求助：Flutter应用执行flutter pub get后在VS Code中运行报错java.rmi.ConnectException: Connection refused to host: 127.0.0.1

Hey there, let's tackle this java.rmi.ConnectException you're hitting after running flutter pub get. This error usually pops up when the Gradle daemon can't establish a connection to its RMI server, which often ties to local network/port issues or Gradle cache corruption after updating dependencies.

Common Fixes to Try #

1. Kill and Restart Stale Java/Gradle Processes #

Gradle might be stuck with a stale daemon process holding onto a port. Run these commands in your terminal to clear them out:

# Windows users
taskkill /F /IM java.exe
# macOS/Linux users
pkill -f java

After this, close and reopen VS Code, then try running your app again.

2. Disable Gradle Daemon (Temporary Workaround) #

You can bypass the RMI issue by forcing Gradle to run in non-daemon mode. Head to your project's android folder, create or edit the gradle.properties file, and add this line:

org.gradle.daemon=false

Save the file, then run these commands in your project root:

flutter clean
flutter pub get

Now try launching your app again.

3. Check Firewall/Antivirus Blocking #

Sometimes firewalls or antivirus tools block the dynamic ports that Gradle's RMI server uses. Temporarily disable your firewall/antivirus and test if the error goes away. If it does, add exceptions for:

• java.exe (your JDK's Java executable)
• adb.exe (Android Debug Bridge)
• Your Flutter project's root folder

4. Reset Flutter and Gradle Caches #

Corrupted cache files are a common culprit. Run these commands in sequence:

# Clean Flutter project cache
flutter clean
# Repair pub cache
flutter pub cache repair
# Move to Android folder and clean Gradle
cd android
./gradlew clean
./gradlew build --refresh-dependencies
# Go back to project root
cd ..
# Reinstall dependencies
flutter pub get

5. Verify Java Environment Setup #

Make sure your JAVA_HOME environment variable points to a valid JDK installation (preferably the one bundled with Android Studio). Check it with:

# Windows
echo %JAVA_HOME%
# macOS/Linux
echo $JAVA_HOME

If it's incorrect, update JAVA_HOME to point to Android Studio's bundled JBR (e.g., C:\Program Files\Android\Android Studio\jbr on Windows, /Applications/Android Studio.app/Contents/jbr on macOS).

Quick Note on Your App Code #

While it's not related to the current RMI error, there's a syntax issue in your _HomeState class that will cause runtime crashes once you fix the connection problem:

• Duplicate @override annotations
• dispose() method incorrectly nested inside initState()

Here's the corrected version of that section:

class _HomeState extends State<Home> {
  VideoPlayerController _controller;

  @override
  void initState() {
    super.initState();
    // Pointing the video controller to our local asset.
    _controller = VideoPlayerController.asset("assets/02.mp4")
      ..initialize().then((_) {
        // Once the video has been loaded we play the video and set looping to true.
        _controller.play();
        _controller.setLooping(true);
        // Ensure the first frame is shown after the video is initialized.
        setState(() {});
      });
  }

  @override
  void dispose() {
    super.dispose();
    _controller.dispose();
  }

  // Rest of your build method...
}

内容的提问来源于stack exchange，提问作者sara97