Do you know how to init list in other way except for new object? The following will give you serveral tips. If having other great idea, you are welcome to share.
- import java.util.ArrayList;
- import java.util.Arrays;
- import java.util.Collections;
- import java.util.List;
- public class ListUtil
- {
- /**
- *Init the List with different methods.
- *
- * @time Jul 21, 2014 5:39:10 PM
- * @return void
- */
- public static void init()
- {
- // use new to init List
- List<String> firstList = new ArrayList<String>(0);
- firstList.add("ABC");
- firstList.add("FGF");
- firstList.add("CID");
- System.out.println(firstList);
- // use the string to init List
- List<String> testList = Arrays.asList("ABC", "FGF", "CID");
- System.out.println(testList);
- //output:[ABC, ABC, GFG, CID]
- /**
- * Notes: The following methods is dependent on the above List.
- */
- //use arrays and copy to init List
- List<String> copyList = Arrays.asList(new String[testList.size()]);
- Collections.copy(copyList,testList);
- System.out.println(copyList);
- //use new object and copy to init List
- copyList = new ArrayList<String>();
- Collections.addAll(copyList, new String[testList.size()]);
- Collections.copy(copyList,testList);
- System.out.println(copyList);
- //use the list.subList to init List
- List<String> strSubList = testList.subList(0, testList.size());
- System.out.println(strSubList);
- };
- public static void main(String[] args)
- {
- ListUtil.init();
- }
- }
The result is :
- [ABC, FGF, CID]
- [ABC, FGF, CID]
- [ABC, FGF, CID]
- [ABC, FGF, CID]
- [ABC, FGF, CID]