oracle中读写blob字段的问题

3、替?BLOB?像（?原BLOB?像清除，?成一?全新的BLOB?像）

public static void blobReplace(String infile) throws Exception

{

/* ?定不自?提交 */

boolean defaultCommit = conn.getAutoCommit();

conn.setAutoCommit(false);

try {

/* 清空原BLOB?像 */

stmt.executeUpdate("UPDATE TEST_BLOB SET BLOBCOL=EMPTY_BLOB() WHERE ID='222'");

/* 查?此BLOB?象??定 */

ResultSet rs = stmt.executeQuery("SELECT BLOBCOL FROM TEST_BLOB WHERE ID='222' FOR UPDATE");

while (rs.next()) {

/* 取出此BLOB?像 */

oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("BLOBCOL");

/* 向BLOB?像中?入?? */

BufferedOutputStream out = new BufferedOutputStream(blob.getBinaryOutputStream());

BufferedInputStream in = new BufferedInputStream(new FileInputStream(infile));

int c;

while ((c=in.read())!=-1) {

out.write(c);

}

in.close();

out.close();

}

/* 正式提交 */

conn.commit();

} catch (Exception ex) {

/* 出?回? */

conn.rollback();

throw ex;

}

/* 恢?原提交?? */

conn.setAutoCommit(defaultCommit);

}

4、BLOB?像?取

public static void blobRead(String outfile) throws Exception

{

/* ?定不自?提交 */

boolean defaultCommit = conn.getAutoCommit();

conn.setAutoCommit(false);

try {

/* 查?BLOB?像 */

ResultSet rs = stmt.executeQuery("SELECT BLOBCOL FROM TEST_BLOB WHERE ID='222'");

while (rs.next()) {

/* 取出此BLOB?像 */

oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("BLOBCOL");

/* 以二?制形式?出 */

BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(outfile));

BufferedInputStream in = new BufferedInputStream(blob.getBinaryStream());

int c;

while ((c=in.read())!=-1) {

out.write(c);

}

in.close();

out.close();

}

/* 正式提交 */

conn.commit();

} catch (Exception ex) {

/* 出?回? */

conn.rollback();

throw ex;

}

/* 恢?原提交?? */

conn.setAutoCommit(defaultCommit);

}

?察上述程序?LOB?型字段的存取，我?可以看出，?之其它?型字段，有下面???著不同的特?：

一是必?取消自?提交。
 

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