JAVA8函数式接口

java8 中内置的四大核心函数接口
*
* Consumer<T> ：消费型接口
*         void accept(T t)
* Supplier<T> :供给型接口
*          T get()
*
* Function<T,R>:函数型接口
*          R apply(T t)
* Predicate<T> :断言型接口
*          boolean test(T t)

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package airycode_java8.nice4;   import org.junit.Test;   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 中内置的四大核心函数接口  *  * Consumer<T> ：消费型接口  *         void accept(T t)  * Supplier<T> :供给型接口  *          T get()  *  * Function<T,R>:函数型接口  *          R apply(T t)  * Predicate<T> :断言型接口  *          boolean test(T t)  * Created by admin on 2019/1/2.  */ public class TestLambda {       @Test     public void test1(){         happy(10000,(m)-> System.out.println("大保健，每次消费"+m));     }       @Test     public void test2(){         getNumList(10,()-> (int)(Math.random()*100));     }       //函数型接口     @Test     public void test3(){           String result = handler("aa", (str) -> str.toUpperCase());         System.out.println(result);         }         //断言型接口     @Test     public void test4(){           List<String> list = Arrays.asList("Hello","AA","CCCC");         List<String> resultList = filterStr(list, (str) -> str.length() > 3);         for (String str:resultList) {             System.out.println(str);         }         }       //需求：我要将满足条件的字符串放入集合中     public List<String> filterStr(List<String> list, Predicate<String> pre){         List<String> result = new ArrayList<>();         for (String str:list) {             if (pre.test(str)) {                 result.add(str);             }         }         return result;     }               //需求：用于处理字符串     public String handler(String string, Function<String,String> fun){         return fun.apply(string);     }             public void happy(double money, Consumer<Double> consumer){         consumer.accept(money);     }       public List<Integer> getNumList(int num, Supplier<Integer> supplier){         List<Integer> result = new ArrayList<>();         for (int i=0;i<num;i++) {             Integer n = supplier.get();             result.add(n);         }         return result;     }   }