MyBatis(iBatis 3)入门示例 及 整合Mybatis与Spring3

 

以前的iBatis 项目在2010 年5 月，将代码库迁致Google Code，并更名为MyBatis。

本示例用的是ibatis-3-core-3.0.0.208.zip，首先加如mybatis和mysql数据库的jar包。

 

table.sql

 

create database mybatis;  
use mybatis;  
create table user(  
    id int primary key auto_increment,  
    name varchar(50)  
);  
insert into user values(null,'张三'); 

 

 

configuration.xml

 

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">  
<configuration>     
    <typeAliases>  
        <typeAlias alias="User" type="com.nantian.mybatis.model.User"/>  
    </typeAliases>  
      
    <environments default="development">  
        <environment id="development">  
            <transactionManager type="JDBC"/>  
            <dataSource type="POOLED">  
                <property name="driver" value="com.mysql.jdbc.Driver"/>  
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis"/>  
                <property name="username" value="root"/>  
                <property name="password" value="root"/>  
            </dataSource>  
        </environment>  
    </environments>  
      
    <mappers>  
        <mapper resource="com/nantian/mybatis/model/UserMapper.xml"/>  
    </mappers>  
</configuration>  

 

 

DBUtil

 

package com.nantian.mybatis.data;  
  
import java.io.IOException;  
import java.io.Reader;  
  
import org.apache.ibatis.io.Resources;  
import org.apache.ibatis.session.SqlSessionFactory;  
import org.apache.ibatis.session.SqlSessionFactoryBuilder;  
  
public class DBUtil {  
    private static final DBUtil dbUtil = new DBUtil();  
    private SqlSessionFactory sqlSessionFactory = null;  
  
    private DBUtil() {  
        try {  
            String resource = "com/nantian/mybatis/data/configuration.xml";  
            Reader reader = Resources.getResourceAsReader(resource);  
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);  
            reader.close();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
    }  
  
    public static DBUtil getInstance() {  
        return dbUtil;  
    }  
  
    public SqlSessionFactory getSqlSessionFactory() {  
        return sqlSessionFactory;  
    }  
}  

 

 

User

 

package com.nantian.mybatis.model;  
  
public class User {  
    private int id;  
    private String name;  
  
    public int getId() {  
        return id;  
    }  
  
    public void setId(int id) {  
        this.id = id;  
    }  
  
    public String getName() {  
        return name;  
    }  
  
    public void setName(String name) {  
        this.name = name;  
    }  
}  

 

 

UserMapper

 

package com.nantian.mybatis.model;  
  
public interface UserMapper {  
    public User selectUser(int id);  
}  

 

 

 

UserMapper.xml

 

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">  
<mapper namespace="com.nantian.mybatis.model.UserMapper">  
    <select id="selectUser" parameterType="int" resultType="User">  
        select id,name from user where id = #{id}  
    </select>  
</mapper>  

 

 

Test

 

package com.nantian.mybatis.test;  
  
import junit.framework.TestCase;  
  
import org.apache.ibatis.session.SqlSession;  
  
import com.nantian.mybatis.data.DBUtil;  
import com.nantian.mybatis.model.User;  
import com.nantian.mybatis.model.UserMapper;  
  
public class Test extends TestCase {  
    public void selectUser() {  
        SqlSession sqlSession = DBUtil.getInstance().getSqlSessionFactory()  
                .openSession();  
        try {  
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);  
            User user = userMapper.selectUser(1);  
            System.out.println(user.getName());  
        } finally {  
            sqlSession.close();  
        }  
    }  
}  

 

 

Mybatis3可以使用注解了。注解是非常简单明了的，但是JAVA 注解既有局限性，在语句比较复杂的情况下又比较容易混乱。所以，如果你的语句比较复杂，最好还是使用XML 来映射语句。这主要取决于你和你的项目团队，决定哪个更适合于你，主要还是以稳健为主。也就是说，你不需要制约于哪一种方式，你可以很容易的把注解转为XML，也可以把XML 转化为注解。

