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JdbcTemplate - Insert or update Oracle BLOB using SQL MERGE

由 人盡茶涼 提交于 2019-12-01 23:21:15
kpater87

I solved the problem thanks to @gvenzi answer, but decided to post my own answer as I have some additional comments.

So, yes, OracleLobHandler solves the problem. But in fact we are not forced to use deprecated class. In the OracleLobHandler documentation I found

Deprecated. in favor of DefaultLobHandler for the Oracle 10g driver and higher. Consider using the 10g/11g driver even against an Oracle 9i database! DefaultLobHandler.setCreateTemporaryLob(boolean) is the direct equivalent of this OracleLobHandler's implementation strategy, just using standard JDBC 4.0 API. That said, in most cases, regular DefaultLobHandler setup will work fine as well.

I tested it and it works.

But I had another problem using SqlLobValue together with OracleTypes.BLOB in PreparedStatementSetter (it is described here ClassCastException: SqlLobValue cannot be cast to oracle.sql.BLOB using PreparedStatementSetter)

My final working code is as follow:

public void saveThumbnails(List<Thumbnail> fileList) throws SQLException, IOException {

    BatchPreparedStatementSetter b = new BatchPreparedStatementSetter() {
        @Override
        public void setValues(PreparedStatement ps, int i) throws SQLException {
            Thumbnail thumbnail = fileList.get(i);
            byte[] thumbnailBytes = thumbnail.getThumbnail();
            ps.setObject(1, thumbnail.getFileCId(), OracleTypes.NUMBER);
            ps.setObject(2, thumbnail.getType().toString(), OracleTypes.VARCHAR);
            DefaultLobHandler lobHandler = new DefaultLobHandler();
            lobHandler.setCreateTemporaryLob(true);
            lobHandler.getLobCreator().setBlobAsBytes(ps, 3, thumbnailBytes);
        }

        @Override
        public int getBatchSize() {
            return fileList.size();
        }
    };
    jdbcTemplate.batchUpdate(getSaveThumbnailSql(), b);
}

private String getSaveThumbnailSql() {
    // @formatter:off
    String sql = ""
            + "MERGE INTO file_thumbnails "
            + "     USING (SELECT ? as file_c_id, ? as thumbnail_type, ? AS thumbnail_image FROM DUAL) tmp "
            + "        ON (file_thumbnails.file_c_id = tmp.file_c_id AND "
            + "            file_thumbnails.thumbnail_type = tmp.thumbnail_type) "
            + "      WHEN MATCHED THEN "
            + "        UPDATE "
            + "           SET thumbnail_image = tmp.thumbnail_image"
            + "              ,thumbnail_date = SYSDATE "
            + "      WHEN NOT MATCHED THEN "
            + "        INSERT (c_id, file_c_id, thumbnail_type, thumbnail_image, thumbnail_date) "
            + "        VALUES (cedar_c_id_seq.nextval, tmp.file_c_id, tmp.thumbnail_type, tmp.thumbnail_image , SYSDATE)";
    //@formatter:on
    return sql;
}

I'm not really a Spring framework expert but I could reproduce and somewhat debug your problem. It has to do with the DefaultLobHandler that you pass one which does seem to get bound as a LONG data type rather than a BLOB by error.

Here is a simplified test case of your above call with a batch size of one:

String sql = "MERGE INTO file_thumbnails "
        + "     USING (SELECT ? as file_c_id, ? as thumbnail_type, ? as thumbnail_image FROM DUAL) tmp "
        + "        ON (file_thumbnails.file_c_id = tmp.file_c_id AND "
        + "            file_thumbnails.thumbnail_type = tmp.thumbnail_type) "
        + "      WHEN MATCHED THEN "
        + "        UPDATE "
        + "           SET thumbnail_image = tmp.thumbnail_image "
        + "              ,thumbnail_date = SYSDATE "
        + "      WHEN NOT MATCHED THEN "
        + "        INSERT (file_c_id, thumbnail_type, thumbnail_image, thumbnail_date) "
        + "        VALUES (tmp.file_c_id, tmp.thumbnail_type, tmp.thumbnail_image, SYSDATE)";

byte[] content = Files.readAllBytes(Paths.get("/Users/gvenzl/Downloads/image1.JPG"));
ByteArrayInputStream bin = new ByteArrayInputStream(content);
SqlLobValue sqlLobValue = new SqlLobValue(bin, content.length, new DefaultLobHandler());
List<Object []> x =  new ArrayList<Object []>();
x.add(new Object [] { 1, "Test", sqlLobValue});

jdbcTemplate.batchUpdate(sql, x, new int[] { OracleTypes.NUMBER, OracleTypes.VARCHAR, OracleTypes.BLOB});

System.out.print("Successful!");

I'm reading an image, then create a single item array and execute that the same way you have and error:

Exception in thread "main" org.springframework.jdbc.UncategorizedSQLException: PreparedStatementCallback; uncategorized SQLException for SQL [MERGE INTO file_thumbnails      USING (SELECT ? as file_c_id, ? as thumbnail_type, ? as thumbnail_image FROM DUAL) tmp         ON (file_thumbnails.file_c_id = tmp.file_c_id AND             file_thumbnails.thumbnail_type = tmp.thumbnail_type)       WHEN MATCHED THEN         UPDATE            SET thumbnail_image = tmp.thumbnail_image               ,thumbnail_date = SYSDATE       WHEN NOT MATCHED THEN         INSERT (file_c_id, thumbnail_type, thumbnail_image, thumbnail_date)         VALUES (tmp.file_c_id, tmp.thumbnail_type, tmp.thumbnail_image, SYSDATE)]; SQL state [72000]; error code [1461]; ORA-01461: can bind a LONG value only for insert into a LONG column
; nested exception is java.sql.BatchUpdateException: ORA-01461: can bind a LONG value only for insert into a LONG column

Now I'm changing the LOB handler from DefaultLobHandler to the deprecated OracleLobHandler:

byte[] content = Files.readAllBytes(Paths.get("/Users/gvenzl/Downloads/image1.JPG"));
ByteArrayInputStream bin = new ByteArrayInputStream(content);
SqlLobValue sqlLobValue = new SqlLobValue(bin, content.length, new OracleLobHandler());
List<Object []> x =  new ArrayList<Object []>();
x.add(new Object [] { 1, "Test", sqlLobValue});

jdbcTemplate.batchUpdate(sql, x, new int[] { OracleTypes.NUMBER, OracleTypes.VARCHAR, OracleTypes.BLOB});

System.out.print("Successful!");

And my out is:

Successful!

Debugging through it, the difference that I could see was that the OracleLobHandler uses the ps.setBlob() method while the DefaultLobHandler uses ps.setBinaryStream() which seems to result into the variable being bound as a LONG rather than a BLOB. Hope this helps!

标签
Spring
Oracle
blob
jdbctemplate
sql-merge
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