序：數據源動態切換流程圖如下：
1:pom.xml文件依賴聲明
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.4</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.12</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
2：application.yml配置文件
配置多個數據源信息
server:
port: 9000
dynamic:
datasource:
ds1: # 數據源1
jdbc-url: jdbc:mysql://localhost:3306/test1?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8
username: root
password: 123456
driver-class-name: com.mysql.cj.jdbc.Driver
ds2: # 數據源2
jdbc-url: jdbc:mysql://localhost:3306/test2?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=GMT%2B8
username: root
password: 123456
driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
mapper-locations: classpath:mapper/*.xml
configuration:
map-underscore-to-camel-case: true
3：數據源的配置到Spring管理
/**
* description 數據源配置類
*
* @author liekkas 2021/08/21 12:33
*/
@Configuration
public class DynamicDataSourceConfig {
@Bean(name = "dataSource1")
@ConfigurationProperties(prefix = "dynamic.datasource.ds1")
public DataSource dateSource1() {
return DataSourceBuilder.create().build();
}
@Bean(name = "dataSource2")
@ConfigurationProperties(prefix = "dynamic.datasource.ds2")
public DataSource dateSource2() {
return DataSourceBuilder.create().build();
}
@Bean
@Primary
public DynamicRoutingDataSource dynamicDataSource() {
DynamicRoutingDataSource dynamicRoutingDataSource = new DynamicRoutingDataSource();
//設置默認的數據源
dynamicRoutingDataSource.setDefaultTargetDataSource(dateSource1());
Map<Object, Object> targetDataSources = new HashMap<>(4);
targetDataSources.put("dataSource1", dateSource1());
targetDataSources.put("dataSource2", dateSource2());
//設置數據源
dynamicRoutingDataSource.setTargetDataSources(targetDataSources);
dynamicRoutingDataSource.afterPropertiesSet();
DynamicDataSourceContextHolder.dataSourceSet.addAll(targetDataSources.keySet());
return dynamicRoutingDataSource;
}
}
注意：@ConfigurationProperties注解的prefix的值和配置文件application.yml必須要保持一致
3:配置數據源上下文
我們需要新建一個數據源上下文，用戶記錄當前線程使用的數據源是什么，以及記錄所有注冊成功的數據源的集合。對於線程級別的私有變量，我們首先ThreadLocal來實現。
/**
* description 設置當前線程數據源上下文類
*
* @author liekkas 2021/08/21 12:37
*/
public class DynamicDataSourceContextHolder {
private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceContextHolder.class);
/**
* 存儲已經注冊的數據源的key
*/
public static Set<Object> dataSourceSet = new HashSet<>();
/**
* 線程級別的私有變量
*/
private static final ThreadLocal<String> HOLDER = new ThreadLocal<>();
public static String getDataSourceRouterKey() {
return HOLDER.get();
}
public static void setDataSourceRouterKey(String dataSourceRouterKey) {
logger.info("當前數據源正在切換中......");
HOLDER.set(dataSourceRouterKey);
}
/**
* 設置數據源之前一定要先移除
*/
public static void removeDataSourceRouterKey() {
HOLDER.remove();
}
/**
* 判斷指定dataSource當前是否存在
*
* @param dataSource dataSource
* @return boolean
*/
public static boolean isExistDataSource(Object dataSource) {
return dataSourceSet.contains(dataSource);
}
}
4:動態數據源路由
第三步我們以及新建了數據源上下文，用於存儲我們當前線程的數據源，那么怎么通知spring用當前的數據源，spring提供一個接口，名為AbstractRoutingDataSource的抽象類，我們只需要重寫determineCurrentLookupKey方法就可以，這個方法看名字就知道，就是返回當前線程的數據源，那我們只需要從我們剛剛的數據源上下文中取出當前數據源即可
/**
* description 數據源動態路由
*
* @author liekkas 2021/08/21 12:39
*/
public class DynamicRoutingDataSource extends AbstractRoutingDataSource {
private static final Logger logger = LoggerFactory.getLogger(DynamicRoutingDataSource.class);
@Override
protected Object determineCurrentLookupKey() {
String dataSourceName = DynamicDataSourceContextHolder.getDataSourceRouterKey();
logger.info("當前數據源是:{}", dataSourceName);
return DynamicDataSourceContextHolder.getDataSourceRouterKey();
}
}:
5：數據源動態切換注解
/**
* description 動態切換數據源注解
* 該注解可以同時作用於類和方法上，如果類和方法注解同時存在，則方法的注解優先級高於類上的注解優先級
* 也就是說類和方法同時存在該注解的話，則會使用方法的數據源
*
* @author liekkas 2021/08/21 12:40
*/
@Target({ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
String value() default "dataSource1";
}:
6：利用aop實現數據源動態切換
/**
* description 動態切換數據源切面
*
* @author liekkas 2021/08/21 12:42
*/
@Aspect
@Component
@Order(-1)
public class DynamicDataSourceAspect {
private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAspect.class);
/**
* 同時攔截標注DataSource的注解類上或者方法
*/
@Pointcut(value = "@within(com.liekkas.config.datasource.DataSource) || @annotation(com.liekkas.config.datasource.DataSource)")
public void datasource() {
}
@Before("datasource()")
public void changeDataSource(JoinPoint joinPoint) {
Class<?> klass = joinPoint.getTarget().getClass();
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
Method method = signature.getMethod();
DataSource dataSource;
if (method.isAnnotationPresent(DataSource.class)) {
dataSource = method.getAnnotation(DataSource.class);
} else {
dataSource = klass.getAnnotation(DataSource.class);
}
//判斷注解中的數據源是否在已注冊的數據源中
if (DynamicDataSourceContextHolder.isExistDataSource(dataSource.value())) {
DynamicDataSourceContextHolder.setDataSourceRouterKey(dataSource.value());
logger.info("數據源設置為 > {}", dataSource.value());
} else {
throw new RuntimeException("數據源[" + dataSource.value() + "]不存在");
}
}
@After("datasource()")
public void restoreDataSource() {
DynamicDataSourceContextHolder.removeDataSourceRouterKey();
}
}
7：測試
7.1：controller
/**
* description
*
* @author liekkas 2021/01/09 15:47
*/
@RestController
public class PersonController {
@Resource
private PersonService personService;
@GetMapping("person")
public List<Person> findPerson() {
return personService.findPerson();
}
@GetMapping("student")
public List<Student> findStudent() {
return personService.findStudent();
}
}
7.2: service
public interface PersonService {
/**
* findPerson
*
* @return list
*/
List<Person> findPerson();
/**
* findStudent
*
* @return list
*/
List<Student> findStudent();
}
7.3: serviceImpl
@Service
@DataSource("dataSource1")
public class PersonServiceImpl implements PersonService {
@Resource
private PersonMapper personMapper;
@Override
public List<Person> findPerson() {
return personMapper.findPerson();
}
@Override
@DataSource("dataSource2")
public List<Student> findStudent() {
return personMapper.findStudent();
}
}
由於篇幅關系，mapper以及實體類不再描述
測試接口調用
至此數據源動態切換已經完成。