 

 

 

 

整合Mybatis与Spring3

http://www.iteye.com/topic/1018134

 

1.实体bean 

package org.hyn.bean;

public class User {
    private int id;
    private String name;
    private int age;
...//长长的set get 方法

2.Mapper及配置文件

package org.hyn.maper;

import org.hyn.bean.User;

public interface UserMapper {
    public void insertUser(User user);

    public User getUser(String name);
}

 

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="org.hyn.maper.UserMapper">
    <insert id="insertUser" parameterType="org.hyn.bean.User">
        insert into user(name,age) values(#{name},#{age})
        </insert>
    <select id="getUser" resultType="org.hyn.bean.User"
        parameterType="java.lang.String">
        select * from user where name=#{name}
       </select>

    <!-- 当使用该Mybatis与Spring整合的时候，该文件必须和相应的Mapper接口文件同名，并在同一路径下 -->
</mapper>

3.spring配置文件

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="myDataSource" />

    <!-- <property name="configLocation" value=""/> -->
    <!--
        该属性用来指定MyBatis的XML配置文件路径,跟Spring整合时，编写MyBatis映射文件的目的无非是配置一下typeAlias、setting之类的元素。不用在其中指定数据源，或者事务处理方式。就算配置了也会被忽略。因为这些都是使用Spring中的配置
        。当然如果你不打算添加typeAlias 之类的设置的话，你连MyBatis的配置文件都不用写，更不用配置这个属性了
    -->

    <!--<property name="mapperLocations" value="src/UserMapper.xml"/>-->
    <!-- 该配置文件用来指定Mapper映射文件的位置 ，如果映射文件与相应的接口同名，且在同一路径下，那么可以不配置该选项-->
</bean>

<!--  注册Mapper方式一
<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
    <property name="mapperInterface" value="org.hyn.maper.UserMapper"/>
    <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>
-->

<!-- 注册Mapper方式二：也可不指定特定mapper，而使用自动扫描包的方式来注册各种Mapper ，配置如下：-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="org.hyn.maper" />
</bean>

4.测试类

@Test
public void testGetUser() {
    ApplicationContext aContext = new FileSystemXmlApplicationContext("WebRoot/WEB-INF/applicationContext.xml");
    UserMapper userMapper = aContext.getBean(UserMapper.class);
    User user = userMapper.getUser("张三");
    System.out.println(user.toString());
}

@Test
public void testAddUser(){
    ApplicationContext aContext = new FileSystemXmlApplicationContext("WebRoot/WEB-INF/applicationContext.xml");
    UserMapper userMapper = aContext.getBean(UserMapper.class);
    User user = new User();
    user.setName("张三");
    user.setAge(18);
    userMapper.insertUser(user);
    System.out.println("添加成功");
}

 

 

 

 

下面付上源代码

 

 

 

mybatis mapper pojo的两种方式

 

1.如果数据库和pojo的属性名都一样的话可以用如下方式：

<select id="getUser" resultType="org.guarx.domain.User" parameterType="java.lang.String">
      <![CDATA[select * from users where id=#{value}]]>
</select>
<select id="getUsers" resultType="org.guarx.domain.User">
      <![CDATA[select * from users]]>
</select>

 

 

2.如果数据库columns name和pojo的属性名称不一样（大多数情况下）

（1）第一种方式：

 

<select id="getUsers" resultType="org.guarx.domain.User">
        <![CDATA[select t_id as id,t_username as name,t_desc as description from users]]>
</select>

 

 

（2）第二种方式：

 

<resultMap type="org.guarx.domain.User" id="userMapper">
        <result column="t_id" property="id"/>
        <result column="t_username" property="username"/>
        <result column="t_desc" property="description"/>
</resultMap>

<select id="getAll" resultMap="userMapper">
        <![CDATA[select id,username,description from users ]]>
</select>