我有一个存储过程，它正在从JpaRepository实现中调用
@Repository
public interface DataMartRepo extends JpaRepository<DataMartDAO, String> {
@Procedure(procedureName = "dbo.txn_ETL")
public void txnETL(
@Param("txId") String txId,
@Param("inId") String inId,
@Param("proc") String proc,
@Param("qtys") String qtys);
现在，这工作正常，期望当“proc”为空值时，在这种情况下它会引发异常：
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/Authenticator]
threw exception [Request processing failed; nested exception is org.springframework.orm.jpa.JpaSystemException:
Error calling CallableStatement.getMoreResults; nested exception is org.hibernate.exception.GenericJDBCException:
Error calling CallableStatement.getMoreResults] with root cause
com.microsoft.sqlserver.jdbc.SQLServerException: The value is not set for the parameter number 3.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:190)
at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.buildParamTypeDefinitions(SQLServerPreparedStatement.java:260)
at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.buildPreparedStrings(SQLServerPreparedStatement.java:219)
at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.doPrepExec(SQLServerPreparedStatement.java:612)
at com.microsoft.sqlserver.jdbc.SQLServerPreparedStatement.doExecutePreparedStatement(SQLServerPreparedStatement.java:400)
[...]
如何处理空值？将所有字符串设置为“”不提供空插入。