一键解析XML文件(利用Digester实现可配置)-阿里云开发者社区

大部分程序员，平时工作中除了与Bug相伴之外，想必也会很多种多样的文件打交道吧。当然,XML 就是其中之一，获取交互数据,创建规则等等，都离不开他。XML是个非常强大的描述语言，相比而言,txt之流则功力较弱了些。

XML那么重要，单解析XML的工作却繁杂无聊。原因如下：解析XML工具繁杂,每个人掌握的东西不一样;学习新工具又浪费时间;解析规则只是个体力活。

程序员的辛苦，也就体现于此了。一般程序员总是抱怨忙啊忙，累啊累。我们作为程序员来说，更应该想一想想法设法吧东西提炼一下，减少重复的工作。说这些题外话，是有原因的。我现在的大部分同事，加班加点在哪加班，貌似很辛苦，看一下他们的工作，让人很无奈。代码是一大段一大段的写，确实一晚上写个百十行，是非常“有成就感”的。

如生成XML 文件，用拼串的方式实现。一个小小的xml，往往都50多行。让人很无语。

解析XML, 往往都需要有一套解析规则。而我们可以动态创建解析规则。让后根据规则将xml文件数据放到Map中。思路简单至极。其他扩展，暂时不考虑。

主要步骤分为2部分

第一部分使用Digester实现可配置的规则树结构

1) 规则节点对象

public     class Node{
   private String nodeName;
   private List children = new ArrayList();
   /**
    * 属性列表,以逗号分隔
    */
   private String attrs="";

   public String getAttrs() {
     return attrs;
  }
   public void setAttrs(String values) {
     this.attrs= values;
  }
   public String getNodeName() {
     return nodeName;
  }
   public void setNodeName(String nodeName) {
     this.nodeName = nodeName;
  }
   public List getChildren() {
     return children;
  }
   public void addChildren(Node node) {
     this.children.add(node);
  }
  @Override
   public String toString() {

     return this.nodeName+ ":"+ "have"+ this.getChildren().size()+ "子节点";
  }
}

(2) 定义xml 解析规则文件，当然也可以写编码实现。

<? xml version ="1.0" ?>
<!DOCTYPE digester-rules PUBLIC "-//Jakarta Apache //DTD digester-rules XML V1.0//EN" "http://jakarta.apache.org/commons/digester/dtds/digester-rules.dtd">
< digester-rules >
 < pattern value ="root" >
 < object-create-rule classname ="com.aisino.common.parse.Node" />
 < set-properties-rule />
 < set-next-rule methodname ="add" />

 < pattern value ="level1" >
 < object-create-rule classname ="com.aisino.common.parse.Node" />
 < set-properties-rule />
 < set-next-rule methodname ="addChildren" />
 < pattern value ="level2" >
 < object-create-rule classname ="com.aisino.common.parse.Node" />
 < set-properties-rule />
 
 < pattern value ="level3" >
 < object-create-rule classname ="com.aisino.common.parse.Node" />
 < set-properties-rule />
 < set-next-rule methodname ="addChildren" />
 < pattern value ="level4" >
 < object-create-rule classname ="com.aisino.common.parse.Node" />
 < set-properties-rule />
 < set-next-rule methodname ="addChildren" />
 < pattern value ="level5" >
 < object-create-rule classname ="com.aisino.common.parse.Node" />
 < set-properties-rule />
 < set-next-rule methodname ="addChildren" />
 </ pattern >
 </ pattern >
 </ pattern >

 < set-next-rule methodname ="addChildren" />
 </ pattern >
 </ pattern >
 </ pattern >
</ digester-rules >

3) 规则解析类RuleLoader

public class RuleLoader {
 private static final Log logger = LogFactory.getLog(RuleLoader. class);
 private URL digesterRulesURL;
 private URL fileURL;
 public RuleLoader(String rulePath,String filePath){
 digesterRulesURL= getURL(rulePath);
 fileURL = getURL(filePath);
// digesterRulesURL= getClass().getClassLoader().getResource(rulePath);
 }
 public RuleLoader(URL digesterRulesURL,URL fileURL){
 this.digesterRulesURL = digesterRulesURL;
 this.fileURL = fileURL;
 }

 public static RuleLoader getXmlRuleLoader(String filePath){
 URL url = getURL( "classpath:com/aisino/common/parse/xml-rules.xml");
 return new RuleLoader(url,getURL(filePath));
 }

