Gradle项目构建失败

我正在尝试使用gradle工具构建RESTful WebService项目。但是构建失败了。控制台给出以下输出。

C:\Users\bob\Downloads\gs-rest-service-master\gs-rest-service-master\complete>gradle build
FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'complete'.
> Could not resolve all dependencies for configuration ':classpath'.
> Could not resolve org.springframework.boot:spring-boot-gradle-plugin:1.0.0.RC4.
Required by:
     :complete:unspecified
  > Could not GET 'http://repo.spring.io/libs-snapshot/org/springframework/boot/spring-   boot-gradle-plugin/1.0.0.RC4/spring-boot-gradle-plugin-1.0.0.RC4.pom'.
     > Connection to http://repo.spring.io refused
  > java.lang.NullPointerException (no error message)

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option   to get more log output.

当我发出命令时

gradle build --stacktrace

获取以下堆栈跟踪：

Caused by: org.gradle.api.internal.artifacts.ivyservice.ModuleVersionResolveException:               Could not resolve org.springframework.boot:spring-boot-gradle-plugin:1.0.0.RC4.
Required by:
:complete:unspecified
    at   org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver.r    esolve(RepositoryChainDependencyResolver.java:72)
    at   org.gradle.api.internal.artifacts.ivyservice.clientmodule.ClientModuleResolver.resolve(Clie    ntModuleResolver.java:35)
    at org.gradle.api.internal.artifacts.ivyservice.projectmodule.ProjectDependencyResolver.resolv      e(ProjectDependencyResolver.java:49)
    at   org.gradle.api.internal.artifacts.ivyservice.ivyresolve.LazyDependencyToModuleResolver$AbstractVersionResolveResult.resolve(LazyDependencyToModuleResolver.java:69)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DependencyGraphBuilder$ModuleVersionResolveState.resolve(DependencyGraphBuilder.java:655)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DependencyGraphBuilder$ModuleVersionResolveState.getMetaData(DependencyGraphBuilder.java:666)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DependencyGraphBuilder$DependencyEdge.calculateTargetConfigurations(DependencyGraphBuilder.java:340)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DependencyGraphBuilder$DependencyEdge.attachToTargetConfigurations(DependencyGraphBuilder.java:314)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DependencyGraphBuilder.traverseGraph(DependencyGraphBuilder.java:130)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DependencyGraphBuilder.resolve(DependencyGraphBuilder.java:70)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DefaultDependencyResolver$1.execute(DefaultDependencyResolver.java:116)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DefaultDependencyResolver$1.execute(DefaultDependencyResolver.java:82)
    at org.gradle.internal.Transformers$3.transform(Transformers.java:131)
    at org.gradle.api.internal.artifacts.ivyservice.DefaultIvyContextManager.withIvy(DefaultIvyContextManager.java:61)
    at org.gradle.api.internal.artifacts.ivyservice.DefaultIvyContextManager.withIvy(DefaultIvyContextManager.java:39)
    at org.gradle.api.internal.artifacts.ivyservice.resolveengine.DefaultDependencyResolver.resolve(DefaultDependencyResolver.java:82)
    at org.gradle.api.internal.artifacts.ivyservice.CacheLockingArtifactDependencyResolver$1.run(CacheLockingArtifactDependencyResolver.java:42)
    at org.gradle.internal.Factories$1.create(Factories.java:22)
    at org.gradle.cache.internal.DefaultCacheAccess.useCache(DefaultCacheAccess.java:187)
    at org.gradle.cache.internal.DefaultCacheAccess.useCache(DefaultCacheAccess.java:175)
    at org.gradle.cache.internal.DefaultPersistentDirectoryStore.useCache(DefaultPersistentDirectoryStore.java:106)
    at org.gradle.cache.internal.DefaultCacheFactory$ReferenceTrackingCache.useCache(DefaultCacheFactory.java:193)
    at org.gradle.api.internal.artifacts.ivyservice.DefaultCacheLockingManager.useCache(DefaultCacheLockingManager.java:65)
    at org.gradle.api.internal.artifacts.ivyservice.CacheLockingArtifactDependencyResolver.resolve(CacheLockingArtifactDependencyResolver.java:40)
    at org.gradle.api.internal.artifacts.ivyservice.SelfResolvingDependencyResolver.resolve(SelfResolvingDependencyResolver.java:45)
    at org.gradle.api.internal.artifacts.ivyservice.ShortcircuitEmptyConfigsArtifactDependencyResolver.resolve(ShortcircuitEmptyConfigsArtifactDependencyResolver.java:55)
    at org.gradle.api.internal.artifacts.ivyservice.ErrorHandlingArtifactDependencyResolver.resolve(ErrorHandlingArtifactDependencyResolver.java:47)
    at org.gradle.api.internal.artifacts.ivyservice.DefaultConfigurationResolver.resolve(DefaultConfigurationResolver.java:46)
    at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration.resolveNow(DefaultConfiguration.java:240)
    at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration.getResolvedConfiguration(DefaultConfiguration.java:230)
    at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration_Decorated.getResolvedConfiguration(Unknown Source)
    at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration$ConfigurationFileCollection.getFiles(DefaultConfiguration.java:463)
    ... 32 more
Caused by: org.gradle.api.internal.externalresource.transport.http.HttpRequestException: Could not GET 'http://repo.spring.io/libs-snapshot/org/springframework/boot/spring-boot-gradle-plugin/1.0.0.RC4/spring-boot-gradle-plugin-1.0.0.RC4.pom'.
    at org.gradle.api.internal.externalresource.transport.http.HttpClientHelper.performRequest(HttpClientHelper.java:80)
    at org.gradle.api.internal.externalresource.transport.http.HttpClientHelper.performRawGet(HttpClientHelper.java:66)
