DocumentBuilderFactory   factory   =   DocumentBuilderFactory.newInstance(); 
Document   doc   =   factory.newDocumentBuilder().parse(new   InputSource(new   StringReader(fragment)));

package com.ss;

import java.io.StringReader;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;

public class Dom4jTest
{
    public static void main(String[] args)
    {

        try
        {
            String xml = "<?xml version=\"1.0\" encoding=\"gb2312\"?><root></root>";
            SAXReader reader = new SAXReader();
            Document doc = reader.read(new StringReader(xml));
            // 然后进行解析
        } catch (DocumentException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}