我正在尝试使用MongoDB和JPA部署一个简单的应用程序，但是我无法使它正常工作。
当我在Docker容器中部署应用程序时，我不断收到以下错误：

2020-10-05 18:47:39.770 INFO 1 --- [localhost:27017] org.mongodb.driver.cluster : Exception in monitor thread while connecting to server localhost:27017

com.mongodb.MongoSocketOpenException: Exception opening socket
    at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:70) ~[mongodb-driver-core-4.0.5.jar!/:na]
    at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:127) ~[mongodb-driver-core-4.0.5.jar!/:na]
    at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:117) ~[mongodb-driver-core-4.0.5.jar!/:na]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_212]
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:1.8.0_212]
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_212]
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_212]
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_212]
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_212]
    at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_212]
    at com.mongodb.internal.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:63) ~[mongodb-driver-core-4.0.5.jar!/:na]
    at com.mongodb.internal.connection.SocketStream.initializeSocket(SocketStream.java:79) ~[mongodb-driver-core-4.0.5.jar!/:na]
    at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:65) ~[mongodb-driver-core-4.0.5.jar!/:na]
    ... 3 common frames omitted

这是我用来构建映像的dockerfile：

FROM openjdk:8-jdk-alpine
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

还有我用来运行mongoDB的docker-compose.yml：

# Use root/example as user/password credentials

version: '3.1'

services:

  mongo:
    image: mongo
    restart: always
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: example

  mongo-express:
    image: mongo-express
    restart: always
    ports:
      - 8081:8081
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: example

我的实体都遵循以下模式（实体的名称）：

@Document
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class <Name>Entity {
    @Id
    private Integer <Name>Id;
    // More data
}

以及我的JPA仓库（如上所述，是jpa类和实体的名称）：

public interface <Name>JPA extends MongoRepository<<Name>Entity, Integer>{
}

最后，我在www.example.com下定义了以下属性application.properties:

spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.database=api-database
spring.data.mongodb.username=root
spring.data.mongodb.password=example
spring.data.mongodb.repositories.enabled=true

我可以连接到localhost：8081来查看mongo-express接口，但除此之外，我什么也看不到。