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我有一个案例，我通过一系列查询构造一个对象。为了优化，对象的构造是一起批处理的，查询使用IN子句来允许处理一批对象。

在下面的示例中，给定 的列表MyObject，我想MyObject.c根据 和 的值MyObject.a进行填充MyObject.b。使用skife.jdbi 库，我的实现如下所示。

有什么改进建议吗？

如果我解析原始结果集可能会更有效（尽管我找不到如何让我的界面来映射结果集）？

或者，如果有某种方法可以直接将查询参数映射到结果（但我还没有找到方法），它会更整洁吗？

class MyObject {
String a;
String b;
String c;

// ....

String z;

}

void populateC(Set<MyObject> objects) {
  // parse the list, populating Lists which will be used for the query and a 
  // Map which will be used to map query results back to the MyObjects in the Set param

  Map<PopulateCQuerydata, MyObject> queryDataToParamMap = new HashMap<>;
  List<String> aList = new ArrayList<>;
  List<String> bList = new ArrayList<>;


  for (MyObject object : objects) {
     queryDataToParamMap.put(new CResult(object), object);
     aList.add(object.a);
     bList.add(object.b);
  }  


  Set<CResult> results = dao.getC(aList, bList);

  for (CResult result : results) {
    queryDataToParamMap.get(result).c = result.c;
  }

}

@RegisterMapper(CResultMapper.class)
@UseStringTemplate3StatementLocator("/sql/PopulateCDao.sql.stg")
interface PopulateCDao {
  @SqlQuery
  List<CResults> getC(@BindIn("aList") List<String> a, @BindIn("bList") List<String> b);
}

class CResults {
  String a;
  String b;
  String c;

  CResults(MyObject object) {
    a = object.a;
    b = object.b;
  }

// implement these so this type can be used in the HashMap
  @Override
 public boolean equals(Object other) {
   if (this == other) {
     return true;
   } else if (!(other instanceof CResults )) {
        return false;
   } else {
      CResults otherQueryData = (CResults)other;
        return a.equals(otherQueryData.a) && b.equals(otherQueryData.b);
    }
   }

    @Override
    public int hashCode() {
      int hash = 1;
      hash = hash * 31 + a.hashCode() + b.hashCode();
      return hash;
    }

}

public class CResultMapper implements ResultSetMapper<CResult> {

  @Override
  public CResult map(int index, ResultSet resultSet, StatementContext statementContext) throws SQLException  {

    CResult result = new CResult();
    result.a = resultSet.getInt("a");
    result.b = resultSet.getInt("b");
    result.c = resultSet.getInt("c");

    return result;
  }
}

//sql/PopulateCDao.sql.stg

group PopulateCDao;

getC(aList, bList) ::= <<
    SELECT a, b, c FROM tblJoinC WITH (NOLOCK) WHERE a IN (<aList>) AND b IN (<bList>)
>>
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