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【转】Mybatis/Ibatis,数据库操作的返回值
阅读量:7247 次
发布时间:2019-06-29

本文共 18536 字,大约阅读时间需要 61 分钟。

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):

select nextval('desktop_unlock_tag_id_seq') as id
insert into desktop_unlock_tag(id,name,description,priority) values(#id:INTEGER#,#name:VARCHAR#,#description:VARCHAR#,#priority:INTEGER#)
update desktop_unlock_tag set modify_time=now(),priority=#priority:INTEGER#, name=#name:VARCHAR#,description=#description:VARCHAR# where id=#id:INTEGER#
delete from desktop_unlock_tag where id=#value:INTEGER#
select id,name,description,priority from desktop_unlock_tag

我的DAO源码如下:

public class UnlockTagDaoImpl extends SqlMapClientDaoSupport implements        UnlockTagDao {    @Override    public Integer addItem(String name, String desc, Integer priority) {        SqlMapClientTemplate template = this.getSqlMapClientTemplate();        Map
args = new HashMap
(); 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
args = new HashMap
(); 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
listAll(Integer nStart, Integer nSize, boolean bCountTotal) { SqlMapClientTemplate template = this.getSqlMapClientTemplate(); PagedList
result = new PagedList
(); if (bCountTotal) { int total = (Integer) template .queryForObject("DesktopCommon.countUnlockTagInfo"); result.setTotal(total); } Map
args = new HashMap
(); args.put("start", nStart); args.put("size", nSize); @SuppressWarnings("unchecked") List
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):

/* *  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.   * 

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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. *

* 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;}

 

 

转载自:http://blog.csdn.net/gaojinshan/article/details/24308313

 

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