在没有结果集的情况下使用JDBC Spring读取BLOB [英] Reading a BLOB using JDBC Spring without a result set

问题描述

我有一个Oracle存储过程，该存储过程在输出参数中返回BLOB:

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;

我想使用JDBC Spring读取此数据.但是，DefaultLobHandler(我认为是OracleLobHandler)的getBlobAsBytes()需要一个结果集.

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;
        }   
    }   

当我所有的都是out参数而不是结果集时，如何获取blob数据?

How can I get the blob data when all I have is an out parameter and not a resultset?

推荐答案

JDBC Spring API(

The JDBC Spring API (DefaultLobHandler and OracleLobHandler) require a ResultSet object for their BLOB related methods.

您需要将GET_IMAGE_DATA 过程转换为功能:

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参数对于某些悲伤尤其是BLOB总是很有益的.

OUT parameters are always good for some grief, BLOBs especially.

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