xml的问题

今天加载xml文件的，并添加到Docuemnt里面去的时候发现一个问题。出现”Start of root element expected“的问题。开始以为是xml头文件的问题。但是把xml文件内的内容去掉后还是报出这个错误!然后我自己重新创建了一个xml文件。重新创建的xml文件有能正确的把xml放在Document里面去。 后来仔细对比两个文件，终于知道原因了。原来是编码的问题。这个错误让我很无语啊。找了我一上午。一个是UTF-8格式，一个是UTF-8无DOM的格式。 DocumentBuilder加载xml的时候，默认格式是UTF-8格式。但是，我的文件是UTF-8格式的还错误了。竟然用UTF-8无DOM格式正确了。百思不得其解。后来查了一下UTF-8和UTF-8无DOM的区别。

 

BOM——Byte Order Mark，就是字节序标记

UTF-8不需要BOM来表明字节顺序，但可以用BOM来表明编码方式。字符"ZERO WIDTH NO-BREAK SPACE"的UTF-8编码是EF BB BF。所以如果接收者收到以EF BB BF开头的字节流，就知道这是UTF-8编码了。

 

UTF- 8编码的文件中，BOM占三个字节。如果用记事本把一个文本文件另存为UTF-8编码方式的话，用UE打开这个文件，切换到十六进制编辑状态就可以看到开 头的FFFE了。这是个标识UTF-8编码文件的好办法，软件通过BOM来识别这个文件是否是UTF-8编码，很多软件还要求读入的文件必须带BOM。可 是，还是有很多软件不能识别BOM。

还是不太懂。麻烦知道的人赐教。谢谢。

<?xml version="1.0" encoding="UTF-8"?>
<page>
	<!--  hotelSearch  request -->
	<searchConditions>
		<cityCode>PAR</cityCode>
		<checkInDate>20121103</checkInDate>
		<checkOutDate>20121104</checkOutDate>
		<hotelName>戴斯</hotelName>
		<rankCode>5</rankCode>
		<roomCount>4</roomCount>
	</searchConditions>
	<!-- hotelSearch  response -->
	<hotelInfos>
		 <hotelTitle>
			<lowestPrice>lowestPrice</lowestPrice>
		</hotelTitle>
		<hotelInfo>
			<ID>886841</ID>
			<name>广州戴斯酒店</name>
			<englishName>Guangzhou dace hotel</englishName>
			<rankCode>3</rankCode>
			<positionCode>No.1 Tuhua Road Huazhou Street</positionCode>
			<lowestPrice>400.9</lowestPrice>
			<rooms>
				<room>
					<roomId>435453671</roomId>
					<roomName>SINGLE</roomName>
					<roomType>ROOM</roomType>
					<bedType>1 double bed</bedType>
					<amount>
						<currencyCode>AUD</currencyCode>
						<ratePlanCode>123</ratePlanCode>
						<ratePlanType>M</ratePlanType>
						<rateAccessCode>648097791</rateAccessCode>
						<amountBeforeTax>38.18</amountBeforeTax>
						<tax>4.58</tax>
						<commisionRate>1.14</commisionRate>
						<amountAfterTax>43.9</amountAfterTax>
					</amount>
					<describe>Single Room - 1 double bed</describe>
				</room>
			</rooms>
			<introduction>Surrounded by Guangzhou University City, Yingzhou Ecological Park,International Biological Island, Pazhou International Exhibition Center, Sanflowery Hotel is an ideal place for business and leisure,with the comfortable environment about 30000 square meters.</introduction>
			<imageURL/>
			<address>No.1 Tuhua Road Huazhou Street</address>
			<establishs>
				<establish>
					<element>Meeting/Banquet facilities</element>
					<element>Internet access</element>
					<element>Business centre</element>
					<element>Conference facilities</element>
					<element>High speed internet</element>
					<element>Restaurant</element>
					<element>Concierge</element>
					<element>Room service</element>
				</establish>
			</establishs>
		</hotelInfo>
</hotelInfos>
</page>

 

package com.csair.util.test;

import java.io.*;
import java.nio.charset.Charset;

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

import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;



public class ReadFileUtil {
	
	public static String getStrFromFile(String filePath){
		 StringBuffer   buf=null;//the   intermediary,   mutable   buffer     
	       BufferedReader   breader = null;//reader   for   the   template   files     
	       try       
	       {     
	         breader = new BufferedReader(new InputStreamReader(new FileInputStream((filePath)),Charset.forName("utf-8")));  
	             buf   =   new   StringBuffer();     
	             while(breader.ready())       
	                   buf.append((char)breader.read());     
	             breader.close();     
	       }//try     
	       catch(Exception   e)       
	       {     
	        e.printStackTrace();  
	       }//catch     
	       return   buf.toString();     
	      
	}
	
	
	public static void main(String[] args){
		//System.out.print(getStrFromFile("C://Users/Administrator/Desktop/hotelSearch.xml"));
		DocumentBuilder domBuilder;
		try {
			domBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
			String arr= ReadFileUtil.getStrFromFile("C://Users/Administrator/Desktop/hotelSearch.xml");
			Document doc=domBuilder.parse(new InputSource(new StringReader(arr.toString())));
			System.out.println(doc.toString());
		} catch (ParserConfigurationException e) {
			e.printStackTrace();
		} catch (FactoryConfigurationError e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}