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这里简单介绍下，如何使用apache commons以及guava的类库来计算集合的交差并集。

maven

                
     
      com.google.guava
                 
     
      guava
                 
     
      22.0
             
            
                
     
      org.apache.commons
                 
     
      commons-collections4
                 
     
      4.1
             
    

guava

//交集        Set
    
      intersectionSet = Sets.intersection(set1, set2);        //差集        Set
     
       subtractSet = Sets.difference(set1, set2);        //并集        Set
      
        unionSet = Sets.union(set1, set2);
      
     
    

commons-collection4

//交集        Collection
    
      intersectionSet = CollectionUtils.intersection(set1, set2);        //差集        Collection
     
       subtractSet = CollectionUtils.subtract(set1, set2);        //并集        Collection
      
        unionSet = CollectionUtils.union(set1, set2);