错误：package com.google.common.base 不存在

给定java中的以下代码，在编译它时，你有很多错误：

Main.java：1： error： package com.google.common.base 不存在 import com.google.common.base.Preconditions;^

Main.java：2： error： package com.google.common.collect 不存在 import com.google.common.collect.Lists;^

Main.java：3： error： package org.ros.exception 不存在 import org.ros.exception.RosRuntimeException;^

Main.java：4： error： package org.ros.internal.loader 不存在 import org.ros.internal.loader.CommandLineLoader;^

Main.java：5： error： package org.ros.node 不存在 import org.ros.node.DefaultNodeMainExecutor;^

Main.java：6： error： package org.ros.node 不存在 import org.ros.node.NodeConfiguration;^

Main.java：7： error： package org.ros.node 不存在 import org.ros.node.NodeMainExecutor;

我通过IntelliJ运行它。有谁知道为什么它不起作用？

import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import org.ros.exception.RosRuntimeException;
import org.ros.internal.loader.CommandLineLoader;
import org.ros.node.DefaultNodeMainExecutor;
import org.ros.node.NodeConfiguration;
import org.ros.node.NodeMainExecutor;

// This class will run a publisher and subscriber, and relay data between them.

public class Main {

static private Talker pubNodeMain;

static private Listener subNodeMain;

public static void main(String[] argv) throws Exception {
    // Set up the executor for both of the nodes
    NodeMainExecutor nodeMainExecutor = DefaultNodeMainExecutor.newDefault();

    // Load the publisher
    String[] pubArgv = {"Talker"};
    CommandLineLoader pubLoader = new CommandLineLoader(Lists.newArrayList(pubArgv));
    String nodeClassName = pubLoader.getNodeClassName();
    System.out.println("Loading node class: " + pubLoader.getNodeClassName());
    NodeConfiguration pubNodeConfiguration = pubLoader.build();

    try {
        pubNodeMain = (Talker) pubLoader.loadClass(nodeClassName);
    } catch (ClassNotFoundException e) {
        throw new RosRuntimeException("Unable to locate node: " + nodeClassName, e);
    } catch (InstantiationException e) {
        throw new RosRuntimeException("Unable to instantiate node: " + nodeClassName, e);
    } catch (IllegalAccessException e) {
        throw new RosRuntimeException("Unable to instantiate node: " + nodeClassName, e);
    }

    Preconditions.checkState(pubNodeMain != null);
    nodeMainExecutor.execute(pubNodeMain, pubNodeConfiguration);

    // Load the subscriber
    String[] subArgv = {"Listener"};
    CommandLineLoader subLoader = new CommandLineLoader(Lists.newArrayList(subArgv));
    nodeClassName = subLoader.getNodeClassName();
    System.out.println("Loading node class: " + subLoader.getNodeClassName());
    NodeConfiguration subNodeConfiguration = subLoader.build();

    try {
        subNodeMain = (Listener) subLoader.loadClass(nodeClassName);
    } catch (ClassNotFoundException e) {
        throw new RosRuntimeException("Unable to locate node: " + nodeClassName, e);
    } catch (InstantiationException e) {
        throw new RosRuntimeException("Unable to instantiate node: " + nodeClassName, e);
    } catch (IllegalAccessException e) {
        throw new RosRuntimeException("Unable to instantiate node: " + nodeClassName, e);
    }

    Preconditions.checkState(subNodeMain != null);
    nodeMainExecutor.execute(subNodeMain, subNodeConfiguration);
  }

}