由于您是 Spring boot 和 MongoDB 的新手，我为您提供以下详细步骤，以在单个应用程序中连接多个 mongo DB。这是配置和连接多个 mongo DB 的最简单方法之一。希望它会有所帮助（如果是，请不要忘记投票:-)）-
1) 包结构-
2) 创建一个抽象的 MongoDB Config 类 -
package com.akash.mongo.multidb.config;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;
import com.mongodb.MongoCredential;
import com.mongodb.ServerAddress;
/**
* Abstract class for configuring different MongoTemplate for different DB
* @author Akash
*
*/
public abstract class AbstractMongoDbConfig {
private String host;
private String username;
private String password;
private String database;
private int port;
public void setHost(String host) {
this.host = host;
}
public void setUsername(String username) {
this.username = username;
}
public void setPassword(String password) {
this.password = password;
}
public void setDatabase(String database) {
this.database = database;
}
public void setPort(int port) {
this.port = port;
}
public MongoDbFactory mongoDbFactory() {
MongoCredential mongoCredential = MongoCredential.createCredential(username, database, password.toCharArray());
MongoClient mongoClient = new MongoClient(new ServerAddress(host, port), mongoCredential, new MongoClientOptions.Builder().build());
return new SimpleMongoDbFactory(mongoClient, database);
}
public abstract MongoTemplate getMongoTemplate() throws Exception;
}
3) 扩展抽象类为每个数据库创建配置
AmazonDbConfig
package com.akash.mongo.multidb.config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;
/**
* Configuration class for Amazon DB
* @author Akash
*
*/
@Configuration
@ConfigurationProperties(prefix="amazon.mongodb")
@EnableMongoRepositories(basePackages= {"com.akash.mongo.multidb.repository.amazon"}, mongoTemplateRef="amazonMongoTemplate")
public class AmazonDbConfig extends AbstractMongoDbConfig {
private static final Logger logger = LoggerFactory.getLogger(AmazonDbConfig.class);
@Override
@Bean(name="amazonMongoTemplate")
public MongoTemplate getMongoTemplate() throws Exception {
logger.info("Creating MongoTemplate for Amazon DB");
return new MongoTemplate(mongoDbFactory());
}
}
EbayDbConfig
package com.akash.mongo.multidb.config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;
/**
* Configuration class for ebay DB
* @author Akash
*
*/
@Configuration
@ConfigurationProperties(prefix="ebay.mongodb")
@EnableMongoRepositories(basePackages= {"com.akash.mongo.multidb.repository.ebay"}, mongoTemplateRef="ebayMongoTemplate")
public class EbayDbConfig extends AbstractMongoDbConfig {
private static final Logger logger = LoggerFactory.getLogger(EbayDbConfig.class);
@Override
@Bean(name="ebayMongoTemplate")
public MongoTemplate getMongoTemplate() throws Exception {
logger.info("Creating MongoTemplate for Ebay DB");
return new MongoTemplate(mongoDbFactory());
}
}
FlipkartDbConfig
package com.akash.mongo.multidb.config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;
/**
* Configuration class for Flipkart DB
* @author Akash
*
*/
@Configuration
@ConfigurationProperties(prefix="flipkart.mongodb")
@EnableMongoRepositories(basePackages= {"com.akash.mongo.multidb.repository.flipkart"}, mongoTemplateRef="flipkartMongoTemplate")
public class FlipkartDbConfig extends AbstractMongoDbConfig {
private static final Logger logger = LoggerFactory.getLogger(FlipkartDbConfig.class);
@Override
@Primary
@Bean(name="flipkartMongoTemplate")
public MongoTemplate getMongoTemplate() throws Exception {
logger.info("Creating MongoTemplate for Flipkart DB");
return new MongoTemplate(mongoDbFactory());
}
}
请注意，这些配置类中的每一个都在创建自己的 MongoTemplate 并启用自己的 MongoRepository。其中之一也必须是@Primary，否则弹簧靴会抛出错误。其中哪个是主要的并不重要。最终这些将连接到他们自己的存储库
4) 为每个数据库创建实体和存储库。
您现在需要为每个数据库创建一个存储库。鉴于所有数据库的集合都是相同的，我创建了以下示例实体 -
package com.akash.mongo.multidb.entity;
import java.io.Serializable;
import org.bson.types.ObjectId;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
import org.springframework.data.mongodb.core.mapping.Field;
/**
* Sample Entity class
* @author Akash
*
*/
@Document(collection="productDetails")
public class ProductDetails implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private ObjectId id;
@Field("productName")
private String productName;
@Field("productDesc")
private String productDesc;
@Field("productQuantity")
private String productQuantity;
public ObjectId getId() {