 /**
 *
 * 自定义指定规则 
 * 需要对Digester 解析规则熟悉
 * @return
 */
 public List parseRules(){
 ClassLoader classLoader = getClass().getClassLoader();
 Object root = new ArrayList();
 try {
 DigesterLoader.load(digesterRulesURL, classLoader, fileURL,root);
 } catch (IOException e) {
 logger.error( "IOException");
 } catch (SAXException e) {
 logger.error( "SAX error");
 } catch (DigesterLoadingException e) {
 logger.error( "an error occurs while parsing XML into Digester rules");
 }
 return (List)root;
 }

 /**
 *
 * 解析XML数据，并将数据保存至Map
 * 最多支持5级
 * XML节点:主要表示root、level1,level2,level3,level4,level5 
 * for example: 
 * <root nodeName="dataExchangePackage"> 
 * <level1 nodeName="envelopeInfo"> 
 * <level2 nodeName="sourceID" /> 
 * <level2 nodeName="destinationID" /> 
 * <level2 nodeName="destinationAppID" /> 
 * <level2 nodeName="businessType" /> 
 * <level2 nodeName="globalBusinessID" /> 
 * </level1>
 * <level1>
 * ...
 * </level1>
 </root>
 
 约定 ${}为节点对应nodeName值
 ${root} = dataExchangePackage
 ${level1}==envelopeInfo
 ${level2}==sourceID...
 * @param input
 * @return Map
 * 从map 获取值
 * 如果key 是叶子节点：则返回string,反之,为Map
 * 如果想取sourceID的值，则key=/dataExchangePackage/envelopeInfo/sourceID
 */
 public static Map reParseRules(String filePath,InputStream input){
 List rules = RuleLoader.getXmlRuleLoader(filePath).parseRules();
 if(rules != null && rules.size()>0){
 Digester digester = new Digester();
 Node root=(Node)rules.get(0); //根节点
 MapSetNextRule rule = new MapSetNextRule( "put");
 addRule2Dister(digester, root,"", rule, true);
 try {
 Map valueMap = new HashMap();
 Map parseMap = (Map)digester.parse(input);
 valueMap.putAll(parseMap);
 afterRootMap(parseMap,valueMap,"");
 return valueMap;
 } catch (IOException e) {
 e.printStackTrace();
 } catch (SAXException e) {
 e.printStackTrace();
 } finally{
 digester= null;
 }
 }
 return null;
 }

 private static void afterRootMap(Map valueMap,Map destMap,String pattern){
 String fullPattern="";

 Iterator keys = valueMap.keySet().iterator();
 while(keys.hasNext()){
 Object key = keys.next();
 Object v = valueMap.get(key);
 fullPattern= pattern+ "/"+key;
 if(v instanceof Map){
 afterRootMap((Map)v,destMap,fullPattern);
 } else{
 logger.debug(fullPattern+ ">>>>对应元素>"+v+ " 放入返回栈中");
 destMap.put(fullPattern, v);
 }
 }
 }

 private static URL getURL(String resourceLocation){
 try {
 if (resourceLocation.startsWith(ResourceHelper.CLASSPATH_URL_PREFIX)) {
 return ResourceHelper.getURL(resourceLocation);
 } else if(resourceLocation.startsWith(ResourceHelper.FILE_URL_PREFIX)) {
 resourceLocation = StringUtils.replace(resourceLocation, ResourceHelper.FILE_URL_PREFIX, "");
 return new File(resourceLocation).toURI().toURL();
 }
 } catch (Exception e) {
 logger.error( "解析XML路径时,出错");
 }
 return null;
 }


