在 digitalocean 上使用 spring-boot 和 gradle 运行 java 应用程序答案

【问题标题】：Running a java application with spring-boot, and gradle on digitalocean在 digitalocean 上使用 spring-boot 和 gradle 运行 java 应用程序
【发布时间】：2016-01-24 14:53:55
【问题描述】：

我正在尝试使用 eclipse、java、gradle、spring-boot 构建一个宁静的服务，并将其托管在数字海洋服务器上。当我在特定端口或其他地方访问数字海洋 url 时，我想获得 JSON 响应，因此我可以执行 123.456.78:90 并在浏览器中查看 JSON。

当我在 Eclipse 中运行它并访问 localhost 时，它工作正常。访问 localhost:port# 会得到所需的输出，但我注意到 eclipse 的控制台日志和我在服务器上运行它时的差异。

来自日食：

2016-01-24 09:42:56.245  INFO 7372 --- [           main] Keen.KeenAPICallTester                   : Starting KeenAPICallTester on ****-THINK with PID 7372 (C:\Users\****\workspace\****-ML\bin started by **** in C:\Users\****\workspace\****-ML)
2016-01-24 09:42:56.247  INFO 7372 --- [           main] Keen.KeenAPICallTester                   : No active profile set, falling back to default profiles: default
2016-01-24 09:42:56.299  INFO 7372 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@116af24: startup date [Sun Jan 24 09:42:56 EST 2016]; root of context hierarchy
2016-01-24 09:42:56.893  INFO 7372 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]
2016-01-24 09:42:57.492  INFO 7372 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 9011 (http)
2016-01-24 09:42:57.502  INFO 7372 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-01-24 09:42:57.503  INFO 7372 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.30
2016-01-24 09:42:57.599  INFO 7372 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-01-24 09:42:57.599  INFO 7372 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1301 ms
2016-01-24 09:42:57.880  INFO 7372 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2016-01-24 09:42:57.883  INFO 7372 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-01-24 09:42:57.884  INFO 7372 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-01-24 09:42:57.884  INFO 7372 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-01-24 09:42:57.885  INFO 7372 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2016-01-24 09:42:58.120  INFO 7372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@116af24: startup date [Sun Jan 24 09:42:56 EST 2016]; root of context hierarchy
2016-01-24 09:42:58.183  INFO 7372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/extractionTest],methods=[GET],produces=[application/json]}" onto public java.lang.Object Keen.MLJSONResponseController.testExtractionRequest()
2016-01-24 09:42:58.184  INFO 7372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/inspectAllProjectsTest],methods=[GET],produces=[application/json]}" onto public java.lang.Object Keen.MLJSONResponseController.testInspectionRequest()
2016-01-24 09:42:58.186  INFO 7372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2016-01-24 09:42:58.186  INFO 7372 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2016-01-24 09:42:58.208  INFO 7372 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-01-24 09:42:58.208  INFO 7372 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-01-24 09:42:58.246  INFO 7372 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-01-24 09:42:58.349  INFO 7372 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-01-24 09:42:58.402  INFO 7372 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 9011 (http)
2016-01-24 09:42:58.406  INFO 7372 --- [           main] Keen.KeenAPICallTester                   : Started KeenAPICallTester in 2.445 seconds (JVM running for 2.739)

来自数字海洋：

2016-01-24 09:22:11.190  INFO 29453 --- [           main] Keen.KeenAPICallTester                   : Starting KeenAPICallTester on **** with PID 29453 (/root/java-ml/learning/build/classes/main started by root in /root/java-ml/learning)
2016-01-24 09:22:11.224  INFO 29453 --- [           main] Keen.KeenAPICallTester                   : No active profile set, falling back to default profiles: default
2016-01-24 09:22:11.949  INFO 29453 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@8b87145: startup date [Sun Jan 24 09:22:11 EST 2016]; root of context hierarchy
2016-01-24 09:22:16.874  INFO 29453 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]
2016-01-24 09:22:20.350  INFO 29453 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 80 (http)
2016-01-24 09:22:20.448  INFO 29453 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-01-24 09:22:20.457  INFO 29453 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.30
2016-01-24 09:22:21.015  INFO 29453 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-01-24 09:22:21.016  INFO 29453 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 9086 ms
2016-01-24 09:22:22.582  INFO 29453 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]
2016-01-24 09:22:22.613  INFO 29453 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-01-24 09:22:22.636  INFO 29453 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-01-24 09:22:22.637  INFO 29453 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-01-24 09:22:22.637  INFO 29453 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]

我的猜测是，出于某种原因，我的数字海洋服务器不能很好地与 Tomcat 或其他东西配合使用。我通过ufw 命令打开了端口，检查了 iptables，安装了 apache2（我什至不知道我是否必须诚实）并确保在端口 8080 和 8000 中设置了接受出站和入站请求的配置。

我注意到我的请求方法没有被映射，这让我认为存在一些依赖问题。这是我的build.gradle 供参考。

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.3.1.RELEASE")

    }
}

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

mainClassName = "Keen.KeenAPICallTester"
applicationDefaultJvmArgs = ["--server.port=8000"]

jar {
    baseName = '****-ML'
    version =  '0.1.0'
}

repositories {
    mavenCentral()
}

sourceCompatibility = 1.8
targetCompatibility = 1.8



dependencies {
    compile("org.springframework.boot:spring-boot-starter-web")
    testCompile("junit:junit")
    compile fileTree(dir: 'libs', include: '*.jar')
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.3'
}

task(runSimple, dependsOn: 'classes', type: JavaExec) {
    main = 'Keen.KeenAPICallTester'
    classpath = sourceSets.main.runtimeClasspath
    args '--server.port=8000'
}

我的处理方式有问题吗？我还有一个runSimple 命令，这样我就可以运行 JVM 端口了，但这并没有什么区别，即使我将它设置为 80 并直接转到默认的数字海洋 IP 地址。

我之前在数字海洋上运行过应用程序，通常只需通过ufw 打开特定端口并在端口上运行应用程序，然后通过互联网访问它。但有些事情正在发生，我想了解。

【问题讨论】：

似乎应用程序被卡住了，因为它可能正在等待/dev/random（阻塞设备，可能已经干涸）。你可以使用/dev/urandom 来代替通过jvm-param -Djava.security.egd=file:/dev/./urandom 启动你的应用程序。见docs.oracle.com/cd/E13209_01/wlcp/wlss30/configwlss/…
哇，我试试看，但你怎么知道的？
这只是一个有根据的猜测。过去我遇到过类似的问题（网络应用程序在启动过程中卡住了）。我用strace和jstack调试了它。
成功了，非常感谢！
@fateddy 请将此添加为答案，因为它为我节省了很多时间！

标签： java eclipse spring gradle digital-ocean

【解决方案1】：

似乎应用程序被卡住了，因为它可能正在等待/dev/random（阻塞设备，可能已经干涸）。

您可以通过传递 JVM 参数 -Djava.security.egd=file:/dev/./urandom 来启动应用程序来代替使用 /dev/urandom。

见Avoiding JVM Delays Caused by Random Number Generation

此外，要深入研究这些奇怪的问题，jstack 或 strace 等工具可能会有所帮助。

【讨论】：