我有什么方法可以覆盖 Java 中的系统属性吗？

发布于 2024-07-20 16:58:12 字数 999 浏览 3 评论 0原文

我遇到一个实际问题，该问题可以描述如下。

我们正在开发一个组件（例如插件），用于在外部 CMS 内使用外部 CMS 提供的 API 触发事件时执行某些任务。他们提供了一些jar库，所以我们要做的就是实现他们提供的接口。然后当事件被触发时调用内部方法。（当第一个事件触发时，CMS 仅创建一个类实例，然后它只执行每个事件触发的方法）

该功能可以总结如下，

import com.external.ProvidedInterface;


public class MonitorProgram implements ProvidedInterface{

   public void process(){
      //This method is called when an event is triggered in CMS
   }

}

在我们的类中，我们使用“javax.net.ssl.HttpsURLConnection” （Java 1.5）。但是 HttpsURLConnection 在 1.4 版本中从 com.sun.net.ssl 迁移到了 javax.net.ssl。但我提到的 CMS（我们实际上并不知道他们的实现）似乎使用了类似的东西，

System.setProperty("java.protocol.handler.pkgs","com.sun.net.ssl.internal.www.protocol");

导致我们的代码中出现 ClassCastException。

我想我的问题很清楚。在我们的例子中，我们无法设置VM参数，

-Djava.protocol.handler.pkgs=

也无法使用它来设置它，

System.setProperty("")

因为CMS和我们的程序的VM实例是相同的。

我该怎么做才能解决这个问题？还有想法或经验？

原文

I am getting a practical issue and the issue can be dascribed as follows.

We are developing a component (Say a plugin) to do some task when an event is triggered within an external CMS using the API provided by them. They have provided some jar libraries, So what we are doing is implementing an Interface provided by them. Then an internal method is called when an event is triggered. (The CMS is creating only one instance of class when the first event triggers, then it just executes the method with each event trigger)

The function can be summarized as follows,

import com.external.ProvidedInterface;


public class MonitorProgram implements ProvidedInterface{

   public void process(){
      //This method is called when an event is triggered in CMS
   }

}

Within our class we are using "javax.net.ssl.HttpsURLConnection" (JAVA 1.5). But HttpsURLConnection migrated to javax.net.ssl from com.sun.net.ssl for 1.4. But it seems the CMS I am referring to (We dont know their implementation actually) uses something like this

System.setProperty("java.protocol.handler.pkgs","com.sun.net.ssl.internal.www.protocol");

leading to a ClassCastException in our code.

I think my question is clear. In our case we cant set VM parameters,

-Djava.protocol.handler.pkgs=

Also we cant set it back using,

System.setProperty("")

because the VM instance is same for CMS and our program.

What can I do for get this problem resolved? And idea or experiences?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

a√萤火虫的光℡ 2024-07-27 16:58:12

这对我来说并不清楚。

您想覆盖系统属性吗？
你可以这样做。

在调用外部库方法之前覆盖 System.property，当该方法返回时，您可以设置旧的 System.property

    final String propertyName = "Property";
    String oldProperty = System.getProperty(propertyName);
    System.setProperty(propertyName,"NEW_VALUE");
    monitorProgram.process();
    System.setProperty(propertyName,oldProperty);

或者您想防止被调用的进程覆盖 system.property？
为什么不能手动设置系统属性？

This is not clear for me.

Do you want to overwrite a system property?
You can do this.

Overwrite the System.property before calling the external library method and when the method returns you can set the old System.property back

    final String propertyName = "Property";
    String oldProperty = System.getProperty(propertyName);
    System.setProperty(propertyName,"NEW_VALUE");
    monitorProgram.process();
    System.setProperty(propertyName,oldProperty);

Or do you want to prevent, that the called process overwrites the system.property?
And why you can not set the system property by hand?

回复收藏 0 原文