核心代碼：
package com.ddatsh; import java.io.IOException;import java.io.StringReader;import java.io.StringWriter;import java.io.UnsupportedEncodingException; import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.io.OutputFormat;import org.dom4j.io.SAXReader;import org.dom4j.io.XMLWriter; public class XmlFormat { public static String format(String str) throws Exception { SAXReader reader = new SAXReader(); // System.out.println(reader); // 註釋：創建一個串的字符輸入流StringReader in = new StringReader(str); Document doc = reader.read(in); // System.out.println(doc.getRootElement()); // 註釋：創建輸出格式OutputFormat formater = OutputFormat.createPrettyPrint(); //formater=OutputFormat.createCompactFormat(); // 註釋：設置xml的輸出編碼formater.setEncoding("utf-8"); // 註釋：創建輸出(目標) StringWriter out = new StringWriter(); // 註釋：創建輸出流XMLWriter writer = new XMLWriter(out, formater); // 註釋：輸出格式化的串到目標中，執行後。格式化後的串保存在out中。 writer.write(doc); writer.close(); System.out.println(out.toString()); // 註釋：返回我們格式化後的結果return out.toString(); } public static void main(String[] args) throws Exception { String head="<?xml version=/"1.0/" encoding=/"GBK/"?>"; String str = "<RequestData><HeadData><UserCode>sh1_admin</UserCode><UserName>sh1_admin</UserName><UserCompanyCode>3107</UserCompanyCode><UserCompanyName>上海分公司一部</UserCompanyName><RequestType>03</RequestType></HeadData><BodyData><ReportId>113100000033</ReportId><Insurant>a5rfg87</Insurant><NumberPlate>滬E78612</NumberPlate><EngineModel></EngineModel><CarVin></CarVin><AccidentDate>2011-02-25 15:07:00</AccidentDate><ReportDate>2011-02-25 15:07:00</ReportDate><Province>310000</Province><City>310100</City><District></District><AccidentPlace>1</AccidentPlace><AccidentLongitude></AccidentLongitude><AccidentLatitude></AccidentLatitude><SurveyLongitude></SurveyLongitude><SurveyLatitude></SurveyLatitude><SceneReportFlag></SceneReportFlag><Reporter></Reporter><ReporterTel></ReporterTel><SurveyPlace></SurveyPlace><OperatorId>3525</OperatorId><OperatorName>sh_admin</OperatorName><ReportDealId>30000800</ReportDealId><ReportDealName>江蘇分公司</ReportDealName><CompanyName></CompanyName><CustomerTypeCode></CustomerTypeCode><ForcePolicyId>a5rfg87a5rfg87a5rfg87</ForcePolicyId><BizPolicyId></BizPolicyId><Index>0</Index><FieldName>5</FieldName></BodyData></RequestData>"; // System.out.println(str); format(str); } }oschina用的在線格式化xml的工具就是使用此段代碼。