本章概要
- MyBatis 多数据源
5.4.2 MyBatis 多数据源
项目目录结构
1. 准备工作
数据库
create database `chapter05-1` default character set utf8;
CREATE TABLE `chapter05-1`.`book` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`author` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `chapter05-1`.`book`(`id`, `name`, `author`) VALUES (1, '水浒传', '施耐庵');
create database `chapter05-2` default character set utf8;
CREATE TABLE `chapter05-2`.`book` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`author` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `chapter05-2`.`book`(`id`, `name`, `author`) VALUES (1, '三国演义', '罗贯中');
创建 Spring Boot Web 项目，添加如下依赖：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
application.properties 配置
# 数据源1
spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.one.url=jdbc:mysql://localhost:3306/chapter05-1?useUnicode=true&characterEncoding=utf8&useSSL=true
spring.datasource.one.username=root
spring.datasource.one.password=root
# 数据源2
spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.two.url=jdbc:mysql://localhost:3306/chapter05-2?useUnicode=true&characterEncoding=utf8&useSSL=true
spring.datasource.two.username=root
spring.datasource.two.password=root
数据源配置 DataSourceConfig
@Configuration
public class DataSourceConfig {
@Bean
@ConfigurationProperties("spring.datasource.one")
DataSource dsOne() {
return DruidDataSourceBuilder.create().build();
}
@Bean
@ConfigurationProperties("spring.datasource.two")
DataSource dsTwo() {
return DruidDataSourceBuilder.create().build();
}
}
实体类 Book
public class Book {
private Integer id;
private String name;
private String author;
@Override
public String toString() {
return "Book{" +
"id=" + id +
", name='" + name + '\'' +
", author='" + author + '\'' +
'}';
}
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;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}
静态资源配置 pom.xml
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
</build>
2. 创建 MyBatis 配置
配置 MyBatis ，主要提供 SqlSessionFactory 实例和 SqlSessionTemplate 实例
@Configuration
@MapperScan(value = "com.sang.mapper1", sqlSessionFactoryRef = "sqlSessionFactoryBean1")
public class MyBatisConfigOne {
@Autowired
@Qualifier("dsOne")
DataSource dsOne;
@Bean
SqlSessionFactory sqlSessionFactoryBean1() throws Exception {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dsOne);
return factoryBean.getObject();
}
@Bean
SqlSessionTemplate sqlSessionTemplate1() throws Exception {
return new SqlSessionTemplate(sqlSessionFactoryBean1());
}
}
代码解释：
- 在 @MapperScan 注解中指定 Mapper 接口所在的位置，同时指定 SqlSessionFactory 的实例名，则该位置下的 Mapper 将使用 SqlSessionFactory 实例
- 提供 SqlSessionFactory 的实例，直接创建出来，同时将 DataSource 的实例设置给 SqlSessionFactory ，这里创建的 SqlSessionFactory 实例也就是 @MapperScan 注解中的 sqlSessionFactoryRef 参数指定的实例
- 提供一个 SqlSessionTemplate 实例。这是一个线程安全类，主要用来管理 MyBatis 中的 SqlSession 操作
参考 MyBatisConfigOne 创建 MyBatisConfigTwo
@Configuration
@MapperScan(value = "com.sang.mapper2", sqlSessionFactoryRef = "sqlSessionFactoryBean2")
public class MyBatisConfigTwo {
@Autowired
@Qualifier("dsTwo")
DataSource dsTwo;
@Bean
SqlSessionFactory sqlSessionFactoryBean2() throws Exception {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dsTwo);
return factoryBean.getObject();
}
@Bean
SqlSessionTemplate sqlSessionTemplate2() throws Exception {
return new SqlSessionTemplate(sqlSessionFactoryBean2());
}
}
3. 创建 Mapper
分别在 com.sang.mapper1 和 com.sang.mapper2 包下创建两个不同的 Mapper 以及相应的 Mapper 映射文件
mapper1 下
public interface BookMapper {
List<Book> getAllBooks();
}
<?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.sang.mapper1.BookMapper">
<select id="getAllBooks" resultType="com.sang.model.Book">
select * from book;
</select>
</mapper>
mapper2 下
public interface BookMapper2 {
List<Book> getAllBooks();
}
<?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.sang.mapper2.BookMapper2">
<select id="getAllBooks" resultType="com.sang.model.Book">
select * from book;
</select>
</mapper>
这两个不同的 Mapper 将操作不同的数据源
4. 创建 Controller
简便起见，这里直接将 Mapper 注入 Controller 中
@RestController
public class BookController {
@Autowired
BookMapper bookMapper;
@Autowired
BookMapper2 bookMapper2;
@GetMapping("/test1")
public void test1() {
List<Book> books1 = bookMapper.getAllBooks();
List<Book> books2 = bookMapper2.getAllBooks();
System.out.println("books1:"+books1);
System.out.println("books2:"+books2);
}
}
5. 测试
http://localhost:8081/test1，日志如下：
books1:[Book{id=1, name='水浒传', author='施耐庵'}]
books2:[Book{id=1, name='三国演义', author='罗贯中'}]