思路还是继承 org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
通过重写父类方法：protected Object determineCurrentLookupKey() 来实现数据源的动态切换。通过注解在方法上实现方法内数据源的动态切换，方法结束后恢复默认数据源。
这个demo我用的springboot 2.1.7
demo项目下载： https://gitee.com/zhuhongliang/springboot_multi_datasource_demo.git
首先一定要在启动类加上exclude = DataSourceAutoConfiguration.class
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@MapperScan(basePackages = "com.zhl.multi_data_source_demo.dao")
public class MultiDataSourceDemoApplication implements ApplicationRunner {
public static void main(String[] args) {
SpringApplication.run(MultiDataSourceDemoApplication.class, args);
}
@Autowired
private ApplicationContext applicationContext;
@Override
public void run(ApplicationArguments args){
//系统启动会自动运行这段代码，用以测试
Service service = (Service) applicationContext.getBean("service");
service.contextLoads2();
service.contextLoads21();
}
}
否则会报错：The dependencies of some of the beans in the application context form a cycle:
DataSource.java：
import java.lang.annotation.*;
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
String value() default DataSource.master;
//主从数据源Bean的名字不能瞎写，否则数据源切换不成功
String master = "masterDataSource";
String slave = "slaveDataSource";
}
DataSourceAspect.java：
import org.aspectj.lang.annotation.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.aspectj.lang.JoinPoint;
import java.lang.reflect.Method;
@Aspect
@Order(1)
@Component
public class DataSourceAspect {
private static Logger logger = LoggerFactory.getLogger(DataSourceAspect.class);
/**
* @within匹配类上的注解
* @annotation匹配方法上的注解
*/
@Pointcut(value = "@within(com.zhl.multi_data_source_demo.DataSource)||@annotation(com.zhl.multi_data_source_demo.DataSource)")
public void pointcut(){}
@Before(value = "pointcut()")
public void beforeOpt(JoinPoint joinPoint) {
Object target = joinPoint.getTarget();
Class<?> clazz = target.getClass();
Method[] methods = clazz.getMethods();
DataSource annotation = null;
for (Method method : methods) {
if (joinPoint.getSignature().getName().equals(method.getName())) {
annotation = method.getAnnotation(DataSource.class);
if (annotation == null) {
annotation = joinPoint.getTarget().getClass().getAnnotation(DataSource.class);
if (annotation == null) {
return;
}
}
}
}
String dataSourceName = annotation.value();
DataSourceHolder.setDataSource(dataSourceName);
logger.info("切到" + dataSourceName + "数据库");
}
@After(value="pointcut()")
public void afterOpt(){
DataSourceHolder.clearDataSource();
logger.info("切回默认数据库");
}
}
DataSourceConfig.java：
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
@Configuration
public class DataSourceConfig {
@Bean(name="masterDataSource")//主数据源Bean
@ConfigurationProperties(prefix = "spring.datasource.master")
public DataSource masterDataSource(){
return DataSourceBuilder.create().build();
}
@Bean(name="slaveDataSource")//从数据源Bean
@ConfigurationProperties(prefix = "spring.datasource.slave")
public DataSource slaveDataSource(){
return DataSourceBuilder.create().build();
}
@Primary//这个注解千万不能少
@Bean(name = "dynamicDataSource")
public DynamicDataSource dataSource(@Qualifier("masterDataSource") DataSource masterDataSource, @Qualifier("slaveDataSource") DataSource slaveDataSource) {
Map<Object, Object> targetDataSources = new HashMap<>();
targetDataSources.put("masterDataSource", masterDataSource);//key千万不能写错
targetDataSources.put("slaveDataSource", slaveDataSource);//key千万不能写错
return new DynamicDataSource(masterDataSource, targetDataSources);
}
/*这个bean可以不写，网上有很多demo都写了这个
@Bean("sqlSessionFactoryBean")
public SqlSessionFactoryBean sqlSessionFactoryBean(@Qualifier("dynamicDataSource") DynamicDataSource dynamicDataSource) throws IOException {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dynamicDataSource);
sqlSessionFactoryBean.setTypeAliasesPackage("com.zhl.multi_data_source_demo.dao");
return sqlSessionFactoryBean;
}*/
}
DataSourceHolder.java：
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* 封装的对数据源进行操作的类：
*/
public class DataSourceHolder {
private static Logger logger = LoggerFactory.getLogger(DataSourceAspect.class);
//线程 本地环境
private static final ThreadLocal<String> dataSources = new InheritableThreadLocal();
//设置数据源
public static void setDataSource(String datasource) {
logger.info("设置数据源={}", datasource);
dataSources.set(datasource);
}
//获取数据源
public static String getDataSource() {
return dataSources.get();
}
//清除数据源
public static void clearDataSource() {
dataSources.remove();
}
}
DynamicDataSource.java：
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import java.util.Map;
public class DynamicDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DataSourceHolder.getDataSource();
}
public DynamicDataSource(javax.sql.DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources)
{
super.setDefaultTargetDataSource(defaultTargetDataSource);
super.setTargetDataSources(targetDataSources);
super.afterPropertiesSet();
}
}
实际方法调用的时候只需要加上注解就行了。
@DataSource(DataSource.slave)
public void contextLoads2() {
System.out.println(JSONArray.toJSONString(userinfoDAO.findAll2()));
}
demo项目下载： https://gitee.com/zhuhongliang/springboot_multi_datasource_demo.git
