用法 判断集合是否为空 CollectionUtils.isEmpty(null): trueCollectionUtils.isEmpty(new ArrayList()): true CollectionUtils.isEmpty({a,b}): false 判断集合是否不为空 CollectionUtils.isNotEmpty(null): falseCollectionUtils.isNotEmpty(new ArrayList()): falseCollectionUtils.isNotEmpty({a,b}): true public static boolean isEmpty(Collection coll) （org.apache.commons.collections.CollectionUtils）和public boolean isEmpty()（java.util.ArrayList;）的区别 代码 import org.apache.commons.collections.CollectionUtils;import java.util.ArrayList;public class demo { public static void main(String[]args) { ArrayList arrayList1 = new ArrayList(); ArrayList arrayList2 = null; //① System.out.println(CollectionUtils.isEmpty(arrayList1)); //② System.out.println(arrayList1.isEmpty()); //③ System.out.println(CollectionUtils.isEmpty(arrayList2)); //④ System.out.println(arrayList2.isEmpty()); }} 结果