Mybatis/Ibatis，数据库操作的返回值

分类： Hibernate/Mybatis

该问题，我百度了下，根本没发现什么有价值的文章；还是看源代码（详见最后附录）中的注释，最有效了！

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;

}

}

关于ibatis的接口，参见其源码（com\ibatis\sqlmap\client\SqlMapExecutor.java）:

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/*

* Copyright 2004 Clinton Begin

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0
*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

package com.ibatis.sqlmap.client;

import com.ibatis.common.util.PaginatedList;

import com.ibatis.sqlmap.client.event.RowHandler;

import com.ibatis.sqlmap.engine.execution.BatchException;

import java.sql.SQLException;

import java.util.List;

import java.util.Map;

/**

* This interface declares all methods involved with executing statements

* and batches for an SQL Map.

*

* @see SqlMapSession

* @see SqlMapClient

*/

public interface SqlMapExecutor {

/**

* Executes a mapped SQL INSERT statement.

* Insert is a bit different from other update methods, as it

* provides facilities for returning the primary key of the

* newly inserted row (rather than the effected rows). This

* functionality is of course optional.

* <p/>

* The parameter object is generally used to supply the input

* data for the INSERT values.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @return The primary key of the newly inserted row. This might be automatically

* generated by the RDBMS, or selected from a sequence table or other source.

* @throws java.sql.SQLException If an error occurs.

*/

Object insert(String id, Object parameterObject) throws SQLException;

/**

* Executes a mapped SQL INSERT statement.

* Insert is a bit different from other update methods, as it

* provides facilities for returning the primary key of the

* newly inserted row (rather than the effected rows). This

* functionality is of course optional.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @return The primary key of the newly inserted row. This might be automatically

* generated by the RDBMS, or selected from a sequence table or other source.

* @throws java.sql.SQLException If an error occurs.

*/

Object insert(String id) throws SQLException;

/**

* Executes a mapped SQL UPDATE statement.

* Update can also be used for any other update statement type,

* such as inserts and deletes. Update returns the number of

* rows effected.

* <p/>

* The parameter object is generally used to supply the input

* data for the UPDATE values as well as the WHERE clause parameter(s).

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @return The number of rows effected.

* @throws java.sql.SQLException If an error occurs.

*/

int update(String id, Object parameterObject) throws SQLException;

/**

* Executes a mapped SQL UPDATE statement.

* Update can also be used for any other update statement type,

* such as inserts and deletes. Update returns the number of

* rows effected.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @return The number of rows effected.

* @throws java.sql.SQLException If an error occurs.

*/

int update(String id) throws SQLException;

/**

* Executes a mapped SQL DELETE statement.

* Delete returns the number of rows effected.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the DELETE statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @return The number of rows effected.

* @throws java.sql.SQLException If an error occurs.

*/

int delete(String id, Object parameterObject) throws SQLException;

/**

* Executes a mapped SQL DELETE statement.

* Delete returns the number of rows effected.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @return The number of rows effected.

* @throws java.sql.SQLException If an error occurs.

*/

int delete(String id) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a single object instance.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @return The single result object populated with the result set data,

* or null if no result was found

* @throws java.sql.SQLException If more than one result was found, or if any other error occurs.

*/

Object queryForObject(String id, Object parameterObject) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a single object instance.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @return The single result object populated with the result set data,

* or null if no result was found

* @throws java.sql.SQLException If more than one result was found, or if any other error occurs.

*/

Object queryForObject(String id) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* the supplied result object.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @param resultObject The result object instance that should be populated with result data.

* @return The single result object as supplied by the resultObject parameter, populated with the result set data,

* or null if no result was found

* @throws java.sql.SQLException If more than one result was found, or if any other error occurs.

*/

Object queryForObject(String id, Object parameterObject, Object resultObject) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @return A List of result objects.

* @throws java.sql.SQLException If an error occurs.

*/

List queryForList(String id, Object parameterObject) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @return A List of result objects.

* @throws java.sql.SQLException If an error occurs.