return id;
}
public void setId(ObjectId id) {
this.id = id;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public String getProductDesc() {
return productDesc;
}
public void setProductDesc(String productDesc) {
this.productDesc = productDesc;
}
public String getProductQuantity() {
return productQuantity;
}
public void setProductQuantity(String productQuantity) {
this.productQuantity = productQuantity;
}
}
您可以根据您的收藏详情创建/修改实体类。
亚马逊仓库
package com.akash.mongo.multidb.repository.amazon;
import org.bson.types.ObjectId;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;
import com.akash.mongo.multidb.entity.ProductDetails;
/**
*
* @author Akash
*
*/
@Repository
public interface AmazonRepository extends MongoRepository<ProductDetails, ObjectId> {
}
Flipkart 存储库
package com.akash.mongo.multidb.repository.flipkart;
import org.bson.types.ObjectId;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;
import com.akash.mongo.multidb.entity.ProductDetails;
@Repository
public interface FlipkartRepository extends MongoRepository<ProductDetails, ObjectId> {
}
易趣存储库
package com.akash.mongo.multidb.repository.ebay;
import org.bson.types.ObjectId;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;
import com.akash.mongo.multidb.entity.ProductDetails;
/**
*
* @author Akash
*
*/
@Repository
public interface EbayRepository extends MongoRepository<ProductDetails, ObjectId> {
}
同样，每个存储库都需要有自己的包，否则在运行应用程序时会出现错误。这是此解决方案的一个缺点，您必须创建与要连接的数据库一样多的存储库包。
5) 服务实现和连接到不同的存储库
ProductDetailsService接口
包 com.akash.mongo.multidb.service;
import com.akash.mongo.multidb.entity.ProductDetails;
/**
* Sample interface with one add method
* @author Akash
*
*/
public interface ProductDetailsService {
/**
*
* @param productOrigin - the shop name i.e. Amazon, Flipkart or ebay.
* @param productDetails - the product details to add
*/
public void addProductDetails(String productOrigin, ProductDetails productDetails) throws RuntimeException;
}
ProductDetailsServiceImpl 类 -
package com.akash.mongo.multidb.service;
import java.util.Map;
import org.bson.types.ObjectId;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.repository.MongoRepository;
import com.akash.mongo.multidb.entity.ProductDetails;
/**
* Implementation of ProductDetailsService interface
* @author Akash
*
*/
public class ProductDetailsServiceImpl implements ProductDetailsService {
private static final Logger logger = LoggerFactory.getLogger(ProductDetailsServiceImpl.class);
/*
* Spring boot will autowire all the repositories along with their name
* amazonRepository - amazon repository instance
* ebayRepository - ebay repository instance and so on
*/
@Autowired
Map<String, MongoRepository<ProductDetails, ObjectId>> repositories;
@Override
public void addProductDetails(String productOrigin, ProductDetails productDetails) throws RuntimeException {
logger.info("Adding product details into {} db", productOrigin);
//if productOrigin is Amazon; repositoryName will be amazonRepository which is already present in spring boot
String repositoryName = productOrigin.toLowerCase()+"Repository";
if(repositories.containsKey(repositoryName)) {
repositories.get(repositoryName).save(productDetails);
} else {
logger.error("{} shop is undefined in DB. Check and try again", productOrigin);
throw new RuntimeException("Shop doesnot exist in MongoDb");
}
}
}
ProductOrigin 您可以从您的请求或标头中获得任何可用的信息。
6) 最后，application.properties
更改每个数据库的数据库、用户名和密码详细信息。尽量不要使用管理员凭据；而是分别为每个数据库创建用户名和密码并更新 application.properties。
#MongoDb connection properties for Flipkart DB
flipkart.mongodb.database=flipkart
flipkart.mongodb.host=http://127.0.0.1
flipkart.mongodb.port=27017
flipkart.mongodb.username=flipkart
flipkart.mongodb.password=flipkart
#MongoDb connection properties for Amazon DB
amazon.mongodb.database=amazon
amazon.mongodb.host=http://127.0.0.1
amazon.mongodb.port=27017
amazon.mongodb.username=amazon
amazon.mongodb.password=amazon
#MongoDb connection properties for ebay DB
ebay.mongodb.database=ebay
ebay.mongodb.host=http://127.0.0.1
ebay.mongodb.port=27017
ebay.mongodb.username=ebay
ebay.mongodb.password=ebay
现在，如果您需要添加任何新数据库，您只需添加一个类似于 AmazonDbConfig 的配置类、一个包含该数据库所需存储库的包以及 application.properties 中的连接详细信息。在您的所有数据库的集合相同之前，无需更改服务。
如果您有多个集合，您可以为每个集合添加实体和存储库（将单个商店的所有存储库组合在一个包中）并且解决方案应该仍然有效。