Java＞函数式接口的使用Consumer、Function、Predicate、Supplier

Consumer;
Function;
Predicate;
Supplier;
.

import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;


public class lambdaDome {
    
    
    public static void main(String[] args) {
    
    
        // Lambda supplier method 1
        // supplier 生产型接口，接受什么值，返回什么值
        Integer integer = method_01_Supplier(() -> 100);
        System.out.println("Lambda 1 Return value is : " + integer);

        // method Consumer method 1
        // Consumer 消费型接口，消费传入的值
        String str_num = "666";
        method_01_Consumer(str_num, s -> System.out.println("Lambda 1 print value is :" + s));

        // method Consumer method 2
        
        String[] array_str = {
    
    "yh1,18", "yh2,19", "yh3,20"};
        // print string : name and age
        // 打印字符串，分别打印name字段和age字段
        method_02_Consumer(array_str, s -> System.out.print("Name is : " + s.split(",")[0]),
                s -> System.out.print("\tAge is : " + s.split(",")[1] + "\n"));

        // method Predicted method 1 test method
        // 判断大于10的数字，并返回结果
        System.out.println("> 10 :" + method_Predicted_01(integer, i -> i > 10));

        // method Predicted method 2 and method -> &&
        // 判断大于10的，模2等于0的，并返回结果
        System.out.println("> 10 and '%2 == 0' : " + method_Predicted_02(integer, i -> i > 10, j -> j % 2 == 0));

        // method Predicted method 3 and method -> ||
        // 判断大于10的，模3等于0的，并返回结果
        System.out.println("> 10 and '%3 == 0' : " + method_Predicted_03(integer, i -> i > 10, j -> j % 3 == 0));

        // method Predicted method 3 and method -> !
        // 模3等于0的，对结果取反
        System.out.println("> !result : " + method_Predicted_04(integer, k -> k % 3 == 0));

        // 转换String to Integer
        method_Function_apply(str_num,i-> Integer.parseInt(str_num));

        // String to Integer to String
        method_Function_andThen(str_num , (s)->Integer.parseInt(s),(s)->s+"");

        String[] strings = {
    
    "迪丽热巴,23", "古力娜扎,27", "马尔扎哈,18", "赵丽颖,18", "杨幂,16",};
        Integer sum = method_Function_andThen1(strings,(s)-> Integer.parseInt(s.split(",")[1]),(i)-> i + 100);
        System.out.println(sum);
    }

    // @FunctionalInterface Supplier
    // Supplier<T> : What 'T' is type ,return value is type
    // T 是什么类型，supplier中方法get返回值就是什么类型
    public static Integer method_01_Supplier(Supplier<Integer> supplier) {
    
    
        return supplier.get();
    }

    public static Integer method_02_Supplier(Supplier<Integer> supplier) {
    
    
        return supplier.get();
    }

    // @FunctionalInterface Consumer
    // this is consumer interface
    public static void method_01_Consumer(String str_number, Consumer<String> consumer) {
    
    
        consumer.accept(str_number);
    }

    // this is consumer interface
    public static void method_02_Consumer(String[] str_number, Consumer<String> consumer1, Consumer<String> consumer2) {
    
    
        for (String message : str_number) {
    
    
            consumer1.andThen(consumer2).accept(message);
        }
    }

    // @FunctionalInterface Predicted
    public static Boolean method_Predicted_01(Integer num, Predicate<Integer> predicate) {
    
    
        return predicate.test(num);
    }

    public static Boolean method_Predicted_02(Integer num, Predicate<Integer> predicate1, Predicate<Integer> predicate2) {
    
    
        return predicate1.and(predicate2).test(num);
    }

    public static Boolean method_Predicted_03(Integer num, Predicate<Integer> predicate1, Predicate<Integer> predicate2) {
    
    
        return predicate1.or(predicate2).test(num);
    }

    public static Boolean method_Predicted_04(Integer num, Predicate<Integer> predicate1) {
    
    
        return predicate1.negate().test(num);
    }

    // @FunctionalInterface Predicted
    public static void method_Function_apply(String number , Function<String,Integer> fun){
    
    
        System.out.println(number + "\tType : " +number.getClass().getName());
        Integer integer = fun.apply(number);
        System.out.println(integer + "\tType : " +integer.getClass().getName());
    }

    public static void method_Function_andThen(String number , Function<String,Integer> fun1,Function<Integer,String> fun2){
    
    
        String apply = fun1.andThen(fun2).apply(number);
        System.out.println(apply + " Type is :  " +apply.getClass().getName());
    }

    public static Integer method_Function_andThen1(String[] str_arr , Function<String,Integer> fun1,Function<Integer,Integer> fun2){
    
    
        Integer sum = 0 ;
        for (String massage : str_arr)
            sum += fun1.andThen(fun2).apply(massage);
        return sum;

    }
}