Java中对XML的解析详解

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：
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 ListInterfaceConfigItem interfaceConfigList;
     public ListFtpConfigItem ftpConfigList;
     public ListAdapterConfigItem adapterConfigList;

     public void startDocument() throws SAXException {
         sysConfig = new SysConfigItem();
         interfaceConfigList = new ArrayListInterfaceConfigItem();
         ftpConfigList = new ArrayListFtpConfigItem();
         adapterConfigList = new ArrayListAdapterConfigItem();
     }

     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 {

     }
 }

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）：
代码如下：

?xml version="1.0" encoding="UTF-8" standalone="yes" ?
InterBOSS
    Version0100/Version
    TestFlag0/TestFlag
    BIPType
        BIPCodeBIP2B518/BIPCode
        ActivityCodeT2101518/ActivityCode
        ActionCode0/ActionCode
    /BIPType
    RoutingInfo
        OrigDomainBOSS/OrigDomain
        RouteTyperouteType/RouteType
        Routing
            HomeDomainXXXX/HomeDomain
            RouteValuerouteValue/RouteValue
        /Routing
    /RoutingInfo
    TransInfo
        SessionID2013041017222313925676/SessionID
        TransIDO2013041017222313925676/TransIDO
        TransIDOTime20130410172223/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
        RspTyperspType/RspType
        RspCoderspCode/RspCode
        RspDescrspDesc/RspDesc
    /Response
    SvcCont![CDATA[?xml version="1.0" encoding="UTF-8" standalone="yes"?
batchSyncOrderRelationReq
    msgTransactionID210001BIP2B518130410172223651627/msgTransactionID
    reqNum2/reqNum
    reqBody
        oprNumb210001BIP2B518130410172224341871/oprNumb
        subscriptionInfo
            oprTimeoprTime1/oprTime
            actionIDactionId1/actionID
            brandbrand1/brand
            effTimeeffTime1/effTime
            expireTimeexpireTime1/expireTime
            feeUser_IDfeeUserId1/feeUser_ID
            destUser_IDdestUserId1/destUser_ID
            actionReasonIDactionId1/actionReasonID
            servTypeservType1/servType
            subServTypesubServType1/subServType
            SPIDspId1/SPID
            SPServIDspServId1/SPServID
            accessModeaccessMode1/accessMode
            servParamInfo
                para_num0/para_num
                para_info
                    para_name/para_name
                    para_value/para_value
                /para_info
            /servParamInfo
            feeTypefeeType1/feeType
        /subscriptionInfo
    /reqBody
    reqBody
        oprNumb210001BIP2B518130410172224420909/oprNumb
        subscriptionInfo
            oprTimeoprTime2/oprTime
            actionIDactionId2/actionID
            brandbrand2/brand
            effTimeeffTime2/effTime
            expireTimeexpireTime2/expireTime
            feeUser_IDfeeUserId2/feeUser_ID
            destUser_IDdestUserId2/destUser_ID
            actionReasonIDactionId2/actionReasonID
            servTypeservType2/servType
            subServTypesubServType2/subServType
            SPIDspId2/SPID
            SPServIDspServId2/SPServID
            accessModeaccessMode2/accessMode
            servParamInfo
                para_num0/para_num
                para_info
                    para_name/para_name
                    para_value/para_value
                /para_info
            /servParamInfo
            feeTypefeeType2/feeType
        /subscriptionInfo
    /reqBody
/batchSyncOrderRelationReq]]/SvcCont
/InterBOSS

解码代码如下：
代码如下：

@XmlRootElement(name = "batchSyncOrderRelationReq")
 @XmlAccessorType(XmlAccessType.FIELD)
 public class BatchSyncOrderRelationReq extends BossMessageBatchSyncOrderRelationReq {

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

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

     @XmlElement(name = "reqBody")
     private ListBatchSyncOrderRelationReqBody 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 ListBatchSyncOrderRelationReqBody getReqBodyList() {
         return this.reqBodyList;
     }

     public void setReqBodyList(ListBatchSyncOrderRelationReqBody 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);
         }
     }

 }

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;
    }
}

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;
    }
}