java-spring的JdbcTempldate对oracle 的CLob字段进行读和写

相关介绍-

Spring 让 LOB 数据操作变得简单易行（http://www.ibm.com/developerworks/cn/java/j-lo-spring-lob/）

具体代码：

Blob操作也类似Clob，也是通过LobHandler 类的方法进行操作。

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.AbstractLobCreatingPreparedStatementCallback;
import org.springframework.jdbc.support.lob.DefaultLobHandler;
import org.springframework.jdbc.support.lob.LobCreator;
import org.springframework.jdbc.support.lob.LobHandler;
import org.springframework.stereotype.Repository;

import com.commom.model.PageBean;

/**
* 类：ReportTemplateDaoImpl.java
* 时间：2016-1-8
* 说明：模板
*/
@Repository
public class ReportTemplateDaoImpl extends BaseDao
{

/**
* 根据条件获取模板的信息
* @param queryMap：查询条件
* @return
*/
public List<Map<String, Object>> queryReportTemplate(Map<String,Object> filterMap)
{
return execConditonSql(filterMap,false);
}
/**
* 统计模板总记录数
* @param queryMap：查询条件
* @return
*/
public int countReportTemplate(Map<String,Object> filterMap)
{
List<Map<String, Object>> retObjMapList =  execConditonSql(filterMap, true);
return Integer.valueOf(retObjMapList.get(0).get("count").toString());
}

/**
* 根据条件查询模板信息
* @param filterMap
* @return
*/
public  List<Map<String,Object>> execConditonSql(Map<String,Object> filterMap,boolean isCount)
{

StringBuffer sql;

if(isCount)
{
//查数据条数
sql = new StringBuffer(" select count(*) as count from TEMPLATE_TABLE where 1=1 ");

}else
{
//查数据信息
sql = new StringBuffer(" select * from TEMPLATE_TABLE where 1=1 ");
}

if(filterMap != null )
{
if(filterMap.containsKey("title"))
{
sql.append("and title like '%"+ filterMap.get("title") +"%'");

}

if(filterMap.containsKey("label"))
{
sql.append("and label like '%"+ filterMap.get("label") +"%'");

}

if(filterMap.containsKey("type"))
{
sql.append("and type ="+Integer.valueOf(filterMap.get("type").toString()));
}
}

//分页
String execSql = sql.toString();
if(!isCount && filterMap.containsKey("pageBean")){
PageBean pb = (PageBean)filterMap.get("pageBean");
execSql = getPageSql(execSql, pb.getBeginRowNum(), pb.getEndRowNum());
}

if(!isCount)
{
//求表中数据的信息

final LobHandler lobHandle = new DefaultLobHandler();

@SuppressWarnings({ "unchecked", "rawtypes" })
List<Map<String,Object>> resultList =  this.jdbcTemplate.query(execSql,new RowMapper()
{
@Override
public Object mapRow(ResultSet rs, int rowsNum) throws SQLException
{
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();

while(rs.next())
{
long id = rs.getLong("id");
String title = rs.getString("title");
String label = rs.getString("label");
int type = rs.getInt("type");

//thumbnail_id 字段要根据ID去获得缩略图的模板 待处理
int thumbnail_id = rs.getInt("thumbnail_id");

String template_content = lobHandle.getClobAsString(rs, "template_content");

Map<String,Object> map = new HashMap<String, Object>();
map.put("id", id);
map.put("title", title);
map.put("label", label);
map.put("type", type);

//thumbnail_id 字段要根据ID去获得缩略图的模板 待处理
map.put("thumbnail_id", thumbnail_id);

map.put("template_content", template_content);

list.add(map);
}

rs.close();

return list;
}
});

return resultList;

}else
{
//求表中总的记录数
return this.jdbcTemplate.queryForList(execSql);
}

}

/**
* 根据ID查找模板信息
* @param id
* @return
*/
public Map<String,Object> getReportTemplateById(int id)
{

String sql ="select id,title,label,type,thumbnail_id,template_content from TEMPLATE_TABLE  where id =?";

final LobHandler lobHandle = new DefaultLobHandler();

@SuppressWarnings({ "unchecked", "rawtypes" })
Map<String,Object> resultMap = (Map<String, Object>) this.jdbcTemplate.query(sql, new Object[]{id},new RowMapper()
{

@Override
public Object mapRow(ResultSet rs, int rowsNum) throws SQLException
{
long id = rs.getLong(1);
String title = rs.getString("title");
String label = rs.getString("label");
int type = rs.getInt("type");

//thumbnail_id 字段要根据ID去获得缩略图的模板 待处理
int thumbnail_id = rs.getInt("thumbnail_id");

String template_content = lobHandle.getClobAsString(rs, "template_content");

Map<String,Object> map = new HashMap<String, Object>();
map.put("id", id);
map.put("title", title);
map.put("label", label);
map.put("type", type);

