利用webservice获得xml信息可能出现一些影响

场景：服务端使用java开发，发布web服务，客户端使用delphi开发展示数据，两者通过webservice来通讯。

在测试中，客户端请求一个xml文档(该文档存放于oracle数据库中，CLOB型)，发现有时候能正常取到，有时候取到的数据以xml方式解析解析不了。

而我使用java客户端来请求该数据时，又能正常得到所有xml数据，和库中一样。为了彻底解决这个问题，写了一个测试的webservice接口。

java 代码

public class TestService {
    public TestService() {
    }

    public String getMessage() {
            return message;
    }
}

这里的message其实是一个xml文档（由于不能贴在里，会丢信息原来信息无法阅读，所以在后面贴出）。

若message赋值为xml_a时，delphi客户端没有任何问题，能得到正常结果。xml_a内容如下：

xml 代码

String xml_a =
    "<<!---->xml version=\"1.0\" encoding=\"UTF-8\"?>"
        + " <bCCH_BCH_Message>xxyyzz"
        + " <message>"
        + "   <sfn_Prime>25sfn_Prime>"
        + "   <payload>"
        + "      <completeSIB_List>"
        + "         <element>"
        + "            <sib_Type>systemInformationBlockType7sib_Type>"
        + "            <sib_Data_variable>01 80 80sib_Data_variable>"
        + "         element>"
        + "         <element>"
        + "            <sib_Type>schedulingBlock1sib_Type>"
        + "            <sib_Data_fixed>08 0D B0 1D 05 80 C4 4C 06 A0sib_Data_fixed>"
        + "         element>"
        + "      completeSIB_List>"
        + "   payload>"
        + " message>"
        + " <xxyyzz1>xxyyzz123xxyyzz1>"
        + " <xxyyzz1>xxyyzz987xxyyzz1>"
        + " bCCH_BCH_Message>";

