Detailed explanation of XML parsing in Java

Let’s briefly talk about the first three methods:

DOM method: Personal understanding is similar to .net’s XmlDocument, which is not efficient when parsing, takes up memory, and is not suitable for parsing large XML;

SAX method: event-based parsing. When a certain part of xml is parsed, a specific event will be triggered. You can define what to do when the event is triggered in a custom parsing class; I personally feel that it is very different. method, I wonder if there is a similar method under the .Net system?

StAX method: I personally understand that it is similar to the .net XmlReader method, which is highly efficient, takes up less memory, and is suitable for parsing large XML;

However, the SAX method has been used before. This article mainly introduces JAXB. Only the main code is posted here:

import java.util.ArrayList; import java.util.List; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; public class ConfigParser extends DefaultHandler { private String currentConfigSection; public SysConfigItem sysConfig; public List interfaceConfigList; public List ftpConfigList; public List adapterConfigList; public void startDocument() throws SAXException { sysConfig = new SysConfigItem(); interfaceConfigList = new ArrayList(); ftpConfigList = new ArrayList(); adapterConfigList = new ArrayList(); } public void endDocument() throws SAXException { } public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { if (qName.equalsIgnoreCase("Item") && attributes.getLength() > 0) { if (currentConfigSection.equalsIgnoreCase("SysConfigItem")) { sysConfig = new SysConfigItem(attributes); } else if (currentConfigSection.equalsIgnoreCase("InterfaceConfigItems")) { interfaceConfigList.add(new InterfaceConfigItem(attributes)); } else if (currentConfigSection.equalsIgnoreCase("FtpConfigItems")) { ftpConfigList.add(new FtpConfigItem(attributes)); } else if (currentConfigSection.equalsIgnoreCase("AdapterConfigItems")) { adapterConfigList.add(new AdapterConfigItem(attributes)); } } else { currentConfigSection = qName; } } public void endElement(String uri, String localName, String qName) throws SAXException { } public void characters(char ch[], int start, int length) throws SAXException { } }

import java.lang.reflect.Field; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; import org.xml.sax.Attributes; public class ConfigItemBase { private static DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); public ConfigItemBase() { } /** * 目前只支持几种常用类型 如果需要支持其他类型，请修改这里的代码 * * @param attributes */ public ConfigItemBase(Attributes attributes) { Class cls = this.getClass(); Field[] fields = cls.getDeclaredFields(); for (Field field : fields) { String fieldType = field.getType().getSimpleName(); for (int i = 0; i < attributes.getLength(); i++) { if (attributes.getQName(i).equalsIgnoreCase(field.getName())) { field.setAccessible(true); try { if (fieldType.equalsIgnoreCase("String")) { field.set(this, attributes.getValue(attributes.getQName(i))); } else if (fieldType.equalsIgnoreCase("Integer")) { field.set(this, Integer.valueOf(attributes.getValue(attributes.getQName(i)))); } else if (fieldType.equalsIgnoreCase("Double")) { field.set(this, Double.valueOf(attributes.getValue(attributes.getQName(i)))); } else if (fieldType.equalsIgnoreCase("Date")) { field.set(this, GetDate(attributes.getValue(attributes.getQName(i)))); } else { System.out.println("Warning:Unhandler Field(" + field.getName() + "-" + fieldType + ")"); } } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } break; } } } } public String toString() { String result = ""; Class cls = this.getClass(); String classNameString = cls.getName(); result += classNameString.substring(classNameString.lastIndexOf('.') + 1, classNameString.length()) + ":"; Field[] fields = cls.getDeclaredFields(); for (Field field : fields) { try { result += field.getName() + "=" + field.get(this) + ";"; } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } } return result; } /** * 处理时间类型属性（时间格式要求为：yyyy-MM-dd hh:mm:ss） * * @param dateString * @return */ private static Date GetDate(String dateString) { Date date = null; try { date = dateFormat.parse(dateString); } catch (ParseException e) { e.printStackTrace(); } return date; } }

The following focuses on the most convenient one: JAXB (Java Architecture for XML Binding)
Here we use the more complex mobile BatchSyncOrderRelationReq interface XML as an example (I feel like I can solve this Basically enough for everyone), the message format is as follows (the CDATA content in SvcCont is the message body, which is disgusting):

  0100 0  BIP2B518 T2101518 0   BOSS routeType  XXXX routeValue    2013041017222313925676 2013041017222313925676 20130410172223                  rspType rspCode rspDesc    210001BIP2B518130410172223651627 2  210001BIP2B518130410172224341871  oprTime1 actionId1 brand1 effTime1 expireTime1 feeUserId1 destUserId1 actionId1 servType1 subServType1 spId1 spServId1 accessMode1  0      feeType1    210001BIP2B518130410172224420909  oprTime2 actionId2 brand2 effTime2 expireTime2 feeUserId2 destUserId2 actionId2 servType2 subServType2 spId2 spServId2 accessMode2  0      feeType2   ]]> 

The decoding code is as follows:

