判断字符串是否是xml格式

XML是纯文本，你要判断它整个是否正确格式，相当于读入全部文件整个进行字符串分析更耗资源！

最简单的方法就是用异常判断。

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

private static boolean isXmlDocument(String rtnMsg){

boolean flag = true;
try {
        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
        builder.parse( new InputSource( new StringReader( rtnMsg )));
} catch (Exception e) {
flag = false;
}
return flag;
}