springboot通过aop实现多数据源动态切换

springboot实现多数据源动态切换（Druid连接池）
1：引入依赖
连接池
切面

2：配置yml
spring:
datasource:
druid:
db1:
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT
username: root
password: root
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
# 打开PSCache，并且指定每个连接上PSCache的大小
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall’用于防火墙，此处是filter修改的地方
filters:
commons-log.connection-logger-name: stat,wall,log4j
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
useGlobalDataSourceStat: true
db2:
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/dcmonitor?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT
username: root
password: root
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
# 打开PSCache，并且指定每个连接上PSCache的大小
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall’用于防火墙，此处是filter修改的地方
filters:
commons-log.connection-logger-name: stat,wall,log4j
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
useGlobalDataSourceStat: true
3：配置数据源
/**

• 多数据源配置类 配置了两个数据源
  /
  @Configuration
  public class DataSourceConfig {
  /*

  • 从配置文件配置数据源
  • @return
    */
    @Bean(name = “datasource1”)
    @ConfigurationProperties(prefix = “spring.datasource.druid.db1”) // application.properteis中对应属性的前缀
    public DataSource dataSource1() {
    // return DataSourceBuilder.create().build();
    return new DruidDataSource();
    }

  /**

  • 从配置文件配置数据源
  • @return
    */
    @Bean(name = “datasource2”)
    @ConfigurationProperties(prefix = “spring.datasource.druid.db2”) // application.properteis中对应属性的前缀
    public DataSource dataSource2() {
    // return DataSourceBuilder.create().build();
    return new DruidDataSource();
    }
    @Bean(name = “datasource3”)
    @ConfigurationProperties(prefix = “spring.datasource.druid.db3”) // application.properteis中对应属性的前缀
    public DataSource dataSource3() {
    // return DataSourceBuilder.create().build();
    return new DruidDataSource();
    }

  /**

  • 动态数据源 进行数据源的切换
  • @return
    */
    @Primary
    @Bean(name = “dynamicDataSource”)
    public DataSource dynamicDataSource() {
    DynamicDataSource dynamicDataSource = new DynamicDataSource();
    // 默认数据源
    dynamicDataSource.setDefaultTargetDataSource(dataSource1());
    // 配置多数据源
    Map<Object, Object> dsMap = new HashMap();
    dsMap.put(“datasource1”, dataSource1());
    dsMap.put(“datasource2”, dataSource2());
    dsMap.put(“datasource3”, dataSource3());
    //将多数据源添加到数据源池中
    dynamicDataSource.setTargetDataSources(dsMap);
    return dynamicDataSource;
    }

  /**

  • 通过动态数据源配置sqlsessionfactory
  • @param dynamicDataSource
  • @return
  • @throws Exception
    /
    @Bean
    public SqlSessionFactory sqlSessionFactory(@Qualifier(“dynamicDataSource”) DataSource dynamicDataSource) throws Exception {
    SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
    factoryBean.setDataSource(dynamicDataSource);
    factoryBean.setTypeAliasesPackage(“com.trs.bigscreen.mapper”);
    factoryBean.setMapperLocations(
    new PathMatchingResourcePatternResolver().getResources("classpath:mapping/.xml"));
    return factoryBean.getObject();
    }

  /**

  • 通过动态数据源配置sqlsessionTemplate
  • @param sqlSessionFactory
  • @return
  • @throws Exception
    */
    @Bean
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory){
    return new SqlSessionTemplate(sqlSessionFactory);
    }

  /**

  • 配置事务管理器
  • @param dynamicDataSource
  • @return
    */
    @Bean
    public DataSourceTransactionManager transactionManager(@Qualifier(“dynamicDataSource”) DataSource dynamicDataSource){
    return new DataSourceTransactionManager(dynamicDataSource);

  }
  }
  4：创建动态数据源获取类
  public class DynamicDataSource extends AbstractRoutingDataSource {
  @Override
  protected Object determineCurrentLookupKey() {
  System.out.println(“数据源为”+DataSourceContextHolder.getDB());
  return DataSourceContextHolder.getDB();
  }
  }
  5：创建数据源管理切换类
  public class DataSourceContextHolder {

  /**

  • 默认数据源
    */
    public static final String DEFAULT_DS = “datasource1”;

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

  // 设置数据源名
  public static void setDB(String dbType) {
  System.out.println(“切换到{”+dbType+"}数据源");
  contextHolder.set(dbType);
  }

  // 获取数据源名
  public static String getDB() {
  return (contextHolder.get());
  }

  // 清除数据源名
  public static void clearDB() {
  contextHolder.remove();
  }
  }
  6：Druid配置监控
  //Druid监控配置
  @Configuration
  public class DruidMoniterConfig {
  //1、配置一个管理后台的Servlet
  @Bean
  public ServletRegistrationBean statViewServlet() {
  ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), “/druid/*”);
  Map<String, String> initParams = new HashMap<>();
  initParams.put(“loginUsername”, “admin”);
  initParams.put(“loginPassword”, “admin”);
  initParams.put(“allow”, “”);//默认就是允许所有访问
  // initParams.put(“deny”, “192.168.15.21”);//黑名单的IP

   bean.setInitParameters(initParams);
   return bean;
  

  }

  //2、配置一个web监控的filter
  @Bean
  public FilterRegistrationBean webStatFilter() {
  FilterRegistrationBean bean = new FilterRegistrationBean();
  bean.setFilter(new WebStatFilter());

   Map<String, String> initParams = new HashMap<>();
   initParams.put("exclusions", "*.js,*.css,/druid/*");
  
   bean.setInitParameters(initParams);
  
   bean.setUrlPatterns(Arrays.asList("/*"));
  
   return bean;
  

  }

}
7：定义注解用于指定数据源
/**

• 数据源切换注解
  /
  @Retention(RetentionPolicy.RUNTIME)
  @Target({ElementType.METHOD,ElementType.TYPE})
  public @interface DS {
  String value() default “datasource1”;
  }
  8：定义切面进行动态切换
  /*

• 动态数据源切面
  */
  @Order(0) // Spring的事务与数据源是绑定的。也就说，如果你开启了事务，那么数据源已经绑定了。那么这个时候，你在去切换数据源就无效了。也就是说要想有效，那么久要在事务开启之前就把数据源切换好。
  @Aspect
  @Component
  public class DynamicDataSourceAspect {

  @Before("@annotation(ds)")
  public void beforeSwitchDS(JoinPoint point,DS ds){
  System.out.println(“进入切面了…”);
  //获得当前访问的class
  Class<?> className = point.getTarget().getClass();
  //获得访问的方法名
  String methodName = point.getSignature().getName();
  //得到方法的参数的类型
  Class[] argClass = ((MethodSignature)point.getSignature()).getParameterTypes();
  String dataSource = DataSourceContextHolder.DEFAULT_DS;
  try {
  // 得到访问的方法对象
  Method method = className.getMethod(methodName, argClass);
  // 判断是否存在@DS注解
  if (method.isAnnotationPresent(DS.class)) {
  DS annotation = method.getAnnotation(DS.class);
  // 取出注解中的数据源名
  dataSource = annotation.value();
  }
  } catch (Exception e) {
  e.printStackTrace();
  }
  // 切换数据源
  DataSourceContextHolder.setDB(dataSource);
  }

  @After("@annotation(com.trs.bigscreen.annotation.DS)")
  public void afterSwitchDS(JoinPoint point){
  DataSourceContextHolder.clearDB();
  }
  }
  9：用法