先简单说下前三种方式：

DOM方式：个人理解类似.net的XmlDocument，解析的时候效率不高，占用内存，不适合大XML的解析；

SAX方式：基于事件的解析，当解析到xml的某个部分的时候，会触发特定事件，可以在自定义的解析类中定义当事件触发时要做得事情；个人感觉一种很另类的方式，不知道.Net体系下是否有没有类似的方式？

StAX方式：个人理解类似.net的XmlReader方式，效率高，占用内存少，适用大XML的解析；

不过SAX方式之前也用过，本文主要介绍JAXB，这里只贴下主要代码：
复制代码 代码如下:
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<InterfaceConfigItem> interfaceConfigList;
public List<FtpConfigItem> ftpConfigList;
public List<AdapterConfigItem> adapterConfigList;

public void startDocument() throws SAXException {
sysConfig = new SysConfigItem();
interfaceConfigList = new ArrayList<InterfaceConfigItem>();
ftpConfigList = new ArrayList<FtpConfigItem>();
adapterConfigList = new ArrayList<AdapterConfigItem>();
}

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 {

}
}

复制代码 代码如下:
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;
}
}

下面重点介绍一下最方便的:JAXB(Java Architecture for XML Binding)
这里用比较复杂的移动BatchSyncOrderRelationReq接口XML做为示例（感觉能解这个大家基本上够用了），报文格式如下（SvcCont里的CDATA内容是报文体，太恶心了）：
复制代码 代码如下:
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<InterBOSS>
<Version>0100</Version>
<TestFlag>0</TestFlag>
<BIPType>
<BIPCode>BIP2B518</BIPCode>
<ActivityCode>T2101518</ActivityCode>
<ActionCode>0</ActionCode>
</BIPType>
<RoutingInfo>
<OrigDomain>BOSS</OrigDomain>
<RouteType>routeType</RouteType>
<Routing>
<HomeDomain>XXXX</HomeDomain>
<RouteValue>routeValue</RouteValue>
</Routing>
</RoutingInfo>
<TransInfo>
<SessionID>2013041017222313925676</SessionID>
<TransIDO>2013041017222313925676</TransIDO>
<TransIDOTime>20130410172223</TransIDOTime>
<TransIDH></TransIDH>
<TransIDHTime></TransIDHTime>
</TransInfo>
<SNReserve>
<TransIDC></TransIDC>
<ConvID></ConvID>
<CutOffDay></CutOffDay>
<OSNTime></OSNTime>
<OSNDUNS></OSNDUNS>
<HSNDUNS></HSNDUNS>
<MsgSender></MsgSender>
<MsgReceiver></MsgReceiver>
<Priority></Priority>
<ServiceLevel></ServiceLevel>
<SvcContType></SvcContType>
</SNReserve>
<Response>
<RspType>rspType</RspType>
<RspCode>rspCode</RspCode>
<RspDesc>rspDesc</RspDesc>
</Response>
<SvcCont><![CDATA[<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<batchSyncOrderRelationReq>
<msgTransactionID>210001BIP2B518130410172223651627</msgTransactionID>
<reqNum>2</reqNum>
<reqBody>
<oprNumb>210001BIP2B518130410172224341871</oprNumb>
<subscriptionInfo>
<oprTime>oprTime1</oprTime>
<actionID>actionId1</actionID>
<brand>brand1</brand>
<effTime>effTime1</effTime>
<expireTime>expireTime1</expireTime>
<feeUser_ID>feeUserId1</feeUser_ID>
<destUser_ID>destUserId1</destUser_ID>
<actionReasonID>actionId1</actionReasonID>
<servType>servType1</servType>
<subServType>subServType1</subServType>
<SPID>spId1</SPID>
<SPServID>spServId1</SPServID>
<accessMode>accessMode1</accessMode>
<servParamInfo>
<para_num>0</para_num>
<para_info>
<para_name></para_name>
<para_value></para_value>
</para_info>
</servParamInfo>
<feeType>feeType1</feeType>
</subscriptionInfo>
</reqBody>
<reqBody>
<oprNumb>210001BIP2B518130410172224420909</oprNumb>
<subscriptionInfo>
<oprTime>oprTime2</oprTime>
<actionID>actionId2</actionID>
<brand>brand2</brand>
<effTime>effTime2</effTime>
<expireTime>expireTime2</expireTime>
<feeUser_ID>feeUserId2</feeUser_ID>
<destUser_ID>destUserId2</destUser_ID>
<actionReasonID>actionId2</actionReasonID>
<servType>servType2</servType>
<subServType>subServType2</subServType>
<SPID>spId2</SPID>
<SPServID>spServId2</SPServID>
<accessMode>accessMode2</accessMode>
<servParamInfo>
<para_num>0</para_num>
<para_info>
<para_name></para_name>
<para_value></para_value>
</para_info>
</servParamInfo>
<feeType>feeType2</feeType>
</subscriptionInfo>
</reqBody>
</batchSyncOrderRelationReq>]]></SvcCont>
</InterBOSS>

解码代码如下：
复制代码 代码如下:
@XmlRootElement(name = "batchSyncOrderRelationReq")
@XmlAccessorType(XmlAccessType.FIELD)
public class BatchSyncOrderRelationReq extends BossMessage<BatchSyncOrderRelationReq> {

@XmlElement(name = "msgTransactionID")
private String msgTransactionId = "";

@XmlElement(name = "reqNum")
private String reqNum = "";

@XmlElement(name = "reqBody")
private List<BatchSyncOrderRelationReqBody> 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<BatchSyncOrderRelationReqBody> getReqBodyList() {
return this.reqBodyList;
}

public void setReqBodyList(List<BatchSyncOrderRelationReqBody> 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);
}
}

}

复制代码 代码如下:
@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;
}
}

复制代码 代码如下:
@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;
}
}