如何使用SAX初始化JAXB [英] How to initilize JAXB with SAX

问题描述

我正在尝试使用带有SAX的JAXB将xml编组为java对象.我在构造函数中编写了这段代码.

I am trying to unmarshall an xml to java object using JAXB with SAX. I wrote this code in the constructor.

logger.debug("Initializing jaxb...");
        try {
            jaxbContext = JAXBContext.newInstance(ProductInventory.class);
            jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
            reader = saxParserFactory.newSAXParser().getXMLReader();
            EntityResolver entityResolver = new EntityResolver() {
                @Override
                public InputSource resolveEntity(String publicId,
                        String systemId) {
                    return new InputSource(new StringReader(""));
                }
            };
            reader.setEntityResolver(entityResolver);
            logger.debug("Successfully initialized jaxb.");
        } catch (JAXBException | SAXException | ParserConfigurationException e) {
            logger.error("Exception while initializing JAXB", e);
        }

当多个请求到来时，reader对象是否存在任何问题?我是否必须始终获得reader的引用?我的意思是，每次取消编组操作都必须获得一个新的xml读取器吗?

Is there any problem with the reader object when multiple requests come? Do I have to get a reference of reader always? I mean for every unmarshall action do I have to get a new xml reader?

推荐答案

将SAX与JAXB一起使用时，您使用的是UnmarshallerHandler而不是Unmarshaller.

When using SAX with JAXB you leverage UnmarshallerHandler and not Unmarshaller.

UnmarshallerHandler unmarshallerHandler = unmarshaller.getUnmarshallerHandler();
reader.setContentHandler(unmarshallerHandler);
reader.parse(xml);
Foo foo = (Foo) unmarshallerHandler.getResult();

UnmarshallerHandler不是线程安全的，因此请确保没有共享线程.您可以使用相同的XMLReader

UnmarshallerHandler is not thread safe so make sure you don't have threads sharing it. You can parse multiple XML documents with the same XMLReader

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