Java如何在同一方法中使用XMLStreamReader和XMLStreamWriter

问题描述

我使用XMLStreamReader读取xml文件。我想复制此实际文件并在此文件中添加一些节点：

XMLInputFactory factory = XMLInputFactory.newInstance();
    
    try {
        XMLStreamReader dataxML = factory.createXMLStreamReader(new FileReader(path));
        XMLStreamWriter dataWXML = (XMLStreamWriter) factory.createXMLStreamReader(new FileReader(path));
        
        while (dataxML.hasNext())
        {
            int type = dataxML.next();
            switch(type)
            {
                case XMLStreamReader.START_ELEMENT:
                    
                     dataWXML.writeStartElement("apple");
                        
                    break;
            }

        }

当我尝试运行时，出现此错误：Exception in thread "main" java.lang.classCastException: class com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl cannot be cast to class javax.xml.stream.XMLStreamWriter

做到这一点的最佳方法是什么？

解决方法

使用XMLOutputFacotry来创建输出流

XMLInputFactory factory = XMLInputFactory.newInstance();
XMLOutputFactory outFactory = XMLOutputFactory.newInstance();
try {
    XMLStreamReader dataXML = factory.createXMLStreamReader(new FileReader(path));
    XMLStreamWriter dataWXML = factory.createXMLStreamWriter(new FileReader(otherPath));
    ...
}
    
       

请注意输出文件使用其他路径

,

此行是您的问题：

    XMLStreamWriter dataWXML = (XMLStreamWriter) factory.createXMLStreamReader(new FileReader(path));

您根本无法将XMLStreamReader强制转换为XMLStreamWriter。它们是单独的类，XMLStreamWriter并非从XMLStreamReader扩展而来。