如何从servlet上下文中的jar文件中读取xml架构 [英] How to read xml schema from jar file in a servlet context

问题描述

我有一个maven库项目，其中包含一些处理xml消息的类。每当我收到其中一条消息时，我都会使用我编写的xml架构文件对其进行验证。对我进行验证的代码如下所示：

I have a maven library project with some classes to deal xml messages. Whenever I receive one of those messages I validate it using an xml schema file I have written. The code that does the validation for me looks like this:

public static Document parseXML(final String xml) throws JDOMException, IOException {
    SAXBuilder builder = new SAXBuilder("org.apache.xerces.parsers.SAXParser", true);
    builder.setFeature("http://apache.org/xml/features/validation/schema", true);
    URL location = CMPMessage.getClass().getResource(XML_SCHEMA_LOCATION);
    if (null == location) {
        throw new IOException("Unable to load schema definition file.");
    }
    builder.setProperty("http://apache.org/xml/properties/schema/external-schemaLocation",
            "http://www.mycompany.de/MyProtocol " + location);
    return builder.build(new StringReader(xml));
}

和 XML_SCHEMA_LOCATION 是像这样：

private static final String XML_SCHEMA_LOCATION = "/ConvertMessageProtocol.xsd";

.xsd文件位于 src / main / resources 并且，感谢maven，一切都很完美：当告诉maven制作包时，.xsd文件会包含在.jar中。
我做了一个简单的测试项目来检查是否真的会找到.xsd文件。源代码如下所示：

The .xsd file is in src/main/resources and, thanks to maven, everything works perfect: The .xsd file gets included in the .jar when tell maven to make a package. I made a simple test project to check whether the .xsd file will actually be found. The source looks like this:

import java.io.IOException;
import org.jdom.JDOMException;
import de.mycomp.MyMessage;


public class Main {
    public static void main(final String[] args) {
        try {
            MyMessage.parseXML(args[0]);
        }
        catch (JDOMException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

是的，xml会使用模式文件进行验证。

And yes, the xml will be validated using the schema file.

现在它来了：我想在servlet中使用我的小库（在tomcat中运行），但在那里，.xsd文件无法找到：（

Now here it comes: I want to use my little library in a servlet (running in tomcat), but there, the .xsd file can not be found :(

当然，我可以将.xsd文件直接存储在公司服务器上，并通过http检索它，但我认为包括它在.jar中是更好的解决方案，以确保libs和模式版本适合。

Of course, I could store the .xsd file somewhere else like directly on the companys server and retrieve it via http, but I think including it in the .jar is the better solution to make sure that the libs and the schemas version fit.

你有什么想法吗？

提前致谢：

Jim

推荐答案

assign

private static final String XML_SCHEMA_LOCATION = getPath("/ConvertMessageProtocol.xsd");

public static String getPath(String path){
  return UtilityClass.class.getResource(path).toString();
}

问题在于你的服务vlet app正在 / 中查找没有文件的文件。

The problem is your servlet app is looking for file at / where there is no file.

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