Springboot+aop实现配置多数据源的示例代码
作者：王五周八
本文介绍了如何使用SpringAOP和注解实现动态数据源切换,通过自定义注解和ThreadLocal存储数据上下文信息,重写AbstractRoutingDataSource类并使用自定义切面来实现动态数据源的切换,感兴趣的可以了解一下
前言
这是我司在对于动态数据源的一个处理方法，采用动态加载数据库信息实现动态数据源的切换。通过使用Spring AOP + 注解来替换当前线程ThreadLocal中的值，并且通过重写AbstractRoutingDataSource类重写determineCurrentLookUpKey()方法，实现动态数据源切换，满足功能实现的代码0侵入性，并且高度解耦，实现可拔插功能效果
1、添加依赖（本项目是一个springboot项目）
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>2.2.0</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>dynamic-datasource-spring-boot-starter</artifactId>
<version>3.5.2</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-core</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.9</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.22</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.32</version>
<scope>runtime</scope>
</dependency>
2、定义数据库类型枚举类(enum)
/**
* 数据库配置名字字段
* @author zh
* @data 17点14分
*
*/
public enum DBTypeEnum {
cs1db("cs1-db"), cs2db("cs2-db");
private String value;
DBTypeEnum(String value) {
this.value = value;
}
public String getValue() {
return value;
}
}
此枚举主要是用于简化if-else语句。
3、定义注解(annotation)
/**
* @author zh
* @data 17点18分
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface DataSourceSwitch {
/****
* 顺便设置下默认数据源
* @return
*/
DBTypeEnum value() default DBTypeEnum.cs1db;
}
定义DataSourceSwitch注解，默认数据源为cs1db(数据库一)。
4、编写ThreadLocal存储数据上下文信息
/**
* @author zh
*/
public class DbContextHolder {
private static final ThreadLocal contextHolder = new ThreadLocal<>();
/**
* 设置数据源
* @param dbTypeEnum
*/
public static void setDbType(DBTypeEnum dbTypeEnum) {
contextHolder.set(dbTypeEnum.getValue());
}
/**
* 取得当前数据源
* @return
*/
public static String getDbType() {
return (String) contextHolder.get();
}
/**
* 清除上下文数据
*/
public static void clearDbType() {
contextHolder.remove();
}
}
工具类DbContextHolder用于存储数据名上下文。
5、获取数据源信息
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
* @author zh
*/
public class DynamicDataSource extends AbstractRoutingDataSource {
/**
* 取得当前使用哪个数据源
* @return
*/
@Override
protected Object determineCurrentLookupKey() {
return DbContextHolder.getDbType();
}
}
工具类DynamicDataSource继承AbstractRoutingDataSource重写determineCurrentLookupKey（）方法，从工具类DbContextHolder中获取当前数据源信息。
6、自定义切面(Aspect)
/**
* @author zh
* 数据源AOP注解实现
*/
@Component
@Aspect
@Order(-100)
public class DataSourceSwitchAspect {
private Logger log= LoggerFactory.getLogger(DataSourceSwitchAspect.class);
@Pointcut("execution(* com.zh.cn.business.cs1db..*.*(..))")
private void cs1dbAspect() {
}
@Pointcut("execution(* com.zh.cn.business.cs2db..*.*(..))")
