<!--JSON-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-joda</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.module</groupId>
      <artifactId>jackson-module-parameter-names</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.0.11</version>
    </dependency>
    <!--mybatis-->
    <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>1.1.1</version>
    </dependency>
    <!--mapper-->
    <dependency>
      <groupId>tk.mybatis</groupId>
      <artifactId>mapper-spring-boot-starter</artifactId>
      <version>1.1.0</version>
    </dependency>
    <!--pagehelper-->
    <dependency>
      <groupId>com.github.pagehelper</groupId>
      <artifactId>pagehelper-spring-boot-starter</artifactId>
      <version>1.1.0</version>
      <exclusions>
        <exclusion>
          <artifactId>mybatis-spring-boot-starter</artifactId>
          <groupId>org.mybatis.spring.boot</groupId>
        </exclusion>
      </exclusions>
    </dependency>

druid:
  type: com.alibaba.druid.pool.DruidDataSource
  master:
    url: jdbc:mysql://192.168.249.128:3307/db-test?characterEncoding=UTF-8&autoReconnect=true&zeroDateTimeBehavior=convertToNull&useUnicode=true
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: root
    initial-size: 5
    min-idle: 1
    max-active: 100
    test-on-borrow: true
  slave:
    url: jdbc:mysql://192.168.249.128:3317/db-test?characterEncoding=UTF-8&autoReconnect=true&zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: root
    initial-size: 5
    min-idle: 1
    max-active: 100
    test-on-borrow: true

@Configuration
@EnableTransactionManagement
public class DataSourceConfiguration {

  @Value("${druid.type}")
  private Class<? extends DataSource> dataSourceType;

  @Bean(name = "masterDataSource")
  @Primary
  @ConfigurationProperties(prefix = "druid.master")
  public DataSource masterDataSource(){
    return DataSourceBuilder.create().type(dataSourceType).build();
  }

  @Bean(name = "slaveDataSource")
  @ConfigurationProperties(prefix = "druid.slave")
  public DataSource slaveDataSource1(){
    return DataSourceBuilder.create().type(dataSourceType).build();
  }
}

@Configuration
@AutoConfigureAfter({DataSourceConfiguration.class})
public class MybatisConfiguration extends MybatisAutoConfiguration {

  private static Log logger = LogFactory.getLog(MybatisConfiguration.class);

  @Resource(name = "masterDataSource")
  private DataSource masterDataSource;
  @Resource(name = "slaveDataSource")
  private DataSource slaveDataSource;

  @Bean
  public SqlSessionFactory sqlSessionFactory() throws Exception {
    return super.sqlSessionFactory(roundRobinDataSouceProxy());
  }

  public AbstractRoutingDataSource roundRobinDataSouceProxy(){
    ReadWriteSplitRoutingDataSource proxy = new ReadWriteSplitRoutingDataSource();
    Map<Object,Object> targetDataResources = new ClassLoaderRepository.SoftHashMap();
    targetDataResources.put(DbContextHolder.DbType.MASTER,masterDataSource);
    targetDataResources.put(DbContextHolder.DbType.SLAVE,slaveDataSource);
    proxy.setDefaultTargetDataSource(masterDataSource);//默认源
    proxy.setTargetDataSources(targetDataResources);
    return proxy;
  }
}

public class DbContextHolder {

  public enum DbType{
    MASTER,SLAVE
  }

  private static final ThreadLocal<DbType> contextHolder = new ThreadLocal<>();

  public static void setDbType(DbType dbType){
    if(dbType==null)throw new NullPointerException();
    contextHolder.set(dbType);
  }

  public static DbType getDbType(){
    return contextHolder.get()==null?DbType.MASTER:contextHolder.get();
  }

  public static void clearDbType(){
    contextHolder.remove();
  }

}

/**
 * 该注解注释在service方法上，标注为链接slaves库
 * Created by Jason on 2017/3/6.
 */
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface ReadOnlyConnection {
}

@Aspect
@Component
public class ReadOnlyConnectionInterceptor implements Ordered {

  public static final Logger logger = LoggerFactory.getLogger(ReadOnlyConnectionInterceptor.class);

  @Around("@annotation(readOnlyConnection)")
  public Object proceed(ProceedingJoinPoint proceedingJoinPoint,ReadOnlyConnection readOnlyConnection) throws Throwable {
    try {
      logger.info("set database connection to read only");
      DbContextHolder.setDbType(DbContextHolder.DbType.SLAVE);
      Object result = proceedingJoinPoint.proceed();
      return result;
    }finally {
      DbContextHolder.clearDbType();
      logger.info("restore database connection");
    }
  }


  @Override
  public int getOrder() {
    return 0;
  }
}

public class ReadWriteSplitRoutingDataSource extends AbstractRoutingDataSource {

  @Override
  protected Object determineCurrentLookupKey() {
    return DbContextHolder.getDbType();
  }
}

@Table(name = "t_sys_dic_type")
public class DicType extends BaseEntity{

  String code;

  String name;

  Integer status;

  ...
}

public interface DicTypeMapper extends BaseMapper<DicType> {
}

@Service
public class DicTypeService {
  @Autowired
  private DicTypeMapper dicTypeMapper;

  @ReadOnlyConnection
  public List<DicType> getAll(DicType dicType){
    if (dicType.getPage() != null && dicType.getRows() != null) {
      PageHelper.startPage(dicType.getPage(), dicType.getRows());
    }
    return dicTypeMapper.selectAll();
  }

}

@RestController
@RequestMapping("/dictype")
public class DicTypeController {
  @Autowired
  private DicTypeService dicTypeService;

  @RequestMapping(value = "/all")
  public PageInfo<DicType> getALL(DicType dicType){
    List<DicType> dicTypeList = dicTypeService.getAll(dicType);
    return new PageInfo<>(dicTypeList);
  }
}

c.a.d.m.ReadOnlyConnectionInterceptor  : set database connection to read only