/**
* 递归添加解析规则
* @param digester
* @param node ：当前节点
* @param pattern:规则
* @param rule:支持map添加
* @param isRoot 是否为根节点
*/
private static void addRule2Dister(Digester digester,Node node,String pattern,MapSetNextRule rule, boolean isRoot){
 String fullPattern="";
 if(StringUtils.isNotBlank(pattern)){
 fullPattern = pattern+ "/"+node.getNodeName();
 } else{
 fullPattern = node.getNodeName();
 }
 if(node.getChildren().size()>0){
 logger.debug( " add rules >>> digester.addObjectCreate("+fullPattern+ ", HashMap.class);");
 digester.addObjectCreate(fullPattern, HashMap. class);
 if(StringUtils.isNotBlank(node.getAttrs())){
 String[] attrs =StringUtils.split(node.getAttrs(), ",");
 logger.debug(fullPattern+ "有属性:"+ToStringBuilder.reflectionToString(attrs));
 for( int i=0;i<attrs.length;i++){
 String attr= attrs[i];
 logger.debug( " add rules >>> digester.addCallMethod("+fullPattern+ ",\"put\", 2)");
 logger.debug( " add rules >>> digester.addObjectParam("+fullPattern+ ",0, "+attr+ ")");
 logger.debug( " add rules >>> digester.addCallParam("+fullPattern+ ",1, "+attr+ ")");
 digester.addCallMethod(fullPattern, "put", 2);
 digester.addObjectParam(fullPattern, 0, attr);
 digester.addCallParam(fullPattern, 1,attr);
 }
 }
 if(!isRoot){ //不是根节点
 logger.debug( " add rules >>> digester.addRule("+fullPattern+ ", rule);");
 digester.addRule(fullPattern, rule);
 }
 for( int i=0;i<node.getChildren().size();i++){
 Node child = (Node)node.getChildren().get(i);
 addRule2Dister(digester,child,fullPattern,rule, false);
 }

 } else{
 //叶子节点
 logger.debug( "add rules >>> digester.addCallMethod("+fullPattern+ ", \"put\", 2)");
 digester.addCallMethod(fullPattern, "put", 2);
 logger.debug( "add rules >>> digester.addObjectParam("+fullPattern+ ",0, "+node.getNodeName()+ ")");
 digester.addObjectParam(fullPattern, 0, node.getNodeName());
 logger.debug( "add rules >>> digester.addCallParam("+fullPattern+ ",1)");
 digester.addCallParam(fullPattern, 1);
 }
 }
...
}

XML阅读器

public class XmlReader {
   private static final Log logger = LogFactory.getLog(XmlReader. class);
   private String rulePath;
   private String filePath;
   private RuleLoader rule;
   public XmlReader(String rulePath){
     this.rulePath = rulePath;
  }
   public List read(String filePath){
        rule = new RuleLoader( this.rulePath,filePath);
         return rule.parseRules();
  }
...
}

测试类

      public static void main(String args[]) throws Exception{
      InputStream resourceAsStream = Thread.currentThread().getContextClassLoader().getResourceAsStream( "com/aisino/common/parse/101R.xml");
      Map m = RuleLoader.reParseRules( "classpath:com/aisino/common/parse/xml-value-example.xml",resourceAsStream);
      System.out.println(m.get( "/dataExchangePackage/envelopeInfo/destinationID"));
      System.out.println(m.get( "/dataExchangePackage/transferInfo/age"));
      System.out.println(m.get( "/dataExchangePackage/transferInfo/sex"));
        }

测试规则文件（定义XML解析规则）

暂时只支持5级。当然可以无限增加至6级别,8级...

