错误：卡在Download maven-metadata.xml...很久

一、问题描述：

同步时候卡在Download maven-metadata.xml...，半个小时后提示以下错误：

Starting Gradle Daemon...
Gradle Daemon started in 5 s 892 ms
IOException: https://dl.google.com/android/repository/addons_list-3.xml
java.net.ConnectException: Connection refused: connect
IOException: https://dl.google.com/android/repository/addons_list-2.xml
java.net.ConnectException: Connection refused: connect
IOException: https://dl.google.com/android/repository/addons_list-1.xml
java.net.ConnectException: Connection refused: connect
Failed to download any source lists!
IO exception while downloading manifest:
java.net.ConnectException: Connection refused: connect
        at java.base/java.net.PlainSocketImpl.connect0(Native Method)
        at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:101)
        at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
        at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
        at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
        at java.base/java.net.Socket.connect(Socket.java:609)
        at java.base/java.net.Socket.connect(Socket.java:558)
        at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:182)
        at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:474)
        at java.base/sun.net.www.http.HttpClient$1.run(HttpClient.java:526)
        at java.base/sun.net.www.http.HttpClient$1.run(HttpClient.java:524)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at java.base/sun.net.www.http.HttpClient.privilegedOpenServer(HttpClient.java:523)
        at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:564)
        at java.base/sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:265)
        at java.base/sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:372)
        at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:191)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1232)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1081)
        at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:177)
        at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:168)
        at com.android.sdklib.repository.legacy.remote.internal.DownloadCache.openUrl(DownloadCache.java:247)
        at com.android.sdklib.repository.legacy.remote.internal.DownloadCache.downloadAndCache(DownloadCache.java:624)
        at com.android.sdklib.repository.legacy.remote.internal.DownloadCache.openCachedUrl(DownloadCache.java:455)
        at com.android.sdklib.repository.legacy.LegacyDownloader.downloadAndStream(LegacyDownloader.java:61)
        at com.android.repository.impl.downloader.LocalFileAwareDownloader.downloadAndStream(LocalFileAwareDownloader.java:51)
        at com.android.repository.impl.manager.RemoteRepoLoaderImpl.lambda$fetchPackages$0(RemoteRepoLoaderImpl.java:139)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)

Still waiting for package manifests to be fetched remotely.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.7.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 29m 13s

二、解决办法：

找到电脑 C:\Users\Lenovo\.gradle\gradle.properties （不同电脑目录不同）文件并打开，把一些代理配置的东西注释掉即可。大概以下这些东西

#systemProp.http.proxyHost=x.x.x.x

#systemProp.http.proxyPort=xxxx

#systemProp.https.proxyHost=x.x.x.x

#systemProp.https.proxyPort=xxxx

#org.gradle.jvmargs=-DsocksProxyHost=x.x.x.x -DsocksProxyPort=xxxx