这篇文章主要是一个基本的例子,分为两个部分,mybatis独立的配置mybatis-spring配置
项目的最终地址在这里:https://github.com/shellj/mybatis-example

Mybatis单独的配置

根据官方的例子进行配置

http://www.mybatis.org/mybatis-3/zh/getting-started.html

新建maven项目

添加依赖,目前需要的依赖包如下:

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<dependencies>  
    <dependency>  
        <groupId>org.mybatis</groupId>  
        <artifactId>mybatis</artifactId>  
        <version>3.4.1</version>  
    </dependency>  
    <dependency>  
        <groupId>ch.qos.logback</groupId>  
        <artifactId>logback-classic</artifactId>  
        <version>1.1.7</version>  
    </dependency>  
    <dependency>  
        <groupId>mysql</groupId>  
        <artifactId>mysql-connector-java</artifactId>  
        <version>5.1.39</version>  
    </dependency>  
  
    <dependency>  
        <groupId>junit</groupId>  
        <artifactId>junit</artifactId>  
        <version>4.12</version>  
    </dependency>  
</dependencies>  

创建Blog表

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CREATE TABLE blog (  
    `id` bigint(19) NOT NULL AUTO_INCREMENT,  
    `author` varchar(64),  
    `title` varchar(128),  
    `content` varchar(512),  
    `create_date` datetime,  
    PRIMARY KEY (`id`)  
) ENGINE=`InnoDB` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci COMMENT='blog';  

创建实体类,mapper与mybatis config

其中mybatis config文件里需要的一些数据库配置信息通过引入properties配置文件获取,新建一个system.properties文件。

mybatis-config.xml
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<configuration>  
    <properties resource="system.properties"/>  
</configuration>  
system.properties
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jdbc.driver=com.mysql.jdbc.Driver  
jdbc.url=jdbc:mysql://10.211.55.6:3306/blog?useUnicode=true&characterEncoding=utf-8  
jdbc.username=root  
jdbc.password=******  

程序验证

上面执行完大概会有下面图片的结构,当然具体的一些结构根据实际情况会有所不同。

好了,基本的mybatis数据操作就可以了,现在可以写个测试程序来测试程序是否正常运行,

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public class BlogTest {  
    private static final Logger logger = LoggerFactory.getLogger(BlogTest.class);  
  
    SqlSessionFactory sqlSessionFactory;  
  
    @Before  
    public void init() throws IOException {  
        String resource = "mybatis/mybatis-config.xml";  
        InputStream inputStream = Resources.getResourceAsStream(resource);  
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);  
    }  
  
    @Test  
    public void insertTest() throws Exception {  
        Blog blog = new Blog("标题", "shellj", "很多内容");  
        try (SqlSession sqlSession = sqlSessionFactory.openSession(true)) {  
            int insert = sqlSession.insert("Blog.insert", blog);  
            logger.info("id:" + blog.getId());  
            assertEquals(1, insert);  
        }  
    }  
}  

更好的方式

使用上面那种sqlSession.insert()方式显然有些不方便,mybatis也提供了一种更直观的操作方式,Mapper方式。
添加BlogMapper interface:

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public interface BlogMapper {  
    int insert(Blog blog);  
  
    Blog selectById(Long id);  
}  

然后将BlogMapper.xml里的namespace改为me.shellj.example.mybatis.mapper.BlogMapper,至于为什么,官方有解释:

你可能注意到这和使用完全限定名调用 Java 对象的方法是相似的,之所以这样做是有原因的。这个命名可以直接映射到在命名空间中同名的 Mapper 类,并在已映射的 select 语句中的名字、参数和返回类型匹配成方法。这样你就可以向上面那样很容易地调用这个对应 Mapper 接口的方法。

接下来我们就可以通过更简单的方式查询数据了:

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@Test  
public void selectTest() throws Exception {  
    try (SqlSession sqlSession = sqlSessionFactory.openSession(true)) {  
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);  
        Blog blog = mapper.selectById(1L);  
        assertNotNull(blog);  
        logger.info(blog.toString());  
    }  
}  

当然有些简单的sql可以直接注解卸载BlogMapper.java里面,但推荐都写在xml映射文件里。

mybatis-spring

http://www.mybatis.org/spring/zh/getting-started.html

主要是设置SqlSessionFactoryBeanMapperScannerConfigurer就好了,xml,mapper和model不需要变,把下面的相应地址改掉就好了,配置如下:

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<?xml version="1.0" encoding="UTF-8"?>  
<beans xmlns="http://www.springframework.org/schema/beans"  
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
       xmlns:context="http://www.springframework.org/schema/context"  
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">  
  
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">  
        <property name="location" value="system.properties"/>  
        <property name="fileEncoding" value="utf-8"/>  
    </bean>  
  
    <bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close">  
        <property name="driverClassName" value="${jdbc.driver}"/>  
        <property name="url" value="${jdbc.url}"/>  
        <property name="username" value="${jdbc.username}"/>  
        <property name="password" value="${jdbc.password}"/>  
        <property name="minEvictableIdleTimeMillis" value="7200000"/>  
        <property name="testWhileIdle" value="true"/>  
        <property name="validationQuery" value="select 'x'"/>  
    </bean>  
  
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
        <property name="dataSource" ref="dataSource"/>  
        <property name="mapperLocations" value="spring/mapper/*.xml"/>  
    </bean>  
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">  
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>  
        <property name="basePackage" value="me.shellj.example.spring.mapper"/>  
    </bean>  
  
    <context:component-scan base-package="me.shellj.example.spring"></context:component-scan>  
</beans>  

然后spring就会自动注入mapper,跑一个测试:

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@RunWith(SpringRunner.class)  
@ContextConfiguration(locations = "classpath:spring/mybatis-spring.xml")  
public class SpringBlogTest {  
    private static final Logger logger = LoggerFactory.getLogger(SpringBlogTest.class);  
  
    @Autowired  
    private BlogMapper blogMapper;  
  
    @Test  
    public void insert() throws Exception {  
        Blog blog = new Blog();  
        blog.setAuthor("名字spring");  
        blog.setTitle("title");  
        blog.setContent("content");  
        int insert = blogMapper.insert(blog);  
        assertEquals(1, insert);  
        logger.info(blog.toString());  
    }  
  
    @Test  
    public void select() throws Exception {  
        BlogExample example = new BlogExample();  
        example.createCriteria().andAuthorEqualTo("名字spring");  
        List<Blog> blogs = blogMapper.selectByExample(example);  
        assertNotNull(blogs);  
        assertEquals(1, blogs.size());  
        logger.info(blogs.get(0).toString());  
    }  
}