Mybatis/Ibatis，数据库操作的返回值
insert，返回值是：新插入行的主键（primary key）；需要包含<selectKey>语句，才会返回主键，否则返回值为null。update/delete，返回值是：更新或删除的行数；无需指明resultClass；但如果有约束异常而删除失败，只能去捕捉异常。
queryForObject，返回的是：一个实例对象或null；需要包含<select>语句，并且指明resultMap；
queryForList，返回的是：实例对象的列表；需要包含<select>语句，并且指明resultMap；
我的配置文件如下（desktop_common_sqlMap.xml）：
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<typeAlias alias="UnlockTagInfo" type="com.desktop.common.bean.UnlockTagInfo" />
<resultMap class="UnlockTagInfo" id="UnlockTagInfoResult">
<result column="id" property="id" jdbcType="INTEGER" />
<result column="name" property="name" jdbcType="VARCHAR" />
<result column="description" property="description" jdbcType="VARCHAR" />
<result column="priority" property="priority" jdbcType="INTEGER" />
</resultMap>
<insert id="insertUnlockTagInfo" parameterClass="map">
<selectKey resultClass="int" keyProperty="id">
select
nextval('desktop_unlock_tag_id_seq') as id
</selectKey>
insert into
desktop_unlock_tag(id,name,description,priority)
values(#id:INTEGER#,#name:VARCHAR#,#description:VARCHAR#,#priority:INTEGER#)
</insert>
<update id="updateUnlockTagInfo" parameterClass="map">
update
desktop_unlock_tag
set modify_time=now(),priority=#priority:INTEGER#,
name=#name:VARCHAR#,description=#description:VARCHAR#
where
id=#id:INTEGER#
</update>
<delete id="deleteUnlockTagInfo" parameterClass="int">
delete from
desktop_unlock_tag
where id=#value:INTEGER#
</delete>
<select id="countUnlockTagInfo" resultClass="int">
select count(*)
from
desktop_unlock_tag
</select>
<sql id="selectUnlockTagInfo">
select
id,name,description,priority
from
desktop_unlock_tag
</sql>
<select id="findUnlockTagInfoById" parameterClass="int"
resultMap="UnlockTagInfoResult">
<include refid="selectUnlockTagInfo" />
where id=#id:INTEGER#
</select>
<select id="listUnlockTagInfo" parameterClass="map"
resultMap="UnlockTagInfoResult">
<include refid="selectUnlockTagInfo" />
order by
modify_time desc limit #size:INTEGER#
offset #start:INTEGER#
</select>
我的DAO源码如下：
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public class UnlockTagDaoImpl extends SqlMapClientDaoSupport implements
UnlockTagDao {
@Override
public Integer addItem(String name, String desc, Integer priority) {
SqlMapClientTemplate template = this.getSqlMapClientTemplate();
Map<String, Object> args = new HashMap<String, Object>();
args.put("name", name);
args.put("description", desc);
args.put("priority", priority);
Object key = template.insert("DesktopCommon.insertUnlockTagInfo", args);
return (Integer) key;
}
@Override
public boolean updateItem(Integer id, String name, String description,
Integer priority) {
SqlMapClientTemplate template = this.getSqlMapClientTemplate();
Map<String, Object> args = new HashMap<String, Object>();
args.put("id", id);
args.put("name", name);
args.put("description", description);
args.put("priority", priority);
try {
int c = template.update("DesktopCommon.updateUnlockTagInfo", args);
if (c > 0) {
return true;
}
return false;
} catch (Exception e) {
return false;
}
}
@Override
public boolean deleteItem(Integer id) {
SqlMapClientTemplate template = this.getSqlMapClientTemplate();
try {
int c = template.delete("DesktopCommon.deleteUnlockTagInfo", id);
if (c > 0) {
return true;
}
return false;
} catch (Exception e) {
return false;
}
}
@Override
public UnlockTagInfo findItemById(Integer id) {
SqlMapClientTemplate template = this.getSqlMapClientTemplate();
UnlockTagInfo item = (UnlockTagInfo) template.queryForObject(
"DesktopCommon.findUnlockTagInfoById", id);
return item;
}
@Override
public PagedList<UnlockTagInfo> listAll(Integer nStart, Integer nSize,
boolean bCountTotal) {
SqlMapClientTemplate template = this.getSqlMapClientTemplate();
PagedList<UnlockTagInfo> result = new PagedList<UnlockTagInfo>();
if (bCountTotal) {
int total = (Integer) template
.queryForObject("DesktopCommon.countUnlockTagInfo");
result.setTotal(total);
}
Map<String, Integer> args = new HashMap<String, Integer>();
args.put("start", nStart);
args.put("size", nSize);
@SuppressWarnings("unchecked")
List<UnlockTagInfo> items = template.queryForList(
"DesktopCommon.listUnlockTagInfo", args);
result.setData(items);
return result;
}
}
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