springboot集成mongodb实现动态切换数据源

南方老张爱生活 發表於 2020-4-9 08:55:00

springboot集成mongodb实现动态切换数据源

主要实现原理，利用spring的aop 在切入点执行db操作之前将数据库切换：
本例子采用aop在controller进行拦截拦截到MongoTemplate.class 切换数据源后重新放回去，处理完成后将相关数据源的template删除
 
引入mongodb相关依赖
<div class="cnblogs_code">
<pre><dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-mongodb</artifactId>
 </dependency>

 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-aop</artifactId>
 </dependency></pre>
</div>
<pre>多数据源MultiMongoTemplate</pre>
<div class="cnblogs_code">
<pre>import com.mongodb.client.MongoDatabase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.MongoTemplate;

public class MultiMongoTemplate extends MongoTemplate {
private Logger logger= LoggerFactory.getLogger(MultiMongoTemplate.class);
//用来缓存当前MongoDbFactory
private static ThreadLocal<MongoDbFactory> mongoDbFactoryThreadLocal;
public MultiMongoTemplate(MongoDbFactory mongoDbFactory){
 super(mongoDbFactory);
 if(mongoDbFactoryThreadLocal==null) {
 mongoDbFactoryThreadLocal = new ThreadLocal<>();
 }
}

public void setMongoDbFactory(MongoDbFactory factory){
 mongoDbFactoryThreadLocal.set(factory);
}

public void removeMongoDbFactory(){
 mongoDbFactoryThreadLocal.remove();
}

@Override
public MongoDatabase getDb() {
 return mongoDbFactoryThreadLocal.get().getDb();
}
}</pre>
</div>
aop 切片类MongoSwitch
<div class="cnblogs_code">
<pre>import cn.net.topnet.topfs.dynamicdb.MultiMongoTemplate;
import com.mongodb.MongoClient;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.SimpleMongoClientDbFactory;
import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;

@Component
@Aspect
public class MongoSwitch {
private final Logger logger = LoggerFactory.getLogger(MongoSwitch.class);

@Autowired
private MongoDbFactory mongoDbFactory;
private Map<String,MongoDbFactory> templateMuliteMap=new HashMap<>();
//获取配置文件的副本集连接
@Value("${spring.data.mongodb.uri}")
private String uri;

@Pointcut("execution(* cn.net.topnet.topfs.controller..*.*(..))")
public void routeMongoDB() {

}

@Around("routeMongoDB()")
public Object routeMongoDB(ProceedingJoinPoint joinPoint) {
 Object result = null;
 HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();

 //获取需要访问的项目数据库
 String dbName = request.getRequestURI().trim().substring(1);
 String name = joinPoint.getSignature().getName();
 Object o = joinPoint.getTarget();
 Field[] fields = o.getClass().getDeclaredFields();
 MultiMongoTemplate mongoTemplate = null;

 try {
 for (Field field : fields) {
 field.setAccessible(true);
 Object fieldObject = field.get(o);
 Class fieldclass = fieldObject.getClass();
 //找到Template的变量
 if (fieldclass == MongoTemplate.class || fieldclass == MultiMongoTemplate.class) {
 //查找项目对应的MongFactory
 SimpleMongoClientDbFactory simpleMongoClientDbFactory=(SimpleMongoClientDbFactory)templateMuliteMap.get(dbName);
 //实例化
 if(simpleMongoClientDbFactory==null){ 　　　　　　　　　　　　　　　　//替换数据源
 simpleMongoClientDbFactory = new SimpleMongoClientDbFactory(this.uri.replace("#",dbName));
 templateMuliteMap.put(dbName,simpleMongoClientDbFactory);
 }
 //如果第一次，赋值成自定义的MongoTemplate子类
 if(fieldclass==MongoTemplate.class){
 mongoTemplate = new MultiMongoTemplate(simpleMongoClientDbFactory);
 }else if(fieldclass==MultiMongoTemplate.class){
 mongoTemplate=(MultiMongoTemplate)fieldObject;
 }
 //设置MongoFactory
 mongoTemplate.setMongoDbFactory(simpleMongoClientDbFactory);
 //重新赋值
 field.set(o, mongoTemplate);
 break;
 }
 }
 try {
 result = joinPoint.proceed();
 //清理ThreadLocal的变量
 mongoTemplate.removeMongoDbFactory();
 } catch (Throwable t) {
 logger.error("", t);
 }
 } catch (Exception e) {
 logger.error("", e);
 }

 return result;
}
}</pre>
</div>
yml配置
<div class="cnblogs_code">
<pre>spring:
data:
mongodb:
 uri: mongodb://bobo:bobo123@192.168.3.114:27017,192.168.3.114:27018,192.168.3.114:27019/#?connect=replicaSet&slaveOk=true&replicaSet=myrs</pre>
</div>
测试controller
<div class="cnblogs_code">
<pre> @GetMapping("/{dbName}")
publicvoid testMongoTemplate(@PathVariable("dbName") String dbName){

 Query query = new Query();
 query.addCriteria(Criteria.where("display").is("测试"));
 // spring会将查询到的结果自动映射
 Domains one = mongoTemplate.findOne(query, Domains.class);

 System.out.println(one);
}</pre>
</div>
  
来源：https://www.cnblogs.com/jiawen010/p/12664494.html

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springboot集成mongodb实现动态切换数据源