无法构建gradle并创建java类

我的android工作室中的任何项目都无法构建。错误信息如下 –

Gradle sync failed: Could not run build action using Gradle distribution 'https://services.gradle.org/distributions/gradle-3.3-all.zip'. Consult IDE log for more details (Help | Show Log) 

此外，我无法通过File-> new-> Java类在android studio中创建一个新的java类，因为没有这样的选项可用。 我找到了一些答案说右键单击java文件夹，然后单击标记目录为 – > SOURce root，即使此选项也不存在。 此外，为了解决gradle问题，我发现一些答案说单击文件 – >无效缓存/重新启动并删除主目录中的.gradle文件然后更新android studio，我做了相应但仍然无效。 build.gradle内容是 –

 apply plugin: 'com.android.application' android { compileSdkVersion 25 buildToolsVersion "25.0.2" defaultConfig { applicationId "com.example.android.iitmandi" minSdkVersion 15 targetSdkVersion 25 versionCode 1 versionName "1.0" testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:25.2.0' compile 'com.android.support.constraint:constraint-layout:1.0.0-beta5' testCompile 'junit:junit:4.12' } 

gradle-wrapper.properties的内容是 –

 #Tue Mar 28 20:10:53 IST 2017 distributionBase=GRADLE_USER_HOME distributionPath=wrapper/dists zipStoreBase=GRADLE_USER_HOME zipStorePath=wrapper/dists distributionUrl=https\://services.gradle.org/distributions/gradle-3.3-all.zip 

Build.grale-

 // Top-level build file where you can add configuration options common to all sub-projects/modules. buildscript { repositories { jcenter() } dependencies { classpath 'com.android.tools.build:gradle:2.3.0' // NOTE: Do not place your application dependencies here; they belong // in the individual module build.gradle files } } allprojects { repositories { jcenter() } } task clean(type: Delete) { delete rootProject.buildDir } 

在做Build-> Clean项目这个错误信息显示 –

 Error:A problem occurred configuring project ':app'. > Could not resolve all dependencies for configuration ':app:_debugUnitTestApkCopy'. > Could not resolve junit:junit:4.12. Required by: project :app > Could not resolve junit:junit:4.12. > Could not get resource 'https://jcenter.bintray.com/junit/junit/4.12/junit-4.12.pom'. > Could not GET 'https://jcenter.bintray.com/junit/junit/4.12/junit-4.12.pom'. > Connect to jcenter.bintray.com:443 [jcenter.bintray.com/108.168.243.150] failed: Connection timed out 

我甚至卸载了Android-Studio 2.3并安装了2.2.2，但问题仍然存在