Example usage for java.sql Blob truncate

Introduction

In this page you can find the example usage for java.sql Blob truncate.

Prototype

void truncate(long len) throws SQLException;

Source Link

Document

Truncates the BLOB value that this Blob object represents to be len bytes in length.

Usage

From source file:com.runwaysdk.dataaccess.database.general.Oracle.java

/**
 * Truncates a blob by the specified length.
 *
 * @param table//  w ww  .j  av a 2  s  .  c  o m
 * @param columnName
 * @param id
 * @param length
 */
public void truncateBlob(String table, String columnName, String id, long length, Connection conn) {
    PreparedStatement prepared = null;
    Statement statement = null;
    ResultSet resultSet = null;
    try {
        // get the blob
        statement = conn.createStatement();
        String select = "SELECT " + columnName + " FROM " + table + " WHERE " + EntityDAOIF.ID_COLUMN + " = '"
                + id + "' FOR UPDATE";
        String update = "UPDATE " + table + " SET " + columnName + " = " + "? WHERE " + EntityDAOIF.ID_COLUMN
                + " = '" + id + "'";
        resultSet = statement.executeQuery(select);
        boolean resultSetFound = resultSet.next();
        if (!resultSetFound) {
            return;
        }

        Blob blob = resultSet.getBlob(columnName);

        // null check
        if (blob != null) {
            blob.truncate(length);

            // modify the blob
            if (conn.getMetaData().locatorsUpdateCopy()) {
                // The current database needs to be manually updated (it doesn't
                // support auto blob updates)
                prepared = conn.prepareStatement(update);
                prepared.setBlob(1, blob);
                prepared.executeUpdate();
            }
        }
    } catch (SQLException e) {
        this.throwDatabaseException(e);
    } finally {
        try {
            if (resultSet != null)
                resultSet.close();
            if (statement != null)
                statement.close();
            if (prepared != null)
                prepared.close();
        } catch (SQLException e) {
            this.throwDatabaseException(e);
        }
    }
}

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From source file:org.etudes.jforum.dao.oracle.OracleUtils.java

/**
 * The query should look like://from   w ww.  j  a  v  a  2  s  .c  o  m
 * 
 * SELECT blob_field from any_table WHERE id = ? FOR UPDATE
 * 
 * BUT KEEP IN MIND:
 * 
 * When you insert record in previous step, it should go with empty_blob() like:
 * 
 * INSERT INTO jforum_posts_text ( post_text ) VALUES (EMPTY_BLOB())
 * 
 * @param query
 * @param idForQuery
 * @param value
 * @throws IOException
 * @throws SQLException
 */
public static void writeBlobUTF16BinaryStream(String query, int idForQuery, String value)
        throws IOException, SQLException {
    PreparedStatement p = JForum.getConnection().prepareStatement(query);
    p.setInt(1, idForQuery);

    ResultSet rs = p.executeQuery();
    rs.next();
    Blob postText = rs.getBlob(1);

    //wipe out the Blob contents 
    postText.truncate(0);

    if (logger.isDebugEnabled())
        logger.debug("post test is a " + postText.getClass().getName());

    // OutputStream blobWriter = ((oracle.sql.BLOB)postText).setBinaryStream(0L);
    OutputStream blobWriter = postText.setBinaryStream(0L);
    blobWriter.write(value.getBytes("UTF-16"));

    blobWriter.flush();
    blobWriter.close();
    rs.close();
    p.close();
}

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From source file:org.opencms.db.oracle.CmsUserDriver.java

/**
 * Generates an Output stream that writes to a blob, also truncating the existing blob if required.<p>
 * /*from ww  w.j  a  v  a 2 s .c  o m*/
 * Apparently Oracle requires some non-standard handling here.<p>
 * 
 * @param res the result set where the blob is located in 
 * @param name the name of the database column where the blob is located
 * @return an Output stream from a blob
 * @throws SQLException if something goes wring
 */
@SuppressWarnings("deprecation")
public static OutputStream getOutputStreamFromBlob(ResultSet res, String name) throws SQLException {

    // TODO: perform blob check only once and store Oracle version in a static private member 
    // TODO: best do this during system startup / db init phase once
    Blob blob = res.getBlob(name);
    try {
        // jdbc standard
        blob.truncate(0);
        return blob.setBinaryStream(0L);
    } catch (SQLException e) {
        // oracle 9 & 8 (if using the same jdbc driver as provided by oracle9: ojdbc14.jar)
        ((oracle.sql.BLOB) blob).trim(0);
        return ((oracle.sql.BLOB) blob).getBinaryOutputStream();
    }
}

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From source file:org.openehealth.ipf.commons.flow.hibernate.HibernateUtils.java

/**
 * Writes a byte array to a {@link Blob}.
 * //from w  w w. ja va2 s  . c om
 * @param bytes
 *            byte array.
 * @param blob
 *            an initialized {@link Blob}.
 * @return the {@link Blob} instance passed as <code>blob</code> argument.
 * @throws SQLException
 */
public static Blob writeToBlob(byte[] bytes, Blob blob) throws SQLException {
    if (/*blob != null*/ false) { // not supported
        blob.setBytes(0, bytes);
        blob.truncate(bytes.length);
    } else {
        blob = Hibernate.createBlob(bytes);
    }
    return blob;
}

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