DB2\Oracle数据库对clob的处理
spring定义了一个以统一的方式操作各种数据库的Lob类型数据的LobCreator(保存的时候用),同时提供了一个LobHandler为操作二进制字段和大文本字段提供统一接口访问。
举例，例子里面的t_post表中post_text字段是CLOB类型,而post_attach是BLOG类型：

//db2数据库public class PostJdbcDao extends JdbcDaoSupport implements PostDao {private LobHandler lobHandler;private DataFieldMaxValueIncrementer incre;public LobHandler getLobHandler() {   return lobHandler;}public void setLobHandler(LobHandler lobHandler) {   this.lobHandler = lobHandler;}public void addPost(final Post post) {     String sql = " INSERT INTO t_post(post_id,user_id,post_text,post_attach)"     + " VALUES(?,?,?,?)";   getJdbcTemplate().execute(     sql,     new AbstractLobCreatingPreparedStatementCallback(       this.lobHandler) {      protected void setValues(PreparedStatement ps,        LobCreator lobCreator) throws SQLException {       ps.setInt(1, incre.nextIntValue());        ps.setInt(2, post.getUserId());        lobCreator.setClobAsString(ps, 3, post.getPostText());       lobCreator.setBlobAsBytes(ps, 4, post.getPostAttach());      }     });}}设置相对应的配置文件(Oracle 9i版本),Oracle的数据库最喜欢搞搞特别的东西啦：<bean id="nativeJdbcExtractor"   /><bean id="oracleLobHandler"   ref="nativeJdbcExtractor" /></bean><bean id="dao" abstract="true">   <property name="jdbcTemplate" ref="jdbcTemplate" /></bean><bean id="postDao" parent="dao"   ref="oracleLobHandler" /></bean>Oracle 10g或其他数据库如下设置：<bean id="defaultLobHandler"   /><bean id="dao" abstract="true">   <property name="jdbcTemplate" ref="jdbcTemplate" /></bean><bean id="postDao" parent="dao"   ref="defaultLobHandler" /></bean>读取BLOB/CLOB块,举例：public List getAttachs(final int userId){   String sql = "SELECT post_id,post_attach FROM t_post where user_id =? and post_attach is not null";   return getJdbcTemplate().query(       sql,new Object[] {userId},       new RowMapper() {        public Object mapRow(ResultSet rs, int rowNum) throws SQLException {        Post post = new Post();        int postId = rs.getInt(1);         byte[] attach = lobHandler.getBlobAsBytes(rs, 2);         post.setPostId(postId);         post.setPostAttach(attach);         return post;        }       });}