@XmlRootElement(name = "batchSyncOrderRelationReq") @XmlAccessorType(XmlAccessType.FIELD) public class BatchSyncOrderRelationReq extends BossMessage { @XmlElement(name = "msgTransactionID") private String msgTransactionId = ""; @XmlElement(name = "reqNum") private String reqNum = ""; @XmlElement(name = "reqBody") private List reqBodyList; public BatchSyncOrderRelationReq() { } public String getMsgTransactionId() { return this.msgTransactionId; } public void setMsgTransactionId(String msgTransactionId) { this.msgTransactionId = msgTransactionId; } public String getReqNum() { return this.reqNum; } public void setReqNum(String reqNum) { this.reqNum = reqNum; } public List getReqBodyList() { return this.reqBodyList; } public void setReqBodyList(List reqBodyList) { this.reqBodyList = reqBodyList; } @Override public BatchSyncOrderRelationReq Deserialized(String interBossXmlContent) throws BusinessException { try { // deserialized for head JAXBContext jaxbCxt4Head = JAXBContext.newInstance(MessageHead.class); Unmarshaller unmarshaller4Head = jaxbCxt4Head.createUnmarshaller(); MessageHead head = (MessageHead) unmarshaller4Head.unmarshal(new StringReader(interBossXmlContent)); // deserialized for SyncOrderRelationReq body JAXBContext jaxbCxt4Body = JAXBContext.newInstance(BatchSyncOrderRelationReq.class); Unmarshaller unmarshaller4Body = jaxbCxt4Body.createUnmarshaller(); BatchSyncOrderRelationReq batchSyncOrderRelationReq = (BatchSyncOrderRelationReq) unmarshaller4Body.unmarshal(new StringReader(head.getSvcCont().trim())); batchSyncOrderRelationReq.setHead(head); return batchSyncOrderRelationReq; } catch (JAXBException e) { throw new BusinessException("SyncOrderRelationReq.Deserialized() Error!(" + interBossXmlContent + ")", e); } } }

@XmlAccessorType(XmlAccessType.FIELD) public class BatchSyncOrderRelationReqBody { @XmlElement(name = "oprNumb") private String oprNumb = ""; @XmlElement(name = "subscriptionInfo") private SubscriptionInfo subscriptionInfo; public BatchSyncOrderRelationReqBody(){ } public BatchSyncOrderRelationReqBody(String oprNumb, SubscriptionInfo subscriptionInfo) { this.oprNumb = oprNumb; this.subscriptionInfo = subscriptionInfo; } public String getOprNumb() { return this.oprNumb; } public void setOprNumb(String oprNumb) { this.oprNumb = oprNumb; } public SubscriptionInfo getSubscriptionInfo() { return this.subscriptionInfo; } public void setSubscriptionInfo(SubscriptionInfo subscriptionInfo) { this.subscriptionInfo = subscriptionInfo; } }

@XmlAccessorType(XmlAccessType.FIELD) public class SubscriptionInfo { @XmlElement(name = "oprTime") private String oprTime = ""; @XmlElement(name = "actionID") private String actionId = ""; @XmlElement(name = "brand") private String brand = ""; @XmlElement(name = "effTime") private String effTime = ""; @XmlElement(name = "expireTime") private String expireTime = ""; @XmlElement(name = "feeUser_ID") private String feeUserId = ""; @XmlElement(name = "destUser_ID") private String destUserId = ""; @XmlElement(name = "actionReasonID") private String actionReasonId = ""; @XmlElement(name = "servType") private String servType = ""; @XmlElement(name = "subServType") private String subServType = ""; @XmlElement(name = "SPID") private String spId = ""; @XmlElement(name = "SPServID") private String spServId = ""; @XmlElement(name = "accessMode") private String accessMode = ""; @XmlElement(name = "feeType") private String feeType = ""; public SubscriptionInfo() { } public SubscriptionInfo( String oprTime, String actionId, String brand, String effTime, String expireTime, String feeUserId, String destUserId, String actionReasonId, String servType, String subServType, String spId, String spServId, String accessMode, String feeType) { this.oprTime = oprTime; this.actionId = actionId; this.brand = brand; this.effTime = effTime; this.expireTime = expireTime; this.feeUserId = feeUserId; this.destUserId = destUserId; this.actionReasonId = actionReasonId; this.servType = servType; this.subServType = subServType; this.spId = spId; this.spServId = spServId; this.accessMode = accessMode; this.feeType = feeType; } public String getOprTime() { return this.oprTime; } public void setOprTime(String oprTime) { this.oprTime = oprTime; } public String getActionId() { return this.actionId; } public void setActionId(String actionId) { this.actionId = actionId; } public String getBrand() { return this.brand; } public void setBrand(String brand) { this.brand = brand; } public String getEffTime() { return this.effTime; } public void setEffTime(String effTime) { this.effTime = effTime; } public String getExpireTime() { return this.expireTime; } public void setExpireTime(String expireTime) { this.expireTime = expireTime; } public String getFeeUserId() { return this.feeUserId; } public void setFeeUserId(String feeUserId) { this.feeUserId = feeUserId; } public String getDestUserId() { return this.destUserId; } public void setDestUserId(String destUserId) { this.destUserId = destUserId; } public String getActionReasonId() { return this.actionReasonId; } public void setActionReasonId(String actionReasonId) { this.actionReasonId = actionReasonId; } public String getServType() { return this.servType; } public void setServType(String servType) { this.servType = servType; } public String getSubServType() { return this.subServType; } public void setSubServType(String subServType) { this.subServType = subServType; } public String getSpId() { return this.spId; } public void setSpId(String spId) { this.spId = spId; } public String getSpServId() { return this.spServId; } public void setSpServId(String spServId) { this.spServId = spServId; } public String getAccessMode() { return this.accessMode; } public void setAccessMode(String accessMode) { this.accessMode = accessMode; } public String getFeeType() { return this.feeType; } public void setFeeType(String feeType) { this.feeType = feeType; } }

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