关于springboot:Spring-Boot-搭配MyBatis及Druid实现多数据源可自动切换

原文地址：https://blog.lanweihong.com/p...

Github： spring-boot-mybatis-multiple-data-source

增加相干依赖包

编辑 pom.xml 文件，增加相干依赖：

<parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>2.4.8</version>        <relativePath/>    </parent>    <properties>        <mysql.driver.version>8.0.16</mysql.driver.version>        <mybatis.spring.boot.version>1.3.2</mybatis.spring.boot.version>        <druid.version>1.1.10</druid.version>        <tk.mybatis.version>2.1.5</tk.mybatis.version>        <lombok.version>1.16.18</lombok.version>    </properties>    <dependencies>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <version>${lombok.version}</version>        </dependency>        <dependency>            <groupId>org.mybatis.spring.boot</groupId>            <artifactId>mybatis-spring-boot-starter</artifactId>            <version>${mybatis.spring.boot.version}</version>        </dependency>        <!-- mysql driver -->        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>${mysql.driver.version}</version>        </dependency>        <dependency>            <groupId>com.alibaba</groupId>            <artifactId>druid-spring-boot-starter</artifactId>            <version>${druid.version}</version>            <exclusions>                <exclusion>                    <groupId>org.springframework.boot</groupId>                    <artifactId>spring-boot-autoconfigure</artifactId>                </exclusion>            </exclusions>        </dependency>        <dependency>            <groupId>tk.mybatis</groupId>            <artifactId>mapper-spring-boot-starter</artifactId>            <version>${tk.mybatis.version}</version>        </dependency>    </dependencies>

配置 `application.yml` 文件

在配置文件 application.yml 中配置数据源：

spring:  datasource:    type: com.alibaba.druid.pool.DruidDataSource    username: root    password: Aa123456.    druid:      driver-class-name: com.mysql.cj.jdbc.Driver      initial-size: 5      max-active: 50      max-wait: 60000      min-idle: 5      # 配置 book 数据源，可自定义      book:        # type: com.alibaba.druid.pool.DruidDataSource        # driver-class-name: com.mysql.cj.jdbc.Driver        url: jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=Asia/Shanghai        # username: root        # password: 1      # 配置 user 数据源      user:        url: jdbc:mysql://localhost:3306/db02?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=Asia/Shanghai        # 重新配置明码，未配置则默认应用以上配置的        username: root        password: 1

手动配置数据源

主数据源配置

创立配置类 BookDataSourceConfig ，配置类须要对 DataSource、DataSourceTransactionManager、SqlSessionFactory 、SqlSessionTemplate 四个数据项进行配置。当零碎中存在多个数据源时，必须有一个数据源为主数据源，应用 @Primary 注解润饰。

BookDataSourceConfig 配置类：

@Configuration// 通过在 `@MapperScan` 注解中配置 `basePackages` 和 `sqlSessionTemplateRef` 来实现主动切换数据源@MapperScan(basePackages = "com.lanweihong.dao.book",        sqlSessionFactoryRef = "bookSqlSessionFactory", sqlSessionTemplateRef = "bookSqlSessionTemplate")public class BookDataSourceConfig {    public static final String MAPPER_LOCATION = "classpath:mapper/book/*.xml";    /**     * 主数据源     * 阐明：@Primary 如果有多个同类的Bean，该Bean优先思考，多数据源时必须配置一个主数据源，用该注解标记     * @return     */    @Primary    @Bean("bookDataSource")    @ConfigurationProperties("spring.datasource.druid.book")    public DataSource bookDataSource(){        return DruidDataSourceBuilder.create().build();    }    @Primary    @Bean("bookTransactionManager")    public DataSourceTransactionManager bookTransactionManager() {        return new DataSourceTransactionManager(bookDataSource());    }    @Primary    @Bean("bookSqlSessionFactory")    public SqlSessionFactory sqlSessionFactory(@Qualifier("bookDataSource") DataSource dataSource) throws Exception {        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();        sqlSessionFactoryBean.setDataSource(dataSource);        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(MAPPER_LOCATION));        return sqlSessionFactoryBean.getObject();    }    @Primary    @Bean("bookSqlSessionTemplate")    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("bookDataSource") DataSource dataSource) throws Exception {        return new SqlSessionTemplate(sqlSessionFactory(dataSource));    }}

Mybatis 是通过配置的扫描包和对应的 sqlSessionTemplate 来主动切换数据源，即通过在 @MapperScan 注解中配置 basePackages 和 sqlSessionTemplateRef：

