很久没细看过MyBatis了，时间一长就容易忘记。
下面是一个接口式编程的例子。
这里的例子一共分为4步：
1 首先要有一个namespace为接口的全类名的映射文件，该例中是 IMyUser.xml
2 然后在mybatis的容器(就是总的配置文件)里的mappers标签内
引入第1步中的映射文件，这里是 IMyUser.xml
3 通过SqlSession对象的getMapper(IMyUserDao.class)
获取一个接口的代理对象
4 调用代理对象的具体方法，也就是对应着 IMyUser.xml中的各个select,insert
等标签，这些标签的id属性同时必须与接口中的方法名一一对应
所需要的数据库表：
1 -- Create table 2 create table MYUSER 3 ( 4 id NUMBER not null, 5 username VARCHAR2(32) not null, 6 password VARCHAR2(128) not null, 7 administrator VARCHAR2(5) not null 8 ); 9 10 11 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 12 values ('1', 'weiyongle01', 'hr', 'hr'); 13 14 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 15 values ('352', 'weiyongle352', 'hr', 'hr'); 16 17 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 18 values ('353', 'weiyongle353', 'hr', 'hr'); 19 20 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 21 values ('354', '1', 'hr', 'hr'); 22 23 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 24 values ('355', 'weiyongle355', 'hr', 'hr'); 25 26 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 27 values ('359', 'weiyongle359', 'hr', 'hr'); 28 29 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 30 values ('360', 'weiyongle360', 'hr', 'wyl'); 31 32 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 33 values ('361', 'weiyongle361', 'hr', 'hr'); 34 35 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 36 values ('362', 'weiyongle362', 'hr', 'hr'); 37 38 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 39 values ('363', 'weiyongle363', 'hr', 'hr'); 40 41 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 42 values ('364', 'weiyongle364', 'hr', 'hr'); 43 44 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 45 values ('365', 'weiyongle365', 'hr', 'hr'); 46 47 insert into myuser (ID, USERNAME, PASSWORD, ADMINISTRATOR) 48 values ('390', 'weiyongle359', 'hr', 'hr');
1 MyBatis配置文件，Configuration.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!-- Copyright 2009-2016 the original author or authors. Licensed under the 3 Apache License, Version 2.0 (the "License"); you may not use this file except 4 in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 5 Unless required by applicable law or agreed to in writing, software distributed 6 under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES 7 OR CONDITIONS OF ANY KIND, either express or implied. See the License for 8 the specific language governing permissions and limitations under the License. --> 9 <!DOCTYPE configuration 10 PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 11 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 12 13 <configuration> 14 <settings> 15 <setting name="useGeneratedKeys" value="false" /> 16 <setting name="useColumnLabel" value="true" /> 17 </settings> 18 19 <!-- <typeAliases> <typeAlias alias="UserAlias" type="org.apache.ibatis.submitted.complex_property.User"/> 20 </typeAliases> --> 21 22 <environments default="development"> 23 <environment id="development"> 24 <transactionManager type="JDBC"> 25 <property name="" value="" /> 26 </transactionManager> 27 <dataSource type="UNPOOLED"> 28 <!-- Oracle数据库配置 --> 29 <property name="driver" value="oracle.jdbc.driver.OracleDriver" /> 30 <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl2" /> 31 <property name="username" value="hr" /> 32 <property name="password" value="hr" /> 33 </dataSource> 34 </environment> 35 </environments> 36 37 <!-- 配置的实体类 20161106添加 --> 38 <mappers> 39 <!-- <mapper resource="org/apache/ibatis/submitted/complex_property/User.xml" /> --> 40 <!-- 这个路径是从src下开始的，即以src作为根目录的， 41 这点和Resources.getResourcesAsStream("xx")里的xx一样，都是指向的具体文件的路径 42 ，都是以src为根目录 --> 43 <mapper resource="com/test/mybatis/config/MyUser.xml" /> 44 <!-- 接口式编程 --> 45 <!-- <mapper class="com.test.mybatis.dao.interf.IMyUserDao"/> --> 46 <mapper resource="com/test/mybatis/config/IMyUser.xml" /> 47 </mappers> 48 49 </configuration>
