Java collection 集合差操作

package com.suypower.xssystem.temp;
/*
 *电量数据同步
 *@author chengYu
 *@param connection
 *@return arrayA,arrayB
 */
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.*;
import java.util.ArrayList;
import com.suypower.xssystem.dao.dbconn;
import java.util.List;
import java.util.Collection;

import org.apache.commons.collections.CollectionUtils;
import java.util.Arrays;

public class ReturnArray{
  public ReturnArray(){}
  public static void main(String[] args) {
                 dbconn.isPool = false;
                 String filename = null;
                 if (args.length == 0)
                 return;
                 if (args[0] == null) {
                 return;
                 } else {
                 filename = ".//" + args[0];
                 }
                 dbconn.setDataSourse(filename);
                 dbconn db = new dbconn();
    /**
     * connect to db2 tb_gd_xl and tb_fxs
     * param lyid and xldm
     * return arrayA,arrayB
     */
    Connection con = null;
    try
    {
      con = db.getConnection();
      Statement stmt = con.createStatement();

      String sqlA = "select xldm from tb_gd_xl where xldm is not null";
      ResultSet rsA =stmt.executeQuery(sqlA);

      ArrayList arrayA = new ArrayList();
      ArrayList arrayB = new ArrayList();
      while(rsA.next())
      {
        String xldm = rsA.getString("xldm");
        arrayA.add(xldm);
      }
      String sqlB = "select lyid from tb_fxs where lyid is not null";
      ResultSet rsB = stmt.executeQuery(sqlB);
      while(rsB.next())
      {
        String lyid = rsB.getString("lyid");
        arrayB.add(lyid);
      }
     /**
      * 实现差操作
      */
     List a = Arrays.asList(arrayA.toArray());
     List b = Arrays.asList(arrayB.toArray());
     Collection subtract = CollectionUtils.subtract(a,b);

     ArrayList arraylistC = new ArrayList(subtract);

     for(int i=0;i<arraylistC.size();i++)
     {
       System.out.println((String)arraylistC.get(i));
     }
     /**
      * 实现 插入 数据库 相应 节点 更新
      */
     }catch(Exception e)
    {
      e.printStackTrace();
    }
     finally
       {
        try {
          if (con != null) {
            con.close();
          }
        }
        catch (SQLException ex) {
          ex.printStackTrace();
        }
         }
       }
}