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[] { "", "", "", "", "", "" };

   String[] arrayB = new String[] { "", "", "", "", "", "" };

   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: {,,,,,}

　　B: {,,,,,}

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

　　Union(A, B): {,,,,,,,,}

　　Intersection(A, B): {,,}

　　Disjunction(A, B): {,,,,,}

　　Subtract(A, B): {,,}