*/

List queryForList(String id) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects within a certain range.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @param skip The number of results to ignore.

* @param max The maximum number of results to return.

* @return A List of result objects.

* @throws java.sql.SQLException If an error occurs.

*/

List queryForList(String id, Object parameterObject, int skip, int max) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects within a certain range.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @param skip The number of results to ignore.

* @param max The maximum number of results to return.

* @return A List of result objects.

* @throws java.sql.SQLException If an error occurs.

*/

List queryForList(String id, int skip, int max) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns a number of

* result objects that will be handled one at a time by a

* RowHandler.

* <p/>

* This is generally a good approach to take when dealing with large sets

* of records (i.e. hundreds, thousands...) that need to be processed without

* eating up all of the system resources.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @param rowHandler A RowHandler instance

* @throws java.sql.SQLException If an error occurs.

*/

void queryWithRowHandler(String id, Object parameterObject, RowHandler rowHandler) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns a number of

* result objects that will be handled one at a time by a

* RowHandler.

* <p/>

* This is generally a good approach to take when dealing with large sets

* of records (i.e. hundreds, thousands...) that need to be processed without

* eating up all of the system resources.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @param rowHandler A RowHandler instance

* @throws java.sql.SQLException If an error occurs.

*/

void queryWithRowHandler(String id, RowHandler rowHandler) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects a page at a time.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @param pageSize The maximum number of result objects each page can hold.

* @return A PaginatedList of result objects.

* @throws java.sql.SQLException If an error occurs.

* @deprecated All paginated list features have been deprecated

*/

PaginatedList queryForPaginatedList(String id, Object parameterObject, int pageSize) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects a page at a time.

* <p/>

* This overload assumes no parameter is needed.

*

* @param id The name of the statement to execute.

* @param pageSize The maximum number of result objects each page can hold.

* @return A PaginatedList of result objects.

* @throws java.sql.SQLException If an error occurs.

* @deprecated All paginated list features have been deprecated

*/

PaginatedList queryForPaginatedList(String id, int pageSize) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects that will be keyed into a Map.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @param keyProp The property to be used as the key in the Map.

* @return A Map keyed by keyProp with values being the result object instance.

* @throws java.sql.SQLException If an error occurs.

*/

Map queryForMap(String id, Object parameterObject, String keyProp) throws SQLException;

/**

* Executes a mapped SQL SELECT statement that returns data to populate

* a number of result objects from which one property will be keyed into a Map.

* <p/>

* The parameter object is generally used to supply the input

* data for the WHERE clause parameter(s) of the SELECT statement.

*

* @param id The name of the statement to execute.

* @param parameterObject The parameter object (e.g. JavaBean, Map, XML etc.).

* @param keyProp The property to be used as the key in the Map.

* @param valueProp The property to be used as the value in the Map.

* @return A Map keyed by keyProp with values of valueProp.

* @throws java.sql.SQLException If an error occurs.

*/

Map queryForMap(String id, Object parameterObject, String keyProp, String valueProp) throws SQLException;

/**

* Starts a batch in which update statements will be cached before being sent to

* the database all at once. This can improve overall performance of updates update

* when dealing with numerous updates (e.g. inserting 1:M related data).

*

* @throws java.sql.SQLException If the batch could not be started.

*/

void startBatch() throws SQLException;

/**

* Executes (flushes) all statements currently batched.

*

* @return the number of rows updated in the batch

* @throws java.sql.SQLException If the batch could not be executed or if any of the statements

* fails.

*/

int executeBatch() throws SQLException;

/**

* Executes (flushes) all statements currently batched.

*

* @return a List of BatchResult objects. There will be one element in the

* list for each sub-batch executed. A sub-batch is created by adding a statement

* to the batch that does not equal the prior statement.

* @throws SQLException if a database access error occurs, or the drive

* does not support batch statements

* @throws BatchException if the driver throws BatchUpdateException

* @see com.ibatis.sqlmap.engine.execution.BatchException

*/

List executeBatchDetailed() throws SQLException, BatchException;

}