使用Spring jdbc template调用Sybase带有返回结果集的储存过程-要点

关键字: Spring   spring    

google半天，没找到有人写者方面的，我就开个头吧。有不对的地方还请大侠们拍砖。
要点其实很简单，就是把在declareParameter时要先声明返回结果集参数，再声明input参数。

先看看程序吧：
Sybase 存储过程

代码

IF OBJECT_ID('dbo.sp_xx') IS NOT NULL
BEGIN
    DROP PROCEDURE dbo.sp_xx
    IF OBJECT_ID('dbo.sp_xx') IS NOT NULL
        PRINT '<<< FAILED DROPPING PROCEDURE dbo.sp_xx >>>'
    ELSE
        PRINT '<<< DROPPED PROCEDURE dbo.sp_xx >>>'
END
go
create proc sp_xx ( @userid int)
as
begin
    select personid, personname from person where personid = @userid

    select teamid, teamname from team
end

EXEC sp_procxmode 'dbo.sp_xx','unchained'
go

<script>render_code();</script>
正确的java调用程序如下

代码

private class ProcWithResultSet extends StoredProcedure
{
    public ProcWithResultSet(DataSource dataSource)
    {
        setDataSource(dataSource);
        setSql("sp_xx");

        //declareParameter(new SqlParameter("userid", java.sql.Types.INTEGER));              //(1)
        //declare the first out param in the sp, the name rsPerson is the key of result map
        declareParameter(new SqlReturnResultSet("rsPerson", new PersonRowMapper()));
        //declare the second out param in the sp, the name rsTeam is the key of result map
        declareParameter(new SqlReturnResultSet("rsTeam", new TeamRowMapper()));
    //declare input params, the name userid is the IN params of the param
        declareParameter(new SqlParameter("userid", java.sql.Types.INTEGER));                //(2)

        compile();
    }

    public Map getRsFromSP(int userID)
    {

        Map map = new HashMap();
        map.put("userid", new Integer(userID));
        return execute(map);
    }
}

private class PersonRowMapper implements RowMapper
{
public Object mapRow(ResultSet rs, int rowNum) throws SQLException
{
    UserInfo u = new UserInfo();
    u.setPersonID(rs.getInt(1));
    u.setUserName(rs.getString(2));
    return u;
}
}
private class TeamRowMapper implements RowMapper
{
public Object mapRow(ResultSet rs, int rowNum) throws SQLException
{
    return new PropertyValue(rs.getInt(1)+"", rs.getString(2));
}
}

<script>render_code();</script>
Spring中对于jdbc 调用带有返回结果集的存储过程是用的这个方法。

代码

 /**
 * Extract returned ResultSets from the completed stored procedure.
 * @param cs JDBC wrapper for the stored procedure
 * @param parameters Parameter list for the stored procedure
 * @return Map that contains returned results
 */
protected Map extractReturnedResultSets(CallableStatement cs, List parameters, int updateCount)
        throws SQLException {

    Map returnedResults = new HashMap();
    int rsIndex = 0;
    boolean moreResults;
    do {
        if (updateCount == -1) {                 //(3)
            Object param = null;
            if (parameters != null && parameters.size() > rsIndex) {
                param = parameters.get(rsIndex);     //(4)
            }
            if (param instanceof SqlReturnResultSet) {
                SqlReturnResultSet rsParam = (SqlReturnResultSet) param;
                returnedResults.putAll(processResultSet(cs.getResultSet(), rsParam)); //(5)
            }
            else {
                logger.warn("Results returned from stored procedure but a corresponding " +
                        "SqlOutParameter/SqlReturnResultSet parameter was not declared");
            }
            rsIndex++;
        }
        moreResults = cs.getMoreResults();           //(6)
        updateCount = cs.getUpdateCount();
        if (logger.isDebugEnabled()) {
            logger.debug("CallableStatement.getUpdateCount() returned " + updateCount);
        }
    }
    while (moreResults || updateCount != -1);
    return returnedResults;
}

<script>render_code();</script>

 

原因分析：
1：Sybase不支持Out 参数返回结果集。只能再Sp当中最后select column from some table
2：Sybase的JDBC Driver对于jdbc的实现比较令人费解，如果一个Sp返回多个结果集，如果不调用第一个结果集即statement.getResultSet()
那么接下来statementcs.getMoreResults()会返回False,即使有有第二个返回结果集，它一样返回false,那么Spring就会把返回结果认为是一个update的
结果，就不会对其它结果集进行处理。
3：Spring中如果jdbc返回结果集，那么程序会执行到(3)处，这里rsIndex = 0，如果输入参数声明在先，那么这里得到的将会是输入参数，
(5)处的cs.getResultSet()将不会被执行，第一个ResultSet不会被处理，同时，因为(5)处没有被执行，那么(6)处会返回false,也就是解下来
的结果集不会被正确的认出来，Spring也不会去处理后续的结果集，这样就一个结果集也得不到了。
4：这里主要还是Sybase jdbcDriver在实现jdbc时有bug,但是我们只能顺着人家来，在用Spring Jdbctemplate调用时注意一下了。