对于Mybatis的多数据源动态切换，你有多少了解呢？让大佬告诉你

今天跟大家分享Mybatis多数据源动态切换的知识。

1 Mybatis多数据源动态切换

首先需要建立两个库进行测试，我这里使用的是master_test和slave_test两个库，两张库都有一张同样的表（偷懒），表名 t_user

字段名类型备注idint主键自增IDnamevarchar名称

表中分别添加两条不同数据，方便测试 主数据库记录name为xiaobin，从库为xiaoliu。

目录结构

开始使用Springboot 整合mybatis，首先引入pom文件。

   <?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0"        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">   <modelVersion>4.0.0</modelVersion>   <parent>       <groupId>org.springframework.boot</groupId>       <artifactId>spring-boot-starter-parent</artifactId>       <version>2.1.4.RELEASE</version>   </parent>   <groupId>com.xiaobin</groupId>   <artifactId>mysql_master_slave</artifactId>   <version>1.0-SNAPSHOT</version>   <properties>       <java.version>1.8</java.version>       <lombok.version>1.18.6</lombok.version>       <mybatis.version>1.3.2</mybatis.version>       <lombox.version>1.18.6</lombox.version>   </properties>   <dependencies>       <!-- 添加web启动坐标 -->       <dependency>           <groupId>org.springframework.boot</groupId>           <artifactId>spring-boot-starter-web</artifactId>       </dependency>       <!-- 添加lombok工具坐标 -->       <dependency>           <groupId>org.projectlombok</groupId>           <artifactId>lombok</artifactId>           <version>${lombok.version}</version>       </dependency>       <!-- 添加springboot 测试坐标 -->       <dependency>           <groupId>org.springframework.boot</groupId>           <artifactId>spring-boot-starter-test</artifactId>       </dependency>       <!-- 添加lombox 测试坐标 -->       <dependency>           <groupId>org.projectlombok</groupId>           <artifactId>lombok</artifactId>           <version>${lombox.version}</version>       </dependency>       <!-- 添加mybatis依赖坐标 -->       <dependency>           <groupId>org.mybatis.spring.boot</groupId>           <artifactId>mybatis-spring-boot-starter</artifactId>           <version>${mybatis.version}</version>       </dependency>       <!-- 添加mysql驱动器坐标 -->       <dependency>           <groupId>mysql</groupId>           <artifactId>mysql-connector-java</artifactId>       </dependency>       <dependency>           <groupId>org.springframework.boot</groupId>           <artifactId>spring-boot-starter-jdbc</artifactId>       </dependency>       <!-- 添加druid数据源坐标 -->       <dependency>           <groupId>com.alibaba</groupId>           <artifactId>druid-spring-boot-starter</artifactId>           <version>1.1.10</version>       </dependency>       <!-- 添加AOP坐标 -->       <dependency>           <groupId>org.springframework.boot</groupId>           <artifactId>spring-boot-starter-aop</artifactId>       </dependency>   </dependencies></project>

动态数据源配置

这里使用的数据源为druid，实现数据源之间的切换用@DataSource自定义注解，配置Aop进行切换 application.yml 配置文件。

spring:    datasource:        type: com.alibaba.druid.pool.DruidDataSource        druid:          xiaobin-master: # 主数据源            driverClassName: com.mysql.jdbc.Driver            username: root            password: root            url: jdbc:mysql://localhost:3306/master_test?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8          xiaobin-slave: # 从数据源            driverClassName: com.mysql.jdbc.Driver            username: root            password: root            url: jdbc:mysql://localhost:3306/slave_test?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8mybatis: mapper-locations: classpath:mapper/*.xml

多数据源配置类

@Configuration@Componentpublic class DynamicDataSourceConfig {    @Bean    @ConfigurationProperties("spring.datasource.druid.xiaobin-master")    public DataSource  xiaobinMasterDataSource(){        return DruidDataSourceBuilder.create().build();    }    @Bean    @ConfigurationProperties("spring.datasource.druid.xiaobin-slave")    public DataSource  xiaobinSlaveDataSource(){        return DruidDataSourceBuilder.create().build();    }    @Bean    @Primary    public DynamicDataSource dataSource(DataSource xiaobinMasterDataSource, DataSource xiaobinSlaveDataSource) {        Map<Object, Object> targetDataSources = new HashMap<>();        targetDataSources.put("xiaobin-master",xiaobinMasterDataSource);        targetDataSources.put("xiaobin-slave", xiaobinSlaveDataSource);        return new DynamicDataSource(xiaobinMasterDataSource, targetDataSources);    }}

动态数据源切换类

public class DynamicDataSource  extends AbstractRoutingDataSource {    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {        super.setDefaultTargetDataSource(defaultTargetDataSource);        super.setTargetDataSources(targetDataSources);        super.afterPropertiesSet();    }    @Override    protected Object determineCurrentLookupKey() {        return getDataSource();    }    public static void setDataSource(String dataSource) {        contextHolder.set(dataSource);    }    public static String getDataSource() {        return contextHolder.get();    }    public static void clearDataSource() {        contextHolder.remove();    }}

自定义@DataSource注解

在需要切换数据的Dao添加此注解

/** * 备注：自定义数据源选择注解 **/@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface DataSource {    String name() default "";}

Aop切面类配置

@Aspect@Componentpublic class DataSourceAspect {    @Pointcut("@annotation(com.xiaobin.annotation.DataSource)")    public void dataSourcePointCut() {    }    @Around("dataSourcePointCut()")    public Object around(ProceedingJoinPoint point) throws Throwable {        MethodSignature signature = (MethodSignature) point.getSignature();        Method method = signature.getMethod();        DataSource dataSource = method.getAnnotation(DataSource.class);        if(dataSource == null){            DynamicDataSource.setDataSource("xiaobin-master");        }else {            DynamicDataSource.setDataSource(dataSource.name());        }        try {            return point.proceed();        } finally {            DynamicDataSource.clearDataSource();        }    }}

启动配置注解信息，重要（不然运行会报错）

@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class})@MapperScan(basePackages = "com.xiaobin.mapper")@Import({DynamicDataSourceConfig.class})public class StartApp {    public static void main(String[] args) {        SpringApplication.run(StartApp.class);    }}

测试controller

@RestController@RequestMappingpublic class UserController {    @Autowired    private UserMapper userMapper;    @GetMapping("/{name}/list")    public List<TUser> list(@PathVariable("name")String name){        if(name.equals("master")){            return userMapper.queryAllWithMaster();        }else{            return userMapper.queryAllWithSlave();        }    }}

效果图

更具路径传值，进行主从数据源切换.