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): {,,}