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}