netbeans java模块层:ModuleLayer.Controller添加方法不起作用

dfddblmv  于 2022-11-10  发布在  Java
关注(0)|答案(1)|浏览(132)

我使用的是Netbeans 12.5和java 16
在Java模块化项目中,我有2个模块

Modular-Testing(/*The Project Name*/)
|
|----Consumer(/*Module Name*/)
|    |
     |--classes(/*Folder Name*/)
        |
        |--main(/*package name*/)
           |
           |--CustomModuleTest.java(Main Class)    

|--Test_Module_A(/*Module Name*/)
    |
    |--classes(/*Folder Name*/)
        |
        |--package_a(/*package name*/)
           |
           |--ClassA.java

CustomModuleTest.java

public static void main(String[] args)throws Exception
{
   Path baseDir=Path.of("C:/Users/Home/Documents/NetBeansProjects/Netbeans/Modular-Testing/build/modules/");

   //Create the configuration for these two modules with boot-layer configuration as it's parent
   Configuration level1=Configuration.resolve
   (
     ModuleFinder.of(baseDir.resolve("Consumer"),baseDir.resolve("Test_Module_A"))
    ,List.of(ModuleLayer.boot().configuration())
    ,ModuleFinder.of()
    ,List.of("Consumer","Test_Module_A")
   );   

   //create the module layer with only one system class loader and boot layer as parent
   ModuleLayer.Controller layer1=ModuleLayer.defineModulesWithOneLoader
   (
     level1
    ,List.of(ModuleLayer.boot())
    ,ClassLoader.getSystemClassLoader()
   ); 

   //this is the main purpose of this test. I want to call ClassA.callMe() via reflection after I have dynamically achieved the permissions for it by first
   //Making Consumer Module read(requires) Test_Module_A
   //Making Test_Module_A open it's package(package_a) to Consumer
   //With this consumer should have full reflective access to Test_Module_A(or that's what i had hoped but it didn't work)

                          //Require(Read)
   //Make Module Consumer--------------->Test_Module_A 
   layer1.addReads
   (
     layer1.layer().findModule("Consumer").get()
    ,layer1.layer().findModule("Test_Module_A").get()
   ); 
                                 //Open package_a
   //Make Module Test_Module_A-------------------->Consumer 
   layer1.addOpens
   (
    layer1.layer().findModule("Test_Module_A").get()
   ,"package_a"
   ,layer1.layer().findModule("Consumer").get()
   ); 

   //Do the actual Test
   Class targetClass=layer1.layer().findLoader("Test_Module_A").loadClass("package_a.ClassA");
   Method method=targetClass.getDeclaredMethod("callMe");
   method.trySetAccessible();
   method.invoke(null);  //<---------Crashes Here(It's a static method so no object reference)
}

A类不执行任何操作

package package_a;

public class ClassA 
{
  private static void callMe()
  {
   System.out.println("Hooray You Called Me Using ModuleLayers!!!");
  }
}

使用者& Test_Module_A的模块信息均为空

module Consumer{}
module Test_Module_A{}

这两个模块的module-info都是空的,因为我想使用ModuleLayer.Controller动态添加打开/导出
找到类时没有问题,使用trySetAccessible()使方法可访问,但只要我调用invoke,就会出现此错误

Exception in thread "main" java.lang.IllegalAccessException: class main.CustomModuleTest (in module Consumer) cannot access class package_a.ClassA (in module Test_Module_A) because module Test_Module_A does not export package_a to module Consumer
    at java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Reflection.java:385)
    at java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:687)
    at java.base/java.lang.reflect.Method.invoke(Method.java:559)

测试从CustomModuleTest.java消费者模块内的www.example.com main方法运行,addReads和addOpens方法要么不起作用,要么我只是使用错误
有什么想法吗?

zfycwa2u

zfycwa2u1#

您正在创建一个包含两个模块的新模块层,并建立其中一个模块对另一个模块的访问。但是,您实际上希望为当前运行的main方法建立对其中一个模块的访问。
当前运行的main方法不能是它刚刚创建的新模块层的一部分。假设是标准的启动器设置,它属于Controller模块,该模块由系统类加载器作为引导层的一部分加载。
因此,您必须更改代码以授予对已经加载的Controller模块的访问权限,而不是授予对新层中同名新模块的访问权限。由于新模块层的新Controller模块没有任何作用,因此您可以将其从层配置中删除。

public static void main(String[] args) throws Exception {
   Path baseDir = Path.of(
     "C:/Users/Home/Documents/NetBeansProjects/Netbeans/Modular-Testing/build/modules/");

   // Create the configuration for the new module
   // with boot-layer configuration as it's parent
   Configuration level1=Configuration.resolve
   (
     ModuleFinder.of(baseDir.resolve("Test_Module_A")),
     List.of(ModuleLayer.boot().configuration()),
     ModuleFinder.of(), List.of("Test_Module_A")
   );

   //create the module layer with only one class loader and boot layer as parent
   var layer1Controller = ModuleLayer.defineModulesWithOneLoader(
     level1, List.of(ModuleLayer.boot()), ClassLoader.getSystemClassLoader()
   );
   var testModA = layer1Controller.layer().findModule("Test_Module_A").get();
   var myModule = CustomModuleTest.class.getModule();

   myModule.addReads(testModA); // add read edge

   layer1Controller.addOpens(testModA, "package_a", myModule); // open package_a

   //Do the actual Test
   Class<?> targetClass = testModA.getClassLoader().loadClass("package_a.ClassA");
   Method method = targetClass.getDeclaredMethod("callMe");
   method.setAccessible(true);
   method.invoke(null);
}

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