使用IntelliJ IDEA运行SpringBoot模块化项目失败

Question

我的项目是一个SpringBoot应用程序，包含一个Java模块。这个模块没有打开任何包。

module-info.java

module my.somewhere
{ 
    requires spring.core;
    requires spring.context;
    requires spring.boot;
    // and so on
}

当从命令行调用mvn clean spring-boot:run时，该应用程序按预期运行。

但是，当我尝试从SpringBootApplication的主方法启动它时，控制台会显示以下错误：java.lang.IllegalAccessException：模块my.somewhere未向模块spring.core开放my.somewhere.abc（请参见下面的详细堆栈）。

由于Spring的反射操作，将某些内容打开给Spring看起来是合理的，但我想知道为什么Maven可以毫无问题地运行它。

请帮助我理解如何使应用程序类似地从Maven 3.6.1和IntelliJ IDEA 2019.3运行。

---

详细堆栈：

org.springframework.cglib.core.CodeGenerationException: java.lang.IllegalAccessException-->module my.somewhere does not open my.somewhere.abc to module spring.core
    at [e-mail]/org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:514) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:363) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:582) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:110) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:108) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54) ~[spring-core-5.2.4.RELEASE.jar:na]
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
    at [e-mail]/org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:134) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:319) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:569) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:416) ~[spring-core-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.annotation.ConfigurationClassEnhancer.createClass(ConfigurationClassEnhancer.java:137) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.annotation.ConfigurationClassEnhancer.enhance(ConfigurationClassEnhancer.java:109) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.annotation.ConfigurationClassPostProcessor.enhanceConfigurationClasses(ConfigurationClassPostProcessor.java:423) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanFactory(ConfigurationClassPostProcessor.java:257) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:286) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:130) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:706) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532) ~[spring-context-5.2.4.RELEASE.jar:na]
    at [e-mail]/org.springframework.boot.web.reactive.context.ReactiveWebServerApplicationContext.refresh(ReactiveWebServerApplicationContext.java:66) ~[spring-boot-2.2.5.RELEASE.jar:na]
    at [e-mail]/org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.5.RELEASE.jar:na]
    at [e-mail]/org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.5.RELEASE.jar:na]
    at [e-mail]/org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.5.RELEASE.jar:na]
    at [e-mail]/org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.5.RELEASE.jar:na]
    at [e-mail]/org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.5.RELEASE.jar:na]
    at my.somewhere@0.0.2/my.somewhere.MyApplication.main(MyApplication.java:11) ~[classes/:na]
Caused by: java.lang.IllegalAccessException: module my.somewhere does not open my.somewhere.abc to module spring.core
    at java.base/java.lang.invoke.MethodHandles.privateLookupIn(MethodHandles.java:202) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
    at [e-mail]/org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:508) ~[spring-core-5.2.4.RELEASE.jar:na]
    ... 27 common frames omitted

- diziaq

---

尝试在Java命令行参数中使用--add-opens。 - Andrey

Answer 1

在模块声明前加上open，这样就可以解决问题了：

open module my.somewhere
{ 
    requires spring.core;
    requires spring.context;
    requires spring.boot;
    // and so on
}

- runekid

Answer 2

因为如果你使用mvn clean spring-boot:run运行它，所有的类和JAR文件都在类路径而不是模块路径中。

所以当使用Maven插件或可执行的JAR运行时，没有模块系统。

- Simon Martinelli

---

也许你可以提供一些提示或链接来帮助解决这个问题。 - diziaq

问题是为什么你想要使用Java模块系统。没有人会在Spring Boot中使用它。 - Simon Martinelli