private void cs2dbAspect() {
}
@Before( "cs1dbAspect()" )
public void basic(JoinPoint joinPoint) {
//log.info("切换到cs1db 数据源...");
setDataSource(joinPoint, DBTypeEnum.cs1db);
}
@Before("cs2dbAspect()" )
public void order (JoinPoint joinPoint) {
//log.info("切换到cs2db 数据源...");
setDataSource(joinPoint,DBTypeEnum.cs2db);
}
/**
* 添加注解方式,如果有注解优先注解,没有则按传过来的数据源配置
* @param joinPoint
* @param dbTypeEnum
*/
private void setDataSource(JoinPoint joinPoint, DBTypeEnum dbTypeEnum) {
MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
DataSourceSwitch dataSourceSwitch = methodSignature.getMethod().getAnnotation(DataSourceSwitch.class);
if (Objects.isNull(dataSourceSwitch) || Objects.isNull(dataSourceSwitch.value())) {
DbContextHolder.setDbType(dbTypeEnum);
}else{
// log.info("根据注解来切换数据源,注解值为:"+dataSourceSwitch.value());
switch (dataSourceSwitch.value().getValue()) {
case "cs1-db":
DbContextHolder.setDbType(DBTypeEnum.cs1db);
break;
case "cs2-db":
DbContextHolder.setDbType(DBTypeEnum.cs2db);
break;
default:
DbContextHolder.setDbType(dbTypeEnum);
}
}
}
}
通过springAop自定义切面，切入点在* com.zh.cn.business.cs2db..*.*(..))，表示切入点在com.zh.cn.business.cs2db包下的任意子包、任意方法和任意返回值，并通过setDataSource（）方法设置工具类DbContextHolder中数据源信息。
7、配置数据源信息
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import com.baomidou.mybatisplus.generator.config.rules.DbType;
import com.zh.cn.Utils.DynamicDataSource;
import com.zh.cn.constants.DBTypeEnum;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.type.JdbcType;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
* 加载DataSource
*/
@Configuration
@MapperScan({"com.zh.cn.**.mapper"})
public class MybatisPlusConfig {
/**
* mapper-plus分页插件<br>
* 文档：http://mp.baomidou.com<br>
*/
/* @Bean
public PaginationInterceptor paginationInterceptor() {
PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
//paginationInterceptor.setLocalPage(true);// 开启 PageHelper 的支持
return paginationInterceptor;
}*/
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
//乐观锁
interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
return interceptor;
}
@Bean(name = "cs1db")
@ConfigurationProperties(prefix = "spring.datasource.druid.cs1-db" )
public DataSource cs1db () {
return DruidDataSourceBuilder.create().build();
}
@Bean(name = "cs2db")
@ConfigurationProperties(prefix = "spring.datasource.druid.cs2-db" )
public DataSource cs2db () {
return DruidDataSourceBuilder.create().build();
}
/**
* 动态数据源配置
* @return
*/
@Bean
@Primary
public DataSource multipleDataSource (@Qualifier("cs1db") DataSource cs1db,
@Qualifier("cs2db") DataSource cs2db){
DynamicDataSource dynamicDataSource = new DynamicDataSource();
Map< Object, Object > targetDataSources = new HashMap<>();
targetDataSources.put(DBTypeEnum.cs1db.getValue(), cs1db );
targetDataSources.put(DBTypeEnum.cs2db.getValue(), cs2db);
dynamicDataSource.setTargetDataSources(targetDataSources);
dynamicDataSource.setDefaultTargetDataSource(cs1db);//指定默认
return dynamicDataSource;
}
@Bean("sqlSessionFactory")
public SqlSessionFactory sqlSessionFactory() throws Exception {
MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
sqlSessionFactory.setDataSource(multipleDataSource(cs1db(),cs2db()));
sqlSessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/*/*Mapper.xml"));
MybatisConfiguration configuration = new MybatisConfiguration();
configuration.setJdbcTypeForNull(JdbcType.NULL);
configuration.setMapUnderscoreToCamelCase(true);
configuration.setCacheEnabled(false);
sqlSessionFactory.setConfiguration(configuration);
sqlSessionFactory.setPlugins(new Interceptor[]{
mybatisPlusInterceptor()
});
return sqlSessionFactory.getObject();
}
}
通过覆盖默认的DataSource进行加载动态数据源的配置信息，通过**multipleDataSource（）方法设置数据源，最后通过sqlSessionFactory（）**设置数据源的最终加载
8、编写配置文件
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
cs1-db:
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/short-chain?useUnicode=true&characterEncoding=UTF-8
username: root
password:
initialSize: 10
minIdle: 20
maxActive: 100
maxWait: 60000
cs2-db:
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/short-chain?useUnicode=true&characterEncoding=UTF-8
username: root
password:
initialSize: 10
minIdle: 20
maxActive: 100
maxWait: 60000
maxActive: 100
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