集合操作

Commons Collectons 里面可能有你想要的答案,看一下CollectionUtils类

String[] arrayA = new String[] { "1", "2", "3", "3", "4", "5" };
String[] arrayB = new String[] { "3", "4", "4", "5", "6", "7" };

List a = Arrays.asList( arrayA );
List b = Arrays.asList( arrayB );

Collection union = CollectionUtils.union( a, b );
Collection intersection = CollectionUtils.intersection( a, b );
Collection disjunction = CollectionUtils.disjunction( a, b );
Collection subtract = CollectionUtils.subtract( a, b );

Collections.sort( union );
Collections.sort( intersection );
Collections.sort( disjunction );
Collections.sort( subtract );

System.out.println( "A: " + ArrayUtils.toString( a.toArray( ) ) );
System.out.println( "B: " + ArrayUtils.toString( b.toArray( ) ) );
System.out.println( "Union: " + ArrayUtils.toString( union.toArray( ) ) );
System.out.println( "Intersection: " +
                    ArrayUtils.toString( intersection.toArray( ) ) );
System.out.println( "Disjunction: " +
                    ArrayUtils.toString( disjunction.toArray( ) ) );
System.out.println( "Subtract: " + ArrayUtils.toString( subtract.toArray( ) ) );

ArrayUtils.toString( ):

A: {1,2,2,2,3,3,4,5}
B: {3,4,4,5,6,7}
Union: {1,2,2,2,3,3,4,4,5,6,7}
Intersection: {3,4,5}
Disjunction: {1,2,2,2,3,4,6,7}
Subtract: {1,2,2,2,3}[/code]