JAVA 交集,差集,并集

本来是想用apache 的commons-collections

以下为MAVEN依赖:

 <dependency>
		<groupId>commons-collections</groupId>
		<artifactId>commons-collections</artifactId>
		<version>3.2.1</version>
	</dependency>    

 

后来网友们说不需要,直接用JDK的API就可以了,以下给出实现:

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.collections.ListUtils;
public class TestList {

	public void Test(){
		  List list1=new ArrayList();
		  list1.add(1);
		  list1.add(2);
		  list1.add(3);
		  list1.add(4);
		  
		  List list2=new ArrayList();
		  list2.add(1);
		  list2.add(2);
		  list2.add(5);
		  list2.add(6);
		  List intersection = new ArrayList(list1);
		  print(intersection);
		  boolean is  = intersection.retainAll(list2); // 不需要用APATCH的包,intersection里面放的就是交集.
		  System.out.println("intersection");
		  print(intersection);
		  List  subtractList = new  ArrayList(list1);
	
		  boolean ischaji = subtractList.removeAll(list2); // 结果是subtractList里放的是差集.
		  System.out.println("substarct 差集");
		  print(subtractList);
		
		  
		  List Listunion = new  ArrayList(list1);
		  boolean isunion = Listunion.addAll(list2); // 结果是LIST1放的是有重复并集
		  System.out.println("union");
		  print(Listunion);
		  
		  
		  //以下求无重复并集,未排序.
		  List ListSigleUnion = new  ArrayList(list1);
		  boolean issigelunio = ListSigleUnion.removeAll(list2);
		  issigelunio =  ListSigleUnion.addAll(list2);
		
		  System.out.println("sigle union");
		  print(ListSigleUnion);
		 
		 }
		 
	  private void print (Collection o)
	  {
		  Iterator it = o.iterator();
	        while(it.hasNext()) {
	            Object obj = it.next();
	            System.out.println(obj.toString());
	        }
	  }
	 public static void main(String[] args) {
		 TestList test=new TestList();
	     test.Test();
	 }
}

简单看了下apache 的包,打算还是用GOOGLE的吧,因为前者时间太久远了.