引入spring-data 依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>

数据源配置，多个数据源

spring:
    mongodb:

      primary:
        uri: mongodb://username1:password1@localost:27018/db1

      secondary:
        uri: mongodb://username2:password2@localost:27018/db2

　　　 thirdly: 
　　　　 uri:mongodb://username3:password3@localost:27018/db3

配置类

@Data
public abstract class AbstractMongoConfig {

    private String uri;

    public abstract MongoTemplate mongoTemplate();

    public MongoDbFactory mongoDbFactory(){
        MongoClientURI mongoclienturi = new MongoClientURI(uri);
        return new SimpleMongoDbFactory(mongoclienturi);
    }

}

@Configuration
@ConfigurationProperties(prefix = "spring.data.mongodb.primary")
public class PrimaryMongoConfig extends AbstractMongoConfig  {

    @Primary   //默认会注入此数据源的Template
    @Override
    @Bean(name = "primaryMongoTemplate")
    public MongoTemplate mongoTemplate(){
        return new MongoTemplate(mongoDbFactory());
    }
}

@Configuration
@ConfigurationProperties(prefix = "spring.data.mongodb.secondary")
public class SecondaryMongoConfig extends  AbstractMongoConfig{

    @Override
    @Bean(name = "secondaryMongoTemplate")
    public MongoTemplate mongoTemplate(){
        return new MongoTemplate(mongoDbFactory());
    }
}

@Configuration
@ConfigurationProperties(prefix = "spring.data.mongodb.thirdly")
public class ThirdlyMongoConfig extends  AbstractMongoConfig{

    @Override
    @Bean(name = "thirdlyMongoTemplate")
    public MongoTemplate mongoTemplate(){
        return new MongoTemplate(mongoDbFactory());
    }
}

使用MongoTemplate 进行增删改查

　　@Autowired
    private MongoTemplate mongoTemplate;

　　 @Autowired
    @Qualifier("secondaryMongoTemplate")
    private MongoTemplate template2;

    @Autowired
    @Qualifier("thirdlyMongoTemplate")
    private MongoTemplate template3;