问题
I have an Oracle stored procedure that returns a BLOB in an output parameter:
PROCEDURE GET_IMAGE_DATA(i_image_type IN NUMBER, o_image_data OUT BLOB) IS
BEGIN
SELECT IMAGE_DATA
INTO o_image_data
FROM IMAGES
WHERE IMAGE_TYPE = i_image_type;
END GET_IMAGE_DATA;
I want to use JDBC Spring to read this data. However, DefaultLobHandler (and I think OracleLobHandler) getBlobAsBytes() requires a resultset.
private static class QueryForBinaryCryptKey extends StoredProcedure {
private static final String SQL = "IMAGE_PKG.GET_IMAGE_DATA";
private DefaultLobHandler lobHandler;
QueryForImageData(DataSource dataSource) {
super(dataSource, SQL);
setFunction(false);
lobHandler = new DefaultLobHandler();
declareParameter(new SqlParameter(KEY_TYPE, OracleTypes.NUMBER));
declareParameter(new SqlOutParameter(KEY_BLOB, OracleTypes.BLOB));
}
public Map getImage(int keyType) {
Map outParams = super.execute(inParams(keyType));
//how can I get the contents of the blob right here since
//getBlobAsBytes requires a resultSet???
return outParams;
}
private Map inParams(int keyType) {
Map params = new HashMap();
params.put(KEY_TYPE, new Integer(keyType));
return params;
}
}
How can I get the blob data when all I have is an out parameter and not a resultset?
回答1:
The JDBC Spring API (DefaultLobHandler and OracleLobHandler) require a ResultSet object for their BLOB related methods.
You need to convert your GET_IMAGE_DATA procedure into a function:
FUNCTION ATTACHMENT_BLOB_GET(IN_IMAGE_TYPE IN IMAGES.IMAGE_TYPE%TYPE)
RETURN SYS_REFCURSOR AS
results_cursor SYS_REFCURSOR;
BEGIN
OPEN results_cursor FOR
SELECT t.image_data
FROM IMAGES t
WHERE t.image_type = IN_IMAGE_TYPE;
RETURN results_cursor;
END;
OUT parameters are always good for some grief, BLOBs especially.
回答2:
It is indeed possible to read Blob as Stream/byte[] without a ResultSet. Check this one out.
来源：https://stackoverflow.com/questions/1474456/reading-a-blob-using-jdbc-spring-without-a-result-set