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https://issues.apache.org/jira/browse/DERBY-5090?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kristian Waagan reassigned DERBY-5090:
--------------------------------------
Assignee: Kristian Waagan
> Retrieving BLOB fields sometimes fails
> --------------------------------------
>
> Key: DERBY-5090
> URL: https://issues.apache.org/jira/browse/DERBY-5090
> Project: Derby
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 10.7.1.1
> Environment: JDBC derby embedded driver
> Reporter: Unai Vivi
> Assignee: Kristian Waagan
> Labels: BLOB, exception, null, read
> Attachments: Derby5090.java, Derby5090_2.java, Derby5090_3.java
>
>
> This is my first issue report, so please be understanding if I'm posting the
> wrong thing, in the wrong place or in the wrong way. I just want to help. :)
> While iterating through a ResultSet, when accessing a BLOB field to read its
> contents via an InputStream, I noticed that:
> - if the current ResultSet's has been "warmed up" by retrieving another
> column first, everything it's fine;
> - if, on the other hand, you first-thing access the BLOB (and read other
> columns later), then upon reading the first byte out the InputStream bound to
> the BLOB field (ResultSet.getBinaryStream("col_name")) an IOException is
> thrown (and IOException's getMessage() method returns null).
> Following is an example, taken from a real application. The two code segments
> only differ in the fact that a SMALLINT & VARCHAR read is done before/after
> the BLOB read.
> --Working snippet--
> [...]
> icRelPath[i] = "imm" + File.separator + "ic" + "_" +
> rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
> AutoCloseInputStream acis = new
> AutoCloseInputStream(rs.getBinaryStream("ic" + i));
> if (rs.wasNull())
> icRelPath[i] = null;
> else
> {
> //icRelPath[i] = "imm" + File.separator + "ic" + "_"
> + rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
> BufferedInputStream bis = new
> BufferedInputStream(acis);
> int b = bis.read();//READS FINE
> [...]
> --Broken snippet--
> [...]
> //icRelPath[i] = "imm" + File.separator + "ic" + "_" +
> rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
> AutoCloseInputStream acis = new
> AutoCloseInputStream(rs.getBinaryStream("ic" + i));
> if (rs.wasNull())
> icRelPath[i] = null;
> else
> {
> icRelPath[i] = "imm" + File.separator + "ic" + "_" +
> rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
> BufferedInputStream bis = new
> BufferedInputStream(acis);
> int b = bis.read();//THROWS IOException WITH A null
> ERROR MESSAGE STRING
> [...]
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