java - 如何在 JAXB 中获取输出(编码(marshal)处理)？

Question

我尝试了来自 here 的 hello world 示例而且我在我的程序中看不到任何输出(使用“java”命令时在控制台中)。我做错了什么吗？ marshal 函数的代码如下所示:

public void marshal() {
    try {
        JAXBElement<GreetingListType> gl =
            of.createGreetings( grList );
        JAXBContext jc = JAXBContext.newInstance( "hello" );
        Marshaller m = jc.createMarshaller();
        m.marshal( gl, System.out );
    } catch( JAXBException jbe ){
        // ...
    }
}

我也尝试过将输出放入这样的文件中:

public void marshal() {
    try {
        JAXBElement<GreetingListType> gl =
            of.createGreetings( grList );
        JAXBContext jc = JAXBContext.newInstance( "hello" );
        FileOutputStream fos = new FileOutputStream("plik.xml");
        Marshaller m = jc.createMarshaller();
        //m.marshal( gl, System.out );
        m.marshal(gl, fos);
        fos.close();
    } catch( JAXBException jbe ){
        // ...
    }
  catch( IOException ioe ){
    // ...
}
}

但是没有成功。你有什么解决办法吗？

编辑:打印 Stack Trace 后它给了我这个，看起来很有希望:

javax.xml.bind.JAXBException: "hello" doesnt contain ObjectFactory.class or jaxb.index
    at com.sun.xml.internal.bind.v2.ContextFactory.createContext(ContextFactory.java:186)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:148)
    at javax.xml.bind.ContextFinder.find(ContextFinder.java:310)
    at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:392)
    at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:357)
    at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:264)
    at Hello.marshal(Hello.java:28)
    at Hello.main(Hello.java:43)

我有 ObjectFactory，但对 jaxb.in​​dex 一无所知。有必要吗？它应该是什么样子？

Answer 1

我遇到了同样的问题。原来你需要改变这一行:

JAXBContext jc = JAXBContext.newInstance( "hello" );

但放置生成文件的实际完整包:

JAXBContext jc = JAXBContext.newInstance( "my.generated.package.etc" ); // or whatever.