Predicate接口和Consumer接口

Posted 2020-08-06 MazeHong

　　Predicate和Consumer接口是集合操作中常用到的俩个接口：

1、Predicate

public interface Predicate<T>{
	boolean test(T t);//进行某些逻辑判断并返回一个boolean值
}

2、Consumer

public interface Consumer<T>{
	void accept(T t);//对于给定的对象进行操作
}

3、结合实例

import java.util.Collection;
import java.util.HashSet;
import java.util.function.Predicate;
import java.util.function.Consumer;
public class PreCon{
	public static void main(String []args){
		Collection<String> c=new HashSet<String>();
		c.add("!");
		c.add("java");
		c.add("hao");
		c.add("ni");
		c.add("zhe");		
		System.out.println(findSet(c,obj->System.out.println(obj),obj->((String)obj).length()<3));
	}
	public static int findSet(Collection collection,Consumer consumer,Predicate predicate){
		int n=0;
		for(Object obj:collection){
			if(predicate.test(obj)){
			n++;
			consumer.accept(obj);
			}
		}
		return n;
	}
}