MyBatis 多数据源读写分离（注解实现）

àì夳堔傛蜴生んèń 2021-07-31 20:48 481阅读 0赞

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作者 | hy\_xiaobin

来源 | juejin.im/post/5d8705e65188253f4b629f47

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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，喜喜），表结构

表名  t\_user

![640?wx\_fmt=jpeg][640_wx_fmt_jpeg 1]

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 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>
           
           <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.springframework.boot</groupId>
               <artifactId>spring-boot-starter-test</artifactId>
           </dependency>
           
           <dependency>
               <groupId>org.projectlombok</groupId>
               <artifactId>lombok</artifactId>
               <version>${lombox.version}</version>
           </dependency>
           
           <dependency>
               <groupId>org.mybatis.spring.boot</groupId>
               <artifactId>mybatis-spring-boot-starter</artifactId>
               <version>${mybatis.version}</version>
           </dependency>
           
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
           </dependency>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-jdbc</artifactId>
           </dependency>
           
           <dependency>
               <groupId>com.alibaba</groupId>
               <artifactId>druid-spring-boot-starter</artifactId>
               <version>1.1.10</version>
           </dependency>
           
           <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:
                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:
                driverClassName: com.mysql.jdbc.Driver
                username: root
                password: root
                url: jdbc:mysql://localhost:3306/slave_test?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8
    mybatis:
      mapper-locations: classpath:mapper/*.xml

#### 多数据源配置类 ####

@Configuration
    @Component
    public 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

package com.xiaobin.annotation;
    
    import java.lang.annotation.*;
    
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface DataSource {
        String name() default "";
    }

#### Aop切面类配置 ####

@Aspect
    @Component
    public 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
    @RequestMapping
    public 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

![640?wx\_fmt=png][640_wx_fmt_png]

![640?wx\_fmt=png][640_wx_fmt_png 1]

#### 目录结构 ####

![640?wx\_fmt=png][640_wx_fmt_png 2]

源码地址（数据库需要自己创建）

https://gitee.com/MyXiaoXiaoBin/learning-to-share/tree/master/mysql\_master\_slave

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\-END-

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