Java_collection JDK8 中 collection接口的RemoveIf方法；Iterator接口forEachRemaining方法

浅浅的花香味﹌ 2022-11-14 10:27 178阅读 0赞

### Java\_collection 集合框架 ###

*  \*\*通过下面例子学习collection接口的RemoveIf方法；Iterator接口forEachRemaining方法\*\*
 *  forEachRemaining
 *  removeIf

# **通过下面例子学习collection接口的RemoveIf方法；Iterator接口forEachRemaining方法** #

package cn.ling.collection;
    
    import java.util.ArrayList;
    import java.util.Iterator;
    import java.util.List;
    
    //collection 接口 removeIf方法 删除满足某个条件的元素
    public class RemoveIf { 
        public static void main(String[] args) { 
            List<String> strList = new ArrayList<>();
            strList.add("apple");
            strList.add("apple1");
            strList.add("apple2");
            strList.add("apple3");
            strList.add("apple4");
            strList.add("banana");
            strList.add("1banana");
            strList.add("2banana");
            strList.add("3banana");
            strList.add("43banana");
    
            Iterator<String> iterators = strList.iterator();
            while (iterators.hasNext()){ 
                System.out.print(iterators.next()+ " ");
            }
    
            System.out.println();
            System.out.println("--------------------------------");
    
            strList.iterator().forEachRemaining((str)-> System.out.print(str+ " "));
    
            strList.removeIf((str)-> str.startsWith("a"));
    
            System.out.println();
            System.out.println("--------------------------------");
            strList.iterator().forEachRemaining((str)->System.out.print(str+ " "));
        }
    }

这个两个方法都要是用到Lambda表达式。

# forEachRemaining #

相当于循环执行目标函数的实现

default void forEachRemaining(Consumer<? super E> action) { 
         Objects.requireNonNull(action);
         while (hasNext())
         	 //执行目标函数的函数体 Consumer是函数式接口
             action.accept(next());
     }

strList.iterator().forEachRemaining((str)-> System.out.print(str+ " "));

上面写法不懂，可以参考：[https://blog.csdn.net/lingyiwin/article/details/109212540][https_blog.csdn.net_lingyiwin_article_details_109212540]

# removeIf #

实现过滤筛选的功能

default boolean removeIf(Predicate<? super E> filter) { 
        Objects.requireNonNull(filter);
        boolean removed = false;
        final Iterator<E> each = iterator();
        while (each.hasNext()) { 
        	//如果匹配成功 执行remove方法
            if (filter.test(each.next())) { 
                each.remove();
                removed = true;
            }
        }
        return removed;
    }

[https_blog.csdn.net_lingyiwin_article_details_109212540]: https://blog.csdn.net/lingyiwin/article/details/109212540