//thumbnail_id 字段要根据ID去获得缩略图的模板 待处理
map.put("thumbnail_id", thumbnail_id);

map.put("template_content", template_content);

return map;
}

});

return resultMap;
}

/**
* 添加模板信息
* @param filterMap
* @return
* @throws IOException
*/
public boolean addReportTemplateInfo(final Map<String,Object> filterMap)
{
/*
* 通过PreparedStatement预处理语句向SQL语句中依次添加各变量
*/
int affectNum = 0;

if(filterMap.size() > 0)
{
final String title = filterMap.get("title").toString();
final String label = filterMap.get("label").toString();
final Integer type = Integer.valueOf(filterMap.get("type").toString());

//判断是否包含thumbnail_id 字段
String strThumbnail_id ="0";
if(filterMap.containsKey("thumbnail_id"))
{
strThumbnail_id = filterMap.get("thumbnail_id").toString();
}

final Integer thumbnail_id = Integer.valueOf(strThumbnail_id);

final String template_content =filterMap.get("template_content").toString();

String sql = " INSERT INTO TEMPLATE_TABLE(id,title,label,type,thumbnail_id,template_content)"
+ " VALUES(TEMPLATE_TABLE_id_seq.nextval,?,?,?,?,?)";

LobHandler handle = new DefaultLobHandler();

affectNum =  this.jdbcTemplate.update(
sql,
new AbstractLobCreatingPreparedStatementCallback(
handle) {
@Override
protected void setValues(PreparedStatement pStat, LobCreator lobCreator)
throws SQLException, DataAccessException
{

pStat.setString(1,title);
pStat.setString(2,label);
pStat.setInt(3, type);
//判断是否包含缩略图ID,没有插入空内容
if(filterMap.containsKey("thumbnail_id"))
{
pStat.setInt(4, thumbnail_id);
}else
{
pStat.setString(4,"");
}
lobCreator.setClobAsString(pStat,5,template_content );

}
});
}
return affectNum > 0;

}

/**
* 更新模板信息
* @param filterMap
* @return
*/
public  boolean updateReportTemplateInfo(final Map<String,Object> filterMap)
{
int affectNum = 0;

if(filterMap.size() > 0)
{
final String title = filterMap.get("title").toString();
final String label = filterMap.get("label").toString();
final Integer type = Integer.valueOf(filterMap.get("type").toString());

//判断是否包含thumbnail_id 字段
String strThumbnail_id ="0";
if(filterMap.containsKey("thumbnail_id"))
{
strThumbnail_id = filterMap.get("thumbnail_id").toString();
}

final Integer thumbnail_id = Integer.valueOf(strThumbnail_id);

final String template_content =filterMap.get("template_content").toString();

final Integer id = Integer.valueOf(filterMap.get("id").toString());

String sql ="update TEMPLATE_TABLE set title =?,label =?,type =?,thumbnail_id =?,template_content=? where id =?";

LobHandler handle = new DefaultLobHandler();

affectNum =  this.jdbcTemplate.execute(
sql,
new AbstractLobCreatingPreparedStatementCallback(
handle) {
@Override
protected void setValues(PreparedStatement pStat, LobCreator lobCreator)
throws SQLException, DataAccessException
{
pStat.setString(1,title);
pStat.setString(2,label);
pStat.setInt(3, type);
//判断是否包含缩略图ID,没有插入空内容
if(filterMap.containsKey("thumbnail_id"))
{
pStat.setInt(4, thumbnail_id);
}else
{
pStat.setString(4,"");
}
lobCreator.setClobAsString(pStat,5,template_content );

pStat.setInt(6, id);
}
});
}
return affectNum > 0;

}

/**
* @param id
* @return
* 删除模板信息
*/
public boolean deleteReportTemplateInfo(int id)
{
String sql ="delete from TEMPLATE_TABLE where id =?";

return this.jdbcTemplate.update(sql,new Object[]{id})>0;
}

}

相关查考文章：

利用spring的jdbcTemplate处理blob、clob

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：

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"
class="org.springframework.jdbc.support.nativejdbc.CommonsDbcpNativeJdbcExtractor"
lazy-init="true" />
<bean id="oracleLobHandler"
class="org.springframework.jdbc.support.lob.OracleLobHandler"
lazy-init="true">
<property name="nativeJdbcExtractor" ref="nativeJdbcExtractor" />
</bean>
<bean id="dao" abstract="true">
<property name="jdbcTemplate" ref="jdbcTemplate" />
</bean>
<bean id="postDao" parent="dao"
class="com.baobaotao.dao.jdbc.PostJdbcDao">
<property name="lobHandler" ref="oracleLobHandler" />
</bean>

Oracle 10g或其他数据库如下设置：

<bean id="defaultLobHandler"
class="org.springframework.jdbc.support.lob.DefaultLobHandler"
lazy-init="true" />
<bean id="dao" abstract="true">
<property name="jdbcTemplate" ref="jdbcTemplate" />
</bean>
<bean id="postDao" parent="dao"
class="com.baobaotao.dao.jdbc.PostJdbcDao">
<property name="lobHandler" 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;
}
});
}