JAVA集合操作的利器:CollectionUtils

使用 CollectionUtils 中四个方法之一执行集合操作.这四种分别是 union(),intersection();disjunction(); subtract();

下列例子就是演示了如何使用上述四个方法处理两个 Collection;

import java.util.Arrays;      

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 CollectionUtilsIntro {    

  @SuppressWarnings("unchecked")      

  public static void main(String[] args) {      

   String[] arrayA = new String[] { "1", "2", "3", "3", "4", "5" };      

   String[] arrayB = new String[] { "3", "4", "4", "5", "6", "7" };              

   List<String> a = Arrays.asList(arrayA);      

   List<String> b = Arrays.asList(arrayB);      

   //并集      

   Collection<String> union = CollectionUtils.union(a, b);      

   //交集      

   Collection<String> intersection = CollectionUtils.intersection(a, b);      

   //交集的补集      

   Collection<String> disjunction = CollectionUtils.disjunction(a, b);      

   //集合相减      

   Collection<String> subtract = CollectionUtils.subtract(a, b);              

   Collections.sort((List<String>) union);      

   Collections.sort((List<String>) intersection);      

   Collections.sort((List<String>) disjunction);      

   Collections.sort((List<String>) subtract);              

   System.out.println("A: " + ArrayUtils.toString(a.toArray()));      

   System.out.println("B: " + ArrayUtils.toString(b.toArray()));      

   System.out.println("--------------------------------------------");      

   System.out.println("Union(A, B): " + ArrayUtils.toString(union.toArray()));      

   System.out.println("Intersection(A, B): " + ArrayUtils.toString(intersection.toArray()));      

   System.out.println("Disjunction(A, B): " + ArrayUtils.toString(disjunction.toArray()));      

   System.out.println("Subtract(A, B): " + ArrayUtils.toString(subtract.toArray()));      

  }      

}

 

　　输出如下：

　　A: {1,2,3,3,4,5}

　　B: {3,4,4,5,6,7}

　　--------------------------------------------

　　Union(A, B): {1,2,3,3,4,4,5,6,7}

　　Intersection(A, B): {3,4,5}

　　Disjunction(A, B): {1,2,3,4,6,7}

　　Subtract(A, B): {1,2,3}