    at org.gradle.api.internal.externalresource.transport.http.HttpClientHelper.performGet(HttpClientHelper.java:70)
    at org.gradle.api.internal.externalresource.transport.http.HttpResourceAccessor.getResource(HttpResourceAccessor.java:46)
    at org.gradle.api.internal.externalresource.transport.http.HttpResourceAccessor.getResource(HttpResourceAccessor.java:32)
    at org.gradle.api.internal.externalresource.transfer.ProgressLoggingExternalResourceAccessor.getResource(ProgressLoggingExternalResourceAccessor.java:38)
    at org.gradle.api.internal.externalresource.transfer.DefaultCacheAwareExternalResourceAccessor.getResource(DefaultCacheAwareExternalResourceAccessor.java:60)
    at org.gradle.api.internal.externalresource.transport.DefaultExternalResourceRepository.getResource(DefaultExternalResourceRepository.java:65)
    at org.gradle.api.internal.artifacts.repositories.resolver.ExternalResourceResolver$ArtifactResolver.getResource(ExternalResourceResolver.java:579)
    at org.gradle.api.internal.artifacts.repositories.resolver.ExternalResourceResolver$ArtifactResolver.findStaticResourceUsingPatterns(ExternalResourceResolver.java:564)
    at org.gradle.api.internal.artifacts.repositories.resolver.ExternalResourceResolver$ArtifactResolver.resolveMetaDataArtifact(ExternalResourceResolver.java:548)
    at org.gradle.api.internal.artifacts.repositories.resolver.ExternalResourceResolver.findMetaDataArtifact(ExternalResourceResolver.java:191)
    at org.gradle.api.internal.artifacts.repositories.resolver.ExternalResourceResolver.resolveStaticDependency(ExternalResourceResolver.java:165)
    at org.gradle.api.internal.artifacts.repositories.resolver.MavenResolver.getDependency(MavenResolver.java:83)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CacheLockingModuleVersionRepository$2.run(CacheLockingModuleVersionRepository.java:54)
    at org.gradle.internal.Factories$1.create(Factories.java:22)
    at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:237)
    at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:308)
    at org.gradle.cache.internal.DefaultPersistentDirectoryStore.longRunningOperation(DefaultPersistentDirectoryStore.java:114)
    at org.gradle.cache.internal.DefaultCacheFactory$ReferenceTrackingCache.longRunningOperation(DefaultCacheFactory.java:185)
    at org.gradle.api.internal.artifacts.ivyservice.DefaultCacheLockingManager.longRunningOperation(DefaultCacheLockingManager.java:57)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CacheLockingModuleVersionRepository.getDependency(CacheLockingModuleVersionRepository.java:52)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CachingModuleVersionRepository.getDependency(CachingModuleVersionRepository.java:137)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.memcache.CachedRepository.getDependency(CachedRepository.java:74)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver$RepositoryResolveState$RemoteModuleAccess.getDependency(RepositoryChainDependencyResolver.java:216)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver$StaticVersionRepositoryResolveState.process(RepositoryChainDependencyResolver.java:228)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver$RepositoryResolveState.resolve(RepositoryChainDependencyResolver.java:182)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver.findLatestModule(RepositoryChainDependencyResolver.java:110)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver.findLatestModule(RepositoryChainDependencyResolver.java:86)
    at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.RepositoryChainDependencyResolver.resolve(RepositoryChainDependencyResolver.java:61)
    ... 63 more
   Caused by: org.apache.http.conn.HttpHostConnectException: Connection to http://repo.spring.io refused
    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:190)
    at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:294)
    at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:640)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:479)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
    at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:137)
    at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:118)
    at org.gradle.api.internal.externalresource.transport.http.HttpClientHelper.performHttpRequest(HttpClientHelper.java:111)
    at org.gradle.api.internal.externalresource.transport.http.HttpClientHelper.executeGetOrHead(HttpClientHelper.java:87)
    at org.gradle.api.internal.externalresource.transport.http.HttpClientHelper.performRequest(HttpClientHelper.java:78)
    ... 92 more
    Caused by: java.net.ConnectException: Connection timed out: connect
    at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:127)
    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180)
    ... 101 more

以下是我的Build.gradle文件的内容

buildscript {
    repositories {
        maven { url "http://repo.spring.io/libs-snapshot" }
        mavenLocal()
    }

    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.0.0.RC4")
    }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'

repositories {
    mavenCentral()
    maven { url "http://repo.spring.io/libs-snapshot" }
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web")
    compile("com.fasterxml.jackson.core:jackson-databind")
    testCompile("junit:junit")
}


jar {
    baseName = 'gs-rest-service'
    version =  '0.1.0'
}

task wrapper(type: Wrapper) {
    gradleVersion = '1.11'
}

请帮助我，为什么构建失败？这与代理设置有关吗？