Examples with Blob java.sql.Blob used on opensource projects

Example 96 with Blob

use of java.sql.Blob in project derby by apache.

the class BlobAccessTest method testFetchLargeBlobs.

/**
 * Fetches a number of Blobs using a rather large read buffer with
 * {@code getBinaryStream}.
 */
public void testFetchLargeBlobs() throws IOException, SQLException {
    PreparedStatement ps = prepareStatement("select dBlob, length from largeBlobs");
    ResultSet rs = ps.executeQuery();
    // 16 KB
    byte[] byteBuf = new byte[16 * 1024];
    while (rs.next()) {
        Blob Blob = rs.getBlob(1);
        InputStream content = Blob.getBinaryStream();
        long remaining = rs.getInt(2);
        while (remaining > 0) {
            remaining -= content.read(byteBuf);
        }
        content.close();
    }
    rs.close();
}

Example 97 with Blob

use of java.sql.Blob in project derby by apache.

the class BlobAccessTest method testFetchSmallBlobs.

/**
 * Fetches a number of small Blobs, getting the content using getBytes.
 * <p>
 * The exact length of the Blob is used when getting the bytes.
 */
public void testFetchSmallBlobs() throws SQLException {
    PreparedStatement ps = prepareStatement("select dBlob, length from smallBlobs");
    ResultSet rs = ps.executeQuery();
    while (rs.next()) {
        Blob Blob = rs.getBlob(1);
        int blobLength = rs.getInt(2);
        byte[] content = Blob.getBytes(1, blobLength);
    }
    rs.close();
}

Example 98 with Blob

use of java.sql.Blob in project derby by apache.

the class BlobAccessTest method fetchBlobPieceByPiece.

/**
 * Fetches a "large" Blob piece by piece using getBytes.
 *
 * @param modifyBlob whether to modify the Blob before fetching it
 *      (determines the internal Derby Blob representation)
 */
private void fetchBlobPieceByPiece(boolean modifyBlob, int fetchMode) throws IOException, SQLException {
    // Select just one Blob.
    PreparedStatement ps = prepareStatement("select dBlob, length from largeBlobs where id = 4");
    ResultSet rs = ps.executeQuery();
    while (rs.next()) {
        Blob blob = rs.getBlob(1);
        long remaining = rs.getInt(2);
        if (modifyBlob) {
            // Modify the Blob to create a temporary copy in memory or on
            // disk (depends on the Blob size).
            long modifyStart = System.currentTimeMillis();
            blob.setBytes(++remaining, new byte[] { (byte) 'X' });
            println("Blob modification duration: " + (System.currentTimeMillis() - modifyStart) + " ms");
        }
        long pos = 1;
        int MAX_SIZE = 32676;
        switch(fetchMode) {
            case FETCH_GETBYTES:
                while (remaining > 0) {
                    byte[] bytes = blob.getBytes(pos, (int) Math.min(MAX_SIZE, remaining));
                    pos += bytes.length;
                    remaining -= bytes.length;
                }
                break;
            case FETCH_GETBINARYSTREAM:
                InputStream stream = blob.getBinaryStream();
                byte[] buf = new byte[MAX_SIZE];
                while (remaining > 0) {
                    int read = stream.read(buf);
                    pos += read;
                    remaining -= read;
                }
                stream.close();
                break;
            default:
                fail("Unknown fetch mode: " + fetchMode);
        }
    }
    rs.close();
}

Example 99 with Blob

use of java.sql.Blob in project derby by apache.

the class LOBLocatorReleaseTest method forwardOnlyTest.

private void forwardOnlyTest(String table) throws SQLException {
    final String sql = "select dBlob, dClob from " + table;
    getConnection().setAutoCommit(false);
    // Just loop through.
    Statement stmt = createStatement();
    ResultSet rs = stmt.executeQuery(sql);
    while (rs.next()) {
    // Just iterate through.
    }
    rs.close();
    // Loop through and get references to some of the LOBs.
    // When you get a LOB reference, the locator shuold only be freed on
    // explicit calls to free (requires Java SE 6) or commit/rollback.
    rs = stmt.executeQuery(sql);
    int index = 0;
    while (rs.next()) {
        if (index % 2 == 0) {
            Blob b = rs.getBlob(1);
            if (!rs.wasNull()) {
                b.length();
            }
        }
        if (index % 3 == 0) {
            Clob c = rs.getClob(2);
            if (!rs.wasNull()) {
                c.length();
            }
        }
        // Clear all LOB mappings after 10 rows.
        if (index == 9) {
            commit();
        }
        index++;
    }
    rs.close();
    stmt.close();
    // Close the statement after a few rows.
    stmt = createStatement();
    rs = stmt.executeQuery(sql);
    rs.next();
    rs.next();
    stmt.close();
    // The LOB mapping is cleared on a commit.
    commit();
    // Close the result set after a few rows and a rollback.
    stmt = createStatement();
    rs = stmt.executeQuery(sql);
    rs.next();
    rs.next();
    rollback();
    rs.close();
}

Example 100 with Blob

use of java.sql.Blob in project derby by apache.

the class BlobSetMethodsTest method testSetBytesLargeBlob.

/**
 * Tests large blob (more than 4k) to ensure LOBStreamControl uses file.
 */
public void testSetBytesLargeBlob() throws SQLException {
    Connection con = getConnection();
    con.setAutoCommit(false);
    PreparedStatement pstmt = con.prepareStatement("insert into " + "blobtest (id, data) values (?,?)");
    Blob blob = con.createBlob();
    byte[] data = new byte[BUFFER_SIZE];
    for (int i = 0; i < BUFFER_SIZE; i++) {
        data[i] = (byte) (i % 255);
    }
    // now add more than 4k so file get in use
    for (int i = 0; i < 5; i++) blob.setBytes(i * BUFFER_SIZE + 1, data);
    assertEquals(BUFFER_SIZE * 5, blob.length());
    // update blob in the middle
    byte[] data1 = new byte[UPDATE_SIZE];
    for (int i = 0; i < UPDATE_SIZE; i++) // just any value
    data1[i] = 120;
    blob.setBytes(BUFFER_SIZE + 1, data1);
    blob.setBytes(BUFFER_SIZE * 5 + 1, data1);
    assertEquals(5 * BUFFER_SIZE + UPDATE_SIZE, blob.length());
    // insert it into table
    pstmt.setInt(1, 3);
    pstmt.setBlob(2, blob);
    pstmt.executeUpdate();
    Statement stmt = con.createStatement();
    ResultSet rs = stmt.executeQuery("select data from blobtest where " + "id = 3");
    assertEquals(true, rs.next());
    blob = rs.getBlob(1);
    byte[] data2 = blob.getBytes(BUFFER_SIZE + 1, UPDATE_SIZE);
    assertEquals(5 * BUFFER_SIZE + UPDATE_SIZE, blob.length());
    for (int i = 0; i < UPDATE_SIZE; i++) assertEquals(data1[i], data2[i]);
    data2 = blob.getBytes(5 * BUFFER_SIZE + 1, UPDATE_SIZE);
    for (int i = 0; i < UPDATE_SIZE; i++) assertEquals(data1[i], data2[i]);
    // test truncate
    blob.truncate(BUFFER_SIZE);
    assertEquals("truncate failed", BUFFER_SIZE, blob.length());
    rs.close();
    con.commit();
    stmt.close();
    pstmt.close();
}