如何解决“无法连接到服务器 (32103) - java.net.ConnectException: 连接被拒绝”在码头工人？

Question

我有一个 Java Maven 应用程序，当在本地运行时，该应用程序成功连接到在 Docker 中运行的 MQTT 代理。问题是，当同一个Java应用程序在docker的容器中运行时，无法连接。这以前有用过。

这是我得到的异常：

Failed to connect to the MQTT broker with address ws://localhost:9001 Unable to connect to server (32103) - java.net.ConnectException: Connection refused

这是 Java 应用程序的 Dockerfile：

#Required
FROM eclipse-temurin:16

# The jar file that will be run. This is a result of the build process
ARG JAR_FILE=target/*.jar

# The dependencies folder for all maven dependencies
ARG DEPENDENCIES=target/dependency/

# Make a directory for the jar
RUN mkdir /src

# Make a directory for the dependencies
RUN mkdir /src/lib

#Make a directoryfor the ServerConfig file 
RUN mkdir -p /src/main/resources
#Echo Jar File
RUN echo $JAR_FILE

# Copy the jar from it's original location to the docker container
COPY acs-simulator/${JAR_FILE} /src/jar/
#Echo Jar File
RUN echo $(ls -1 /src/jar/)


RUN echo pwd

# Copy all of the dependencies of the jar to the docker container
COPY acs-simulator/${DEPENDENCIES} /src/lib

# The entry point is the command the docker container will run when it start, so in this case it will start the jar
ENTRYPOINT ["java","-jar","/src/jar/acs-simulator-latest.jar"]

这也是 MQTT 代理配置：

## Logging

log_dest stdout
log_type error
log_type warning
log_type notice
log_type information

## MQTT Listener

listener 1883
protocol mqtt

## WebSockets Listener

listener 9001
protocol websockets

## Persistence

persistence false

这是我打印异常的方法：

  @Override
    public void onMQTTConnectionFailure(IMqttToken iMqttToken,Throwable throwable) {
        this.logger.log("Failed to connect to the MQTT broker with address " + this.client.getBrokerAddress() + " " + throwable + "   " + iMqttToken ,
                ILogger.LogLevel.ERROR);

        waitAndReconnectToBroker();
    }