java - Read Blob from PL/SQL through Spring

I am trying to retrieve a Blob value thorugh PL/SQL, Spring and JDBC.

Here is my PL/SQL

function GETBLOB(pjobid in number)
RETURN bobrecCur
is
vbobrecCur bobrecCur;
begin
   OPEN vbobrecCur FOR
   SELECT jobid, filecontent
   FROM TESTBULKJOBDATAFILE
   WHERE jobid = pjobid;
   RETURN vbobrecCur;
end GETBLOB

And my Java code is

this.getDataJdbcCall =
            new SimpleJdbcCall( this.jdbcTemplate )
                    .withFunctionName(  SQL_READ_DATA )
                    .withoutProcedureColumnMetaDataAccess()
                    .declareParameters(
                            new SqlOutParameter( "abc", OracleTypes.CURSOR ),
                            new SqlParameter( "pjobid", OracleTypes.INTEGER )
                    );

Map input = new HashMap();
    input.put( "pjobid", 99999 );

    ResultSet result = this.getDataJdbcCall.executeFunction(ResultSet.class , input );
    DefaultLobHandler lob =  new DefaultLobHandler();
    InputStream is = lob.getBlobAsBinaryStream( result, 1 );

I am getting the following exception.. basically saying that Resultset is null.

Exception in thread "main" java.lang.NullPointerException at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:91) at org.springframework.jdbc.core.JdbcTemplate.processResultSet(JdbcTemplate.java:1120) at org.springframework.jdbc.core.JdbcTemplate.extractOutputParameters(JdbcTemplate.java:1089) at org.springframework.jdbc.core.JdbcTemplate$5.doInCallableStatement(JdbcTemplate.java:996) at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:935) at org.springframework.jdbc.core.JdbcTemplate.call(JdbcTemplate.java:984) at org.springframework.jdbc.core.simple.AbstractJdbcCall.executeCallInternal(AbstractJdbcCall.java:364) at org.springframework.jdbc.core.simple.AbstractJdbcCall.doExecute(AbstractJdbcCall.java:349) at org.springframework.jdbc.core.simple.SimpleJdbcCall.executeFunction(SimpleJdbcCall.java:137)

I went through this question which should work for me. But I think the way I am using OracleLobHandler is not right.

Can anybody shed any light on where I am going wrong?

2 Answers

  1. Leander- Reply

    2019-11-14

    Never mind, I figured out how to do it with a BLOB return type rather than a Cursor.

    CREATE OR REPLACE function GETDATA(pjobid in number)
    RETURN BLOB
    is
    begin
        SELECT filecontent into pblob
        from TESTDATA
        where jobid = pjobid;
        return pblob;
    end;
    

    And in Java I did this

    this.getDataJdbcCall =
                new SimpleJdbcCall( this.jdbcTemplate )
                        .withFunctionName( SQL_READ_DATA )
                        .withoutProcedureColumnMetaDataAccess()
                        .declareParameters( new SqlOutParameter( "abc", OracleTypes.BLOB ),
                                new SqlParameter( "pjobid", OracleTypes.INTEGER ) );
    
    
    
        System.out.println( "Reading data" );
    
        Map input = new HashMap();
        input.put( "pjobid", 99999 );
    
        Blob result = this.getDataJdbcCall.executeFunction( Blob.class, input );
    
        InputStream is = result.getBinaryStream();
    
        byte[] b = new byte[1000];
        while ( true ) {
            if ( is.read( b ) == -1 )
                break;
    
            System.out.print( new String( b ) );
        }
    
  2. Lee- Reply

    2019-11-14

    package test;
    
    import java.util.List;
    import java.util.Map;
    
    import org.springframework.jdbc.core.JdbcTemplate;
    import org.springframework.jdbc.datasource.DriverManagerDataSource;
    
    public class SelectBlobBug {
        public static void main(String[] args) {
            JdbcTemplate jdbcTemplate = new JdbcTemplate(new DriverManagerDataSource("jdbc:derby:test-db;create=true"));
    
            jdbcTemplate.execute("DROP TABLE blob_test");
            jdbcTemplate.execute("CREATE TABLE blob_test (DATA BLOB NOT NULL)");
            byte[] binaryData = new byte[32700];
            for (int i = 0; i < binaryData.length; i++) {
                binaryData[i] = (byte) i;
            }
            jdbcTemplate.update("INSERT INTO blob_test VALUES (?)", binaryData);
    
            List<Map<String, Object>> result = jdbcTemplate.queryForList("SELECT * FROM blob_test");
    
            System.out.println(((byte[]) result.get(0).get("DATA")).length); // should be 32700
        }
    }
    

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