用tcptrace工具得到的返回结果，<写为<,>为>,&为&，这是由于是传输的数据就是以XML，在这个xml文档内再包含其他xml内容时需要转义。

当xml_b（比较长）赋值给message时，如下：

xml 代码

String xml_b =
"<!---->xml version=\"1.0\" encoding=\"UTF-8\"?>"
    + "<uL_DCCH_Message>                        "
    + "<xyz>"
    +"  <a>1a>"
    +"  <b>2b>"
    +"  <c>3c>"
    +"  <d>4d>"
    +"  <e>5e>"
    +"  <f>6f>"
    +"  <g>7g>"
    +"  <h>8h>"
    +"  <i>9i>"
    +"  <j>10j>"
    +"  <k>11k>"
    +"  <l>12l>"
    +"  <m>13m>"
    +"xyz>"
    + "   <message>"
    + "      <rrcConnectionSetupComplete>"
    + "         <rrc_TransactionIdentifier>0rrc_TransactionIdentifier>"
    + "         <startList>"
    + "            <element>"
    + "               <cn_DomainIdentity>cs_domaincn_DomainIdentity>"
    + "               <start_Value>00000000000000000100start_Value>"
    + "            element>"
    + "            <element>"
    + "               <cn_DomainIdentity>ps_domaincn_DomainIdentity>"
    + "               <start_Value>00000000000000010010start_Value>"
    + "            element>"
    + "         startList>"
    + "         <ue_RadioAccessCapability>"
    + "            <accessStratumReleaseIndicator>r99accessStratumReleaseIndicator>"
    + "            <pdcp_Capability>"
    + "               <losslessSRNS_RelocationSupport>falselosslessSRNS_RelocationSupport>"
    + "               <supportForRfc2507>"
    + "                  <notSupported/>"
    + "               supportForRfc2507>"
    + "            pdcp_Capability>"
    + "            <rlc_Capability>"
    + "               <totalRLC_AM_BufferSize>kb150totalRLC_AM_BufferSize>"
    + "               <maximumRLC_WindowSize>mws2047maximumRLC_WindowSize>"
    + "               <maximumAM_EntityNumber>am6maximumAM_EntityNumber>"
    + "            rlc_Capability>"
    + "            <transportChannelCapability>"
    + "               <dl_TransChCapability>"
    + "                  <maxNoBitsReceived>b6400maxNoBitsReceived>"
    + "                  <maxConvCodeBitsReceived>b6400maxConvCodeBitsReceived>"
    + "                  <turboDecodingSupport>"
    + "                     <supported>b6400supported>"
    + "                  turboDecodingSupport>"
    + "                  <maxSimultaneousTransChs>e8maxSimultaneousTransChs>"
    + "                  <maxSimultaneousCCTrCH_Count>1maxSimultaneousCCTrCH_Count>"
    + "                  <maxReceivedTransportBlocks>tb32maxReceivedTransportBlocks>"
    + "                  <maxNumberOfTFC>tfc128maxNumberOfTFC>"
    + "                  <maxNumberOfTF>tf64maxNumberOfTF>"
    + "               dl_TransChCapability>"
    + "               <ul_TransChCapability>"
    + "                  <maxNoBitsTransmitted>b6400maxNoBitsTransmitted>"
    + "                  <maxConvCodeBitsTransmitted>b6400maxConvCodeBitsTransmitted>"
    + "                  <turboEncodingSupport>"
    + "                     <supported>b6400supported>"
    + "                  turboEncodingSupport>"
    + "                  <maxSimultaneousTransChs>e8maxSimultaneousTransChs>"
    + "                  <modeSpecificInfo>"
    + "                     <fdd/>"
    + "                  modeSpecificInfo>"
    + "                  <maxTransmittedBlocks>tb32maxTransmittedBlocks>"
    + "                  <maxNumberOfTFC>tfc64maxNumberOfTFC>"
    + "                  <maxNumberOfTF>tf64maxNumberOfTF>"
    + "               ul_TransChCapability>"
    + "            transportChannelCapability>"
    + "            <rf_Capability>"
    + "               <fddRF_Capability>"
    + "                  <ue_PowerClass>3ue_PowerClass>"
    + "                  <txRxFrequencySeparation>mhz190txRxFrequencySeparation>"
    + "               fddRF_Capability>"
    + "            rf_Capability>"
    + "            <physicalChannelCapability>"
    + "               <fddPhysChCapability>"
    + "                  <downlinkPhysChCapability>"
    + "                     <maxNoDPCH_PDSCH_Codes>1maxNoDPCH_PDSCH_Codes>"
    + "                     <maxNoPhysChBitsReceived>b9600maxNoPhysChBitsReceived>"
    + "                     <supportForSF_512>falsesupportForSF_512>"
    + "                     <supportOfPDSCH>falsesupportOfPDSCH>"
    + "                     <simultaneousSCCPCH_DPCH_Reception>"
    + "                        <notSupported/>"
    + "                     simultaneousSCCPCH_DPCH_Reception>"
    + "                  downlinkPhysChCapability>"
    + "                  <uplinkPhysChCapability>"
    + "                     <maxNoDPDCH_BitsTransmitted>b9600maxNoDPDCH_BitsTransmitted>"
    + "                     <supportOfPCPCH>falsesupportOfPCPCH>"
    + "                  uplinkPhysChCapability>"
    + "               fddPhysChCapability>"
    + "            physicalChannelCapability>"
    + "            <ue_MultiModeRAT_Capability>"
    + "               <multiRAT_CapabilityList>"
    + "                  <supportOfGSM>falsesupportOfGSM>"
    + "                  <supportOfMulticarrier>falsesupportOfMulticarrier>"
    + "               multiRAT_CapabilityList>"
    + "               <multiModeCapability>fddmultiModeCapability>"
    + "            ue_MultiModeRAT_Capability>"
    + "            <securityCapability>"
    + "               <cipheringAlgorithmCap>uea1 uea0cipheringAlgorithmCap>"
    + "               <integrityProtectionAlgorithmCap>uia1integrityProtectionAlgorithmCap>"
    + "            securityCapability>"
    + "            <ue_positioning_Capability>"
    + "               <standaloneLocMethodsSupported>falsestandaloneLocMethodsSupported>"
    + "               <ue_BasedOTDOA_Supported>falseue_BasedOTDOA_Supported>"
    + "               <networkAssistedGPS_Supported>noNetworkAssistedGPSnetworkAssistedGPS_Supported>"
    + "               <supportForUE_GPS_TimingOfCellFrames>falsesupportForUE_GPS_TimingOfCellFrames>"
    + "               <supportForIPDL>falsesupportForIPDL>"
    + "            ue_positioning_Capability>"
    + "            <measurementCapability>"
    + "               <downlinkCompressedMode>"
    + "                  <fdd_Measurements>truefdd_Measurements>"
    + "               downlinkCompressedMode>"
    + "               <uplinkCompressedMode>"
    + "                  <fdd_Measurements>truefdd_Measurements>"
    + "               uplinkCompressedMode>"
    + "            measurementCapability>"
    + "         ue_RadioAccessCapability>"
    + "      rrcConnectionSetupComplete>"
    + "   message>"
    + "uL_DCCH_Message>";

每次delphi客户端得到的结果解析不了。后用tcptrace工具截获请求和webservice返回的结果，得出结果是:实际的xml文档被夹在CDATAT标记中间，并没有（<写为<,>为>,&为&）转义。这也是delphi获得的结果，delphi对获得的串类型没有作任何处理，所以无法解析，除非去掉首尾CDATAT部分。而java的客户端可以得到的结果（去掉了CDATAT标记），即不包含CDATAT部分。问题出现在各自的SOAP引擎(根据SOAP规范生成请求应答)或消息的解析上（解析以xml传过来的数据）。

 查了一下XML资料查到类似的一段：

若果XML文档中包含XML或HTML时，那么<和>和&分别写成<和>和&来转义；若包含的XML文档过长，把整个XML或HTML包在CDATA标记里，避免转义造成XML文档膨胀过大，尤其通过网络来传输的xml尤为重要。

再对照前面给出的2各XML文档，区别就是长度。若过长websphere就使用CDATA标记，若不太长则使用转义。到底多长才使用CDATA标记，没找到相关的说明。

但delphi却没有这么灵活，无法处理这种情况。我同事只好每次得到XML信息，先判断是否有CDATA标记，有就去头截尾。