Spring整合mybatis

思路分析

Mybatis程序核心对象分析

上面图片是mybatis的代码，上述有三个对象，分别是sqlSessionFactory，sqlSession，accountDao这三个对象，那么哪个是核心对象，哪些类适合交给Spring来管理，因为spring默认是单例的，所有他管理的核心对象最好是无状态的，单例的，对于sqlSessionFactory来说它只创建一次，而sqlSession每次用的时候都要获取，用完还要关闭，而accountDao更不用说了，它本来就是由sqlSession创建的。(就像是在没学框架之前写那个mybatis工具类时只需在工具类中创建一次sqlSessionFactory对象，之后都是由工具类创建sqlSession对象)所以核心对象就是sqlSessionFactory对象

整合Mybatis

• 使用SqlSessionFactoryBean封装SqlSessionFactory需要的环境信息

• 使用MapperScannerConfigurer加载Dao接口，创建代理对象保存到IOC容器中

代码实现

前置工作
创建与数据库表对应的实体类，还有dao接口并写对应的方法以及对应的sql语句

public class Student {private Integer id;private String name;public Student() {}public Student(Integer id, String name) {this.id = id;this.name = name;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic String toString() {return "Student{" +"id=" + id +", name='" + name + '\'' +'}';}
}

public interface StudentDao {@Select("select * from student where id = #{id}")Student findById(Integer id);
}

1. 导入依赖

 <dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.11</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.0</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.16</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.46</version></dependency></dependencies>

2. 创建JdbcConfig配置DataSource数据源

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring_db?useSSL=false
jdbc.username=root
jdbc.password=root

JdbcConfig

public class JdbcConfig {@Value("${jdbc.driver}")private String driver;@Value("${jdbc.url}")private String url;@Value("${jdbc.username}")private String userName;@Value("${jdbc.password}")private String password;@Beanpublic DataSource dataSource(){DruidDataSource ds = new DruidDataSource();ds.setDriverClassName(driver);ds.setUrl(url);ds.setUsername(userName);ds.setPassword(password);return ds;}
}

3. 创建MybatisConfig整合Mybatis

public class MybatisConfig {//定义bean，SqlSessionFactoryBean，用于产生SqlSessionFactory对象@Beanpublic SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();ssfb.setTypeAliasesPackage("com.itheima.domain");ssfb.setDataSource(dataSource);return ssfb;}//定义bean，返回MapperScannerConfigurer对象@Beanpublic MapperScannerConfigurer mapperScannerConfigurer(){MapperScannerConfigurer msc = new MapperScannerConfigurer();msc.setBasePackage("com.itheima.dao");return msc;}
}

4. 创建SpringConfig主配置类进行包扫描和加载其他配置类

@Configuration
@ComponentScan("com.itheima")
//@PropertySource：加载类路径jdbc.properties文件
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
public class SpringConfig {
}

5. 定义测试类进行测试

public class App {public static void main( String[] args ) {AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);StudentDao studentDao = ctx.getBean(StudentDao.class);Student student = studentDao.findById(3);System.out.println(student);}
}

Spring整合Junit

1. 导入依赖坐标

   <dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>5.2.10.RELEASE</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13</version></dependency>

2. 测试哪个类在test包下创建相同包的类(规范)

3. 使用Spring整合junit专用的类加载器和加载配置类

//【第二步】使用Spring整合Junit专用的类加载器
@RunWith(SpringJUnit4ClassRunner.class)
//【第三步】加载配置文件或者配置类	
@ContextConfiguration(classes = {SpringConfiguration.class}) //加载配置类
//@ContextConfiguration(locations={"classpath:applicationContext.xml"})//加载配置文件
public class AccountServiceTest {//支持自动装配注入bean@Autowiredprivate StudentDao studentDao;@Testpublic void testFindById(){Student student = studentDao.findById(1);System.out.println(student);}
}

注意：junit的依赖至少要是4.12版本,可以是4.13等版本,否则出现如下异常

修改成警告

如何将上图中箭头处修改成警告，看下图
鼠标点击studentDao处，按alt+enter键