2 IMyUser.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!-- Copyright 2009-2016 the original author or authors. Licensed under the 3 Apache License, Version 2.0 (the "License"); you may not use this file except 4 in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 5 Unless required by applicable law or agreed to in writing, software distributed 6 under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES 7 OR CONDITIONS OF ANY KIND, either express or implied. See the License for 8 the specific language governing permissions and limitations under the License. --> 9 <!DOCTYPE mapper 10 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 11 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 12 <!-- MyBatis接口式编程 --> 13 <!-- 这里的namespace一定要是接口的全类名，这样就能够保证该mapper的唯一性 --> 14 <mapper namespace="com.test.mybatis.dao.interf.IMyUserDao"> 15 <!-- select标签里的id属性值 getUser 对应着 上面namespace里的方法， 16 实际上就是接口里定义的方法 --> 17 <select id="getUser" resultType="com.test.mybatis.entity.MyUser" parameterType="int"> 18 select * from MyUser where id = #{id} 19 </select> 20 <!-- select标签里的id属性值 getUserbyUser 对应着 上面namespace里的方法， 21 实际上就是接口里定义的方法 --> 22 <select id="getUserbyUser" parameterType="com.test.mybatis.entity.MyUser" resultType="com.test.mybatis.entity.MyUser" > 23 select * from MyUser 24 where 1=1 25 <!-- if 标签里的 test的属性值 username实际上是指的是 26 parameterType的属性值 com.test.mybatis.entity.MyUser 27 这个类里的一个成员属性，用于getter和setter方法， 28 不是之前理解的对应于数据库里的字段，还有username !='' 29 一定要写上，如果不写的话那么这个String类型的username成员变量 30 就会被MyBatis框架默认为"",从而可能会影响这里配置的slq的逻辑， 31 从而查询出来的结果可能会与我们自己设想中的不一样 --> 32 <if test="username != null and username !='' "> 33 AND username = #{username} 34 </if> 35 <if test="administrator != null and username !='' "> 36 AND administrator = #{administrator} 37 </if> 38 </select> 39 40 <delete id="deleteUser" parameterType="String"> 41 delete from MyUser where id = #{id} 42 </delete> 43 </mapper>
3.IMyUserDao.java
1 package com.test.mybatis.dao.interf; 2 3 import com.test.mybatis.entity.MyUser; 4 5 /** 6 * MyBatis接口式编程Demo 7 * @author Wei 8 * @time 2017年3月23日 下午1:26:21 9 */ 10 public interface IMyUserDao { 11 public MyUser getUser(int id); 12 public MyUser getUserbyUser(MyUser user); 13 public void deleteUser(String username); 14 }
4. IMyUserTest.java
1 package com.test.mybatis.dao.interf; 2 3 import java.io.IOException; 4 import java.io.InputStream; 5 6 import org.apache.ibatis.io.Resources; 7 import org.apache.ibatis.session.SqlSession; 8 import org.apache.ibatis.session.SqlSessionFactory; 9 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 10 import com.test.mybatis.entity.MyUser; 11 12 /** 13 * 接口式编程的测试类 14 * @author Wei 15 * @time 2017年3月23日 下午2:26:22 16 */ 17 public class IMyUserTest { 18 19 public IMyUserTest() { 20 // TODO Auto-generated constructor stub 21 } 22 23 public static void main(String[] args) { 24 InputStream is = null; 25 SqlSessionFactory factory = null; 26 SqlSession sqlsession = null; 27 try { 28 is = Resources.getResourceAsStream("com/test/mybatis/config/Configuration.xml"); 29 factory = new SqlSessionFactoryBuilder().build(is); 30 sqlsession = factory.openSession(); 31 /** 32 * 获取接口，实际上是通过代理模式来获取的代理对象 33 * 1 首先要有一个namespace为接口的全类名的映射文件，该例中是 IMyUser.xml 34 * 2 然后在mybatis的容器(就是总的配置文件)里的mappers标签内 35 * 引入第1步中的映射文件，这里是 IMyUser.xml 36 * 3 通过SqlSession对象的getMapper(IMyUserDao.class) 37 * 获取一个接口的代理对象 38 * 4 调用代理对象的具体方法，也就是对应着 IMyUser.xml中的各个select,insert 39 * 等标签，这些标签的id属性同时必须与接口中的方法名一一对应 40 */ 41 IMyUserDao dao = sqlsession.getMapper(IMyUserDao.class); 42 MyUser user = new MyUser(); 43 user.setUsername("weiyongle363"); 44 // user.setAdministrator("wyl"); 45 //调用接口的方法 46 user = dao.getUserbyUser(user);//正常 47 // user = dao.getUser(361);//正常运行 48 // user = dao.getUser(355); 49 // MyUser user = sqlsession.selectOne("com.test.mybatis.dao.interf.IMyUserDao.getUser",1); 50 if(user!=null){ 51 System.out.println(user.toString()); 52 }else{ 53 System.out.println("没有查询到结果"); 54 } 55 56 } catch (IOException e) { 57 // TODO Auto-generated catch block 58 e.printStackTrace(); 59 } 60 } 61 }
执行结果：