Digester 好想不支持通配符吧。在这一点确实没有做到充分的可扩展。但是5级相当可以满足应用了

<? xml version ="1.0" ?>
< root nodeName ="dataExchangePackage" >
< level1 nodeName ="envelopeInfo" >
 < level2 nodeName ="sourceID" />
 < level2 nodeName ="destinationID" />
 < level2 nodeName ="destinationAppID" />
 < level2 nodeName ="businessType" />
 < level2 nodeName ="globalBusinessID" />
</ level1 >
< level1 nodeName ="transferInfo" attrs ="age,sex" >
 < level2 nodeName ="senderID" />
 < level2 nodeName ="receiverID" />
 < level2 nodeName ="isRetry" />
 < level2 nodeName ="sendTime" />
 < level2 nodeName ="messageID" />
 < level2 nodeName ="sourceMessageID" />
</ level1 >
< level1 nodeName ="contentControl" >
 < level2 nodeName ="zip" >
 < level3 nodeName ="isZip" />
 </ level2 >
 < level2 nodeName ="encrypt" >
 < level3 nodeName ="isEncrypt" />
 </ level2 >
 < level2 nodeName ="code" >
 < level3 nodeName ="isCode" />
 </ level2 >
</ level1 >
< level1 nodeName ="packageInfo" >
 < level2 nodeName ="subPackage" >
 < level3 nodeName ="sequence" />
 < level3 nodeName ="content" >
 < level4 nodeName ="dj_nsrxx" >
 < level5 nodeName ="nsrsbh" />
 < level5 nodeName ="swjg_dm" />
 < level5 nodeName ="nsrdzdah" />
 < level5 nodeName ="nsrmc" />
 < level5 nodeName ="zjhm" />
 < level5 nodeName ="scjydz" />
 < level5 nodeName ="bsrmc" />
 < level5 nodeName ="dhhm" />
 < level5 nodeName ="djzclx_dm" />
 < level5 nodeName ="nsrzt_dm" />
 < level5 nodeName ="nsr_swjg_dm" />
 </ level4 >
 </ level3 >
 </ level2 >
</ level1 >
< level1 nodeName ="returnState" >
 < level2 nodeName ="returnCode" > </ level2 >
 < level2 nodeName ="returnMessageID" > </ level2 >
 < level2 nodeName ="returnMessage" > </ level2 >
</ level1 >
</ root >

测试数据

<? xml version ="1.0" encoding ="GBK" ?>
< dataExchangePackage xmlns ="http://www.chinatax.gov.cn/tirip/dataspec" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://www.chinatax.gov.cn/tirip/dataspec/dataExchangePackage.xsd" version ="SW5001" >
 < envelopeInfo >
 < sourceID >SJ </ sourceID >
 < destinationID >YD </ destinationID >
 < destinationAppID >SJQZ </ destinationAppID >
 < businessType >WLFP101 </ businessType >
 < globalBusinessID >SJWLFP1012012011100184241 </ globalBusinessID >
 </ envelopeInfo >
 < transferInfo age ="88777" sex ="男" >
 < senderID >SJ </ senderID >
 < receiverID >YD </ receiverID >
 < isRetry />
 < sendTime >2012-01-11 13:14:57:759 </ sendTime >
 < messageID >SJWLFP1012012011100184241 </ messageID >
 < sourceMessageID />
 </ transferInfo >
 < contentControl >
 < zip >
 < isZip >false </ isZip >
 </ zip >
 < encrypt >
 < isEncrypt >false </ isEncrypt >
 </ encrypt >
 < code >
 < isCode >false </ isCode >
 </ code >
 </ contentControl >
 < packageInfo >
 < subPackage >
 < sequence >1 </ sequence >
 < content >
 < dj_nsrxx >
 < nsrsbh >350583729702365 </ nsrsbh >
 < swjg_dm >13505833100 </ swjg_dm > < xgrq />
 < nsrdzdah >350502001008324 </ nsrdzdah >
 < nsrmc >南安市水头康利石材有限公司 </ nsrmc >
 < zjhm >130302610511351 </ zjhm >
 < scjydz >南安市水头镇西锦村 </ scjydz >
 < bsrmc >陈姿颖 </ bsrmc >
 < dhhm >6981988 </ dhhm >
 < djzclx_dm >230 </ djzclx_dm >
 < nsrzt_dm >21 </ nsrzt_dm >
 < nsr_swjg_dm >13505833100 </ nsr_swjg_dm >
 </ dj_nsrxx >
 </ content >
 </ subPackage >
 </ packageInfo >
 < returnState >
 < returnCode >00 </ returnCode >
 < returnMessageID >YDWLFP1012012011100000001 </ returnMessageID >
 < returnMessage >成功 </ returnMessage >
 </ returnState >
</ dataExchangePackage >

测试结果

/dataExchangePackage/envelopeInfo/destinationID>>>>YD
/dataExchangePackage/transferInfo/age>>>88777
/dataExchangePackage/transferInfo/age>>>男

本文转自 randy_shandong 51CTO博客，原文链接：http://blog.51cto.com/dba10g/1179244，如需转载请自行联系原作者

一键解析XML文件(利用Digester实现可配置)

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