@MapperScan(basePackages = "com.lanweihong.dao.book",        sqlSessionFactoryRef = "bookSqlSessionFactory", sqlSessionTemplateRef = "bookSqlSessionTemplate")

配置第二个数据源

编写配置类 UserDataSourceConfig：

@Configuration@MapperScan(basePackages = "com.lanweihong.dao.user", sqlSessionTemplateRef = "userSqlSessionTemplate")public class UserDataSourceConfig {    public static final String MAPPER_LOCATION = "classpath:mapper/user/*.xml";    /**     * user 数据源     * @return     */    @Bean("userDataSource")    @ConfigurationProperties("spring.datasource.druid.user")    public DataSource userDataSource(){        return DruidDataSourceBuilder.create().build();    }    @Bean("userTransactionManager")    public DataSourceTransactionManager userTransactionManager() {        return new DataSourceTransactionManager(userDataSource());    }    @Bean("userSqlSessionFactory")    public SqlSessionFactory userSqlSessionFactory(@Qualifier("userDataSource") DataSource dataSource) throws Exception {        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();        sqlSessionFactoryBean.setDataSource(dataSource);        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(MAPPER_LOCATION));        return sqlSessionFactoryBean.getObject();    }    @Bean("userSqlSessionTemplate")    public SqlSessionTemplate userSqlSessionTemplate(@Qualifier("userDataSource") DataSource dataSource) throws Exception {        return new SqlSessionTemplate(userSqlSessionFactory(dataSource));    }}

至此，不同数据源的配置已实现，接下来应用了。

应用

按平时失常写和应用 DAO 和 Service，Spring 会依据数据源配置的映射主动切换相应的数据源，不须要在 Service 中指定，间接应用即可。

以下 DAO/Mapper/Service/Controller 代码为示例代码，仅列出局部代码，残缺代码请看： https://github.com/lanweihong...

IBookDao：

public interface IBookDao extends BaseMapper<BookDO> {    BookDO getByBookName(@Param("bookName") String bookName);}

BookMapper.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.lanweihong.dao.book.IBookDao">    <resultMap id="BaseResultMap" type="com.lanweihong.entity.BookDO">        <id column="id" jdbcType="BIGINT" property="id" />        <result column="version" jdbcType="INTEGER" property="version" />        <result column="book_name" jdbcType="VARCHAR" property="bookName" />        <result column="status" jdbcType="TINYINT" property="status" />        <result column="add_time" jdbcType="TIMESTAMP" property="addTime" />    </resultMap>    <sql id="BaseColumnList">        id, version, book_name, status, add_time    </sql>    <select id="getByBookName" resultMap="BaseResultMap">        SELECT <include refid="BaseColumnList" /> FROM book WHERE book_name = #{bookName}    </select>    </mapper>

Service：

@Service("bookService")public class BookServiceImpl implements IBookService {    private final IBookDao bookDao;    @Autowired    public BookServiceImpl(IBookDao bookDao) {        this.bookDao = bookDao;    }    @Override    public List<BookDO> listAll() {        return bookDao.selectAll();    }    @Override    public BookDO getByBookName(String bookName) {        return bookDao.getByBookName(bookName);    }}

Controller：

@RestController@RequestMapping("/api/v1/")public class MainController {    private final IUserService userService;    private final IBookService bookService;    @Autowired    public MainController(IUserService userService, IBookService bookService) {        this.userService = userService;        this.bookService = bookService;    }    @GetMapping("/books")    public Map<String, Object> queryBooks(@RequestParam(value = "name", required = false) String bookName) {        List<BookDO> books = new ArrayList<>();        if (StringUtil.isEmpty(bookName)) {            books = this.bookService.listAll();        } else {            BookDO book = bookService.getByBookName(bookName);            books.add(book);        }        Map<String, Object> result = new HashMap<>(1);        result.put("data", books);        return result;    }    @GetMapping("/users")    public Map<String, Object> queryUsers(@RequestParam(value = "name", required = false) String userName) {        List<UserDO> users = new ArrayList<>();        if (StringUtil.isEmpty(userName)) {            users = this.userService.listAll();        } else {            UserDO user = userService.getByUserName(userName);            users.add(user);        }        Map<String, Object> result = new HashMap<>(1);        result.put("data", users);        return result;    }}

测试

启动利用，在浏览器中拜访 http://127.0.0.1:8015/api/v1/users 及 http://127.0.0.1:8015/api/v1/books 测试；

我的项目构造

我的项目构造如下图：

代码已上传至 Github：spring-boot-mybatis-multiple-data-source

参考文档

https://blog.csdn.net/acquain...