集合的常用操作類CollectionUtils

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

package com.jakin.util;


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");
        // 並集
        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);
        // 交集的補集
        Collection<String> disjunctionList = CollectionUtils.disjunction(aList, bList);
        // 集合相減
        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);


        // 測試
        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()));


    }
}