包括:MapUtils,SetUtils
JDK自带的Arrays,Collections,System.arraycopy
都非常好用
package test.ArrayToList; import java.util.ArrayList; import java.util.List; import org.apache.commons.collections.CollectionUtils; public class Test { public static void main(String[] args) { List<Integer> list = new ArrayList<Integer>(); String[] myString = new String[] { "1", "2", "hello array!" }; CollectionUtils.addAll(list, myString); System.out.println(list.get(0)); System.out.println(list.get(1)); System.out.println(list.get(2)); } }
package test.collectionsUtils; import java.util.ArrayList; import java.util.List; import org.apache.commons.collections.CollectionUtils; public class Test { public static void main(String[] args) { List<Object> list = new ArrayList<Object>(); List<Object> list2 = null; System.out.println("isEmpty=" + CollectionUtils.isEmpty(list)); System.out.println("isNotEmpty=" + CollectionUtils.isNotEmpty(list)); System.out.println("isEmpty=" + CollectionUtils.isEmpty(list2)); list.add(1); System.out.println("isEmpty=" + CollectionUtils.isEmpty(list)); } }