Java8中内置的四大核心函数式接口

package com.expgiga.Java8;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;

/**
 * Java8内置的四大核心函数式接口
 *
 * 1.Consumer<T>：消费型接口
 * void accept(T t);
 * 2.Supplier<T>：供给型接口
 * T get();
 * 3.Function<T, R>：函数型接口
 * R apply(T t);
 * 4.Predicate<T>：断言型接口
 * boolean test(T t);
 */
public class TestLambda3 {
public static void main(String[] args) {
//Consumer<T>消费型接口
 happy(10000, (m) -> System.out.println("Play Game!: " + m + " yuan"));

//Supplier<T>
 List<Integer> numList = getNumList(10, () -> (int) (Math.random() * 100));
for (Integer num : numList) {
            System.out.println(num);
        }

//Function<T, R>函数型接口
 String newStr = strHandler("\t\t\t 你牛逼 ", (str) -> str.trim());
        System.out.println(newStr);

        String subStr = strHandler("我也牛逼，大家都牛逼", (str) -> str.substring(2, 5));
        System.out.println(subStr);

//Predicate<T> 断言型接口
 List<String> list = Arrays.asList("Hello", "you", "me", "Java", "Scala");
        List<String> newlist = filterStr(list, (s) -> s.length() > 3);
for (String str : newlist) {
            System.out.println(str);
        }
    }

private static void happy(double money, Consumer<Double> con) {
        con.accept(money);
    }

//需求：产生一些整数，并放入集合中
 private static List<Integer> getNumList(int num, Supplier<Integer> sup) {
        List<Integer> list = new ArrayList<>();

for (int i = 0; i < num; i++) {
            Integer n = sup.get();
            list.add(n);
        }

return list;
    }

//需求：用于处理字符串
 private static String strHandler(String str, Function<String, String> fun) {
return fun.apply(str);
    }

//需求：将满足条件的字符串放入集合中去
 private static List<String> filterStr(List<String> list, Predicate<String> predicate) {
        List<String> strList = new ArrayList<>();

for (String str : list) {
if (predicate.test(str)) {
                strList.add(str);
            }
        }

return strList;
    }

}