b));
 75         System.out.println("=======================================>");
 76         ///function 传入一个值 返回一个值
 77         String apple6 = findApple6(new Apple("apple", 3000L), (x) -> x.toString());
 78         System.out.println(apple6);
 79 
 80         IntFunction<Double> apple7 = i->i*20.0d;
 81         System.out.println(apple7.apply(20));
 82         //Predicate || Function ||Supplier  || Consumer 常用的几个类
 83 
 84         System.out.println("===================================>推导==================");
 85         Consumer<String> consumerString = (s -> System.out.println(s));
 86         consumer(consumerString,"坚持");
 87         consumer(s-> System.out.println(s),"hellword consunmer");
 88         consumer(System.out::println,"system.out.pring");
 89 
 90         Integer aaa = Integer.parseInt("12345");
 91 
 92 
 93         SFunction<String, Integer> stringIntegerSFunction = Integer::parseInt;
 94         Integer integer = stringIntegerSFunction.apply("1234");
 95         System.out.println(integer);
 96 
 97 
 98         BiFunction<String,Long,Apple> biFunction = Apple::new;
 99         Apple biapple = biFunction.apply("biapple", 1000L);
100         System.out.println(biapple);
101     }
102 
103     public static <T> void  consumer(Consumer<T> consumer,T t){
104         consumer.accept(t);
105         consumer.accept(t);
106     }
107     public static void LambdaRun() {
108         SFunction<String, Object> stringObjectSFunction = (String s) -> s.length();
109         System.out.println(stringObjectSFunction.apply("大傻大傻大傻大傻"));
110 
111         Predicate<Apple> applePredicate = (apple -> apple.getColor().equals("red1"));
112         System.out.println(applePredicate.test(new Apple("red", 123L)));
113 
114         Supplier<Apple> appleSupplier = Apple::new;
115         System.out.println(appleSupplier.get());
116 
117         Runnable run = new Runnable() {
118             @Override
119             public void run() {
120                 System.out.println("hello word");
121             }
122         };
123         Runnable runnable = () -> System.out.println("hello word");
124         startRunnable(runnable);
125         startRunnable(run);
126         startRunnable(() -> System.out.println("hello"));
127     }
128 
129     public static void startRunnable(Runnable runnable) {
130         runnable.run();
131     }
132 }