问题：Flutter create新建项目之后运行，一直报错显示Exception in thread "main" java.net.ConnectException: Connection timed out: connect
Exception in thread "main" java.net.ConnectException: Connection timed out: connect
at java.base/sun.nio.ch.Net.connect0(Native Method)
at java.base/sun.nio.ch.Net.connect(Unknown Source)
at java.base/sun.nio.ch.Net.connect(Unknown Source)
at java.base/sun.nio.ch.NioSocketImpl.connect(Unknown Source)
at java.base/java.net.SocksSocketImpl.connect(Unknown Source)
at java.base/java.net.Socket.connect(Unknown Source)
at java.base/sun.security.ssl.SSLSocketImpl.connect(Unknown Source)
at java.base/sun.security.ssl.BaseSSLSocketImpl.connect(Unknown Source)
at java.base/sun.net.NetworkClient.doConnect(Unknown Source)
at java.base/sun.net.www.http.HttpClient.openServer(Unknown Source)
at java.base/sun.net.www.http.HttpClient.openServer(Unknown Source)
at java.base/sun.net.www.protocol.https.HttpsClient.<init>(Unknown Source)
at java.base/sun.net.www.protocol.https.HttpsClient.New(Unknown Source)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.followRedirect0(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.followRedirect(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source)
at org.gradle.wrapper.Download.downloadInternal(Download.java:58)
at org.gradle.wrapper.Download.download(Download.java:44)
at org.gradle.wrapper.Install$1.call(Install.java:61)
at org.gradle.wrapper.Install$1.call(Install.java:48)
at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
at org.gradle.wrapper.Install.createDist(Install.java:48)
at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
Running Gradle task 'assembleDebug'... 23.0s
[!] Gradle threw an error while downloading artifacts from the network.
Retrying Gradle Build: #1, wait time: 100ms
Exception in thread "main" java.net.ConnectException: Connection timed out: connect
at java.base/sun.nio.ch.Net.connect0(Native Method)
at java.base/sun.nio.ch.Net.connect(Unknown Source)
at java.base/sun.nio.ch.Net.connect(Unknown Source)
at java.base/sun.nio.ch.NioSocketImpl.connect(Unknown Source)
at java.base/java.net.SocksSocketImpl.connect(Unknown Source)
at java.base/java.net.Socket.connect(Unknown Source)
at java.base/sun.security.ssl.SSLSocketImpl.connect(Unknown Source)
at java.base/sun.security.ssl.BaseSSLSocketImpl.connect(Unknown Source)
at java.base/sun.net.NetworkClient.doConnect(Unknown Source)
at java.base/sun.net.www.http.HttpClient.openServer(Unknown Source)
at java.base/sun.net.www.http.HttpClient.openServer(Unknown Source)
at java.base/sun.net.www.protocol.https.HttpsClient.<init>(Unknown Source)
at java.base/sun.net.www.protocol.https.HttpsClient.New(Unknown Source)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.followRedirect0(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.followRedirect(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source)
at org.gradle.wrapper.Download.downloadInternal(Download.java:58)
at org.gradle.wrapper.Download.download(Download.java:44)
at org.gradle.wrapper.Install$1.call(Install.java:61)
at org.gradle.wrapper.Install$1.call(Install.java:48)
at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
at org.gradle.wrapper.Install.createDist(Install.java:48)
at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
Running Gradle task 'assembleDebug'... 22.8s
[!] Gradle threw an error while downloading artifacts from the network.
Error: Gradle task assembleDebug failed with exit code 1
其实主要估计就是网络超时问题，我上网搜了一波发现都建议
需要修改项目下 android/build.gradle 和 flutter 安装目录flutter/packages/flutter_tools/gradle/flutter.gradle 两个文件中 buildscript 和allprojects 中的
google()
jcenter()
替换成阿里云镜像
maven { url 'https://maven.aliyun.com/repository/google' }
maven { url 'https://maven.aliyun.com/repository/jcenter' }
maven { url'http://maven.aliyun.com/nexus/content/groups/public' }
但是我替换后还是回显示同样的错误，开始思考其实之所以这样修改，是因为更快下载到需要的gradle.zip文件,所以我就直接在services.gradle.org/distributio…
步骤一：到你项目里面的gradle-wrapper.properties文件里面查找到你所需要的版本，我这里是gradle-6.7-all.zip
步骤二：到这里services.gradle.org/distributio…
步骤三：找到你的.grade地方，我电脑所在是 C:\Users\husk.gradle ，然后将刚刚下载成功的zip包放在该目录下（其实你喜欢放在哪都无所谓，反正到时候引入本地这个zip就好）
步骤四：到你项目里面的gradle-wrapper.properties文件里面将原来的 distributionUrl=services.gradle.org/distributio… 换乘本地的
然后运行，运行成功了！！！
