java list 交集 并集 差集 去重复并集

Array基本操作

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class TestCollection {

	public static void main(String[] args) {
		List list1 = new ArrayList();
		list1.add("1111");
		list1.add("2222");
		list1.add("3333");

		List list2 = new ArrayList();
		list2.add("3333");
		list2.add("4444");
		list2.add("5555");

		// 并集
		// list1.addAll(list2);
		// 交集
		// list1.retainAll(list2);
		// 差集
		// list1.removeAll(list2);
		// 无重复并集
		list2.removeAll(list1);
		list1.addAll(list2);

		Iterator<String> it = list1.iterator();
		while (it.hasNext()) {
			System.out.println(it.next());

		}

		// System.out.println("-----------------------------------\n");
		// printStr(list1);

	}

	public static void printStr(List list1) {
		for (int i = 0; i < list1.size(); i++) {
			System.out.println(list1.get(i));
		}
	}
}

 

二、使用commons CollectionUtils工具类

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang.ArrayUtils;

public class CollectionUtilsTest {

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {

        List<String> aList = new ArrayList<String>();
        aList.add("aaa");
        aList.add("bbb");
        aList.add("ccc");
        List<String> bList = new ArrayList<String>();
        bList.add("aaa");
        bList.add("ddd");
        bList.add("eee");
        // 并集
        Collection<String> unionList = CollectionUtils.union(aList, bList);
        // 交集
        Collection<String> intersectionList = CollectionUtils.intersection(aList, bList);
        // 是否存在交集
        boolean isContained = CollectionUtils.containsAny(aList, bList);
        // 交集的补集
        Collection<String> disjunctionList = CollectionUtils.disjunction(aList, bList);
        // 集合相减
        Collection<String> subtractList = CollectionUtils.subtract(aList, bList);
        
        // 排序
        Collections.sort((List<String>) unionList);
        Collections.sort((List<String>) intersectionList);
        Collections.sort((List<String>) disjunctionList);
        Collections.sort((List<String>) subtractList);

        // 测试
        System.out.println("A: " + ArrayUtils.toString(aList.toArray()));
        System.out.println("B: " + ArrayUtils.toString(bList.toArray()));
        System.out.println("A has one of B? : " + isContained);
        System.out.println("Union(A, B): "
                + ArrayUtils.toString(unionList.toArray()));
        System.out.println("Intersection(A, B): "
                + ArrayUtils.toString(intersectionList.toArray()));
        System.out.println("Disjunction(A, B): "
                + ArrayUtils.toString(disjunctionList.toArray()));
        System.out.println("Subtract(A, B): "
                + ArrayUtils.toString(subtractList.toArray()));

    }
}

 

参考：

java list 交集 并集 差集 去重复并集

http://www.blogjava.net/yourfriend/articles/377755.html

 

集合的常用操作类CollectionUtils

http://www.blogjava.net/jakin/archive/2009/05/14/270634.html