java7中的List中使用filter過濾出符合特定條件的元素List

1.定義一個 ListFilterStrategy 接口，實現過濾條件封裝

/**
 * @Auther: wuzheng
 * @Date: 2018/12/5 14:01
 * @Description:  定義List過濾基本方法
 */
public interface ListFilterStrategy<T> {

    public boolean contain(T t);
}

2.ListUtils 實現

/**
 * @Auther: wuzheng
 * @Date: 2018/12/5 13:56
 * @Description: List工具類，存放一些比較常用的公共部分功能
 */
public final class ListUtils {
    /**
     * 根據條件對List進行過濾
     * @param list
     * @param strategy
     * @param <T>
     * @return
     */
    public static <T> List<T> filter(List<T> list, ListFilterStrategy<T> strategy) {
        List<T> rList = new ArrayList<>();
        if(CollectionUtils.isNotEmpty(list)){
            for (int i = 0; i < list.size(); i++) {
                T t =  list.get(i);
                if (strategy.contain(t)){
                    rList.add(t);
                }
            }
        }
        ((ArrayList<T>) rList).trimToSize();//釋放申請的多餘的空間
        return rList;
    }

    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();
        for (int i = 0; i <10; i++) {
            list.add(i);
        }
        final List<Integer> alist = Arrays.asList(1, 2, 3);
        List<Integer> rList=filter(list, new ListFilterStrategy<Integer>() {
            @Override
            public boolean contain(Integer integer) {
                return alist.contains(integer);
            }
        });
        System.out.println(rList.size());
    }