document和String的互转(jdom)
string-doc
SAXBuilder builder = new SAXBuilder(false);
Document doc = null;
StringReader xmlReader = new StringReader(xmlStr);//xmlStr为目标字符串
doc = builder.build(xmlReader);
xmlReader.close();


doc-string
Format format = Format.getCompactFormat();//格式化的方式，有三种的
format.setEncoding("UTF-8");
XMLOutputter xmlout = new XMLOutputter(format);
String xml = xmlout.outputString(doc);//doc为目标document