问题描述

我将 jaxb 用于我的应用程序配置

I am using jaxb for my application configurations

我觉得我在做一些非常不正当的事情，我正在寻找一种不需要实际文件或此交易的方法.

I feel like I am doing something really crooked and I am looking for a way to not need an actual file or this transaction.

正如你在代码 I 中看到的:

As you can see in code I:

1.从我的 JaxbContext 中创建一个模式到一个文件中(实际上来自我的类​​注释)2.设置此模式文件以便在我解组时允许真正的验证

1.create a schema into a file from my JaxbContext (from my class annotation actually) 2.set this schema file in order to allow true validation when I unmarshal

JAXBContext context = JAXBContext.newInstance(clazz);
Schema mySchema = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(schemaFile);
jaxbContext.generateSchema(new MySchemaOutputResolver()); // ultimately creates schemaFile   
Unmarshaller u = m_context.createUnmarshaller();
u.setSchema(mySchema);
u.unmarshal(...);

你们中有人知道如何验证 jaxb，而无需在我的计算机中创建架构文件吗?

do any of you know how I can validate jaxb without needing to create a schema file that sits in my computer?

我是否需要创建一个模式进行验证，当我通过 JaxbContect.generateSchema 获得它时它看起来是多余的?

Do I need to create a schema for validation, it looks redundant when I get it by JaxbContect.generateSchema ?

你是怎么做到的?

推荐答案

关于上面ekeren的解决方案，在单线程中使用PipedOutputStream/PipedInputStream并不是一个好主意，以免溢出缓冲区导致死锁.ByteArrayOutputStream/ByteArrayInputStream 有效，但如果您的 JAXB 类生成多个模式(在不同的命名空间中)，您需要多个 StreamSource.

Regarding ekeren's solution above, it's not a good idea to use PipedOutputStream/PipedInputStream in a single thread, lest you overflow the buffer and cause a deadlock. ByteArrayOutputStream/ByteArrayInputStream works, but if your JAXB classes generate multiple schemas (in different namespaces) you need multiple StreamSources.

我最终得到了这个:

JAXBContext jc = JAXBContext.newInstance(Something.class);
final List<ByteArrayOutputStream> outs = new ArrayList<ByteArrayOutputStream>();
jc.generateSchema(new SchemaOutputResolver(){
    @Override
    public Result createOutput(String namespaceUri, String suggestedFileName) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        outs.add(out);
        StreamResult streamResult = new StreamResult(out);
        streamResult.setSystemId("");
        return streamResult;
    }});
StreamSource[] sources = new StreamSource[outs.size()];
for (int i=0; i<outs.size(); i++) {
    ByteArrayOutputStream out = outs.get(i);
    // to examine schema: System.out.append(new String(out.toByteArray()));
    sources[i] = new StreamSource(new ByteArrayInputStream(out.toByteArray()),"");
}
SchemaFactory sf = SchemaFactory.newInstance( XMLConstants.W3C_XML_SCHEMA_NS_URI );
m.setSchema(sf.newSchema(sources));
m.marshal(docs, new DefaultHandler());  // performs the schema validation

这篇关于我如何在 jaxb 中解组并在不使用显式模式文件的情况下享受模式验证的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！