java list 交集并集差集去重复并集

傷城~ 2022-04-06 02:47 387阅读 0赞

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