我有一个简单的查询
select t.firstname, t.lastname, t.zipcode, t.city
from name_data t where name_id = ?
这 '?' 是输入参数,永远不会为空。
该查询返回一条类似于以下内容之一的记录:
案例 1 - 个人
'First Name' 'Last Name' 'zipcode' 'city'
-------------------------------------------------------
John Doe 1177 Somewhere
案例 2 - 公司
'First Name' 'Last Name' 'zipcode' 'city'
-----------------------------------------------------------
<<null>> ACME Ltd 1199 'Somewhere else'
当我获得第二条记录时,DSS 会抛出 NullPointerException。
我猜这是因为 Firstname 中的 <> 值,我找到了一种通过测试 SQL (Oracle) 中的空值来绕过它的方法
“选择 nvl(t.firstname, ' ') firstname, nvl(t.lastname, ' '), lastname, nvl(t.zipcode, ' '), nvl(t.city, ' ') 等...”
这适用于所有可以为空的列(我的查询比这长一点),因为它们是可选的。
我知道如果数据库设计正确(例如创建两个不同的实体来管理人员和公司),这不应该发生(理论上),但它是一个商业产品,然后我无法更改它,我用一个简单的案例来解释一个很长的查询。
我的 .dbs 的摘录是:
<?xml version="1.0" encoding="UTF-8"?>
<data xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="http:///org/wso2/carbonstudio/eclipse/ds"
name="${groupId}.${artifactId}-customeraddress-1"
serviceNamespace="urn:customeraddress.database.mycompany.org/1"
serviceGroup="${groupId}" baseURI="">
<description>This is the datasource to access the customer address information</description>
<config id="ambocs">
<property name="org.wso2.ws.dataservice.driver">@ambocs.driver@</property>
<property name="org.wso2.ws.dataservice.protocol">@ambocs.url@</property>
<property name="org.wso2.ws.dataservice.user">@ambocs.user@</property>
<property name="org.wso2.ws.dataservice.password">@ambocs.password@</property>
<property name="org.wso2.ws.dataservice.minpoolsize">@ambocs.minpoolsize@</property>
<property name="org.wso2.ws.dataservice.maxpoolsize">@ambocs.maxpoolsize@</property>
<property name="org.wso2.ws.dataservice.validation_query">select 1 from dual</property>
</config>
<query id="getCustomerAddressByIdRef" useConfig="ambocs" returnRowId="true">
<sql>
select
nvl(nd.first_name, ' ') first_name,
nvl(nd.last_name, ' ') last_name,
nvl(nd.adr_zip, ' ') zipcode,
nvl(nd.adr_city, ' ') city,
nvl(nd.adr_country, ' ') country
from name_data nd
where nd.name_id = ?
</sql>
<properties>
<property name="org.wso2.ws.dataservice.query_timeout"></property>
<property name="org.wso2.ws.dataservice.fetch_direction"></property>
<property name="org.wso2.ws.dataservice.fetch_size"></property>
<property name="org.wso2.ws.dataservice.max_field_size"></property>
<property name="org.wso2.ws.dataservice.max_rows"></property>
</properties>
<result element="ContactDetails" rowName="ContactDetail"
defaultNamespace="urn:customeraddress.database.mycompany.org/1" outputType="xml">
<attribute name="firstName" column="first_name" query-param="" requiredRoles="" xsdType="xs:string"/>
<attribute name="lastName" column="last_business_name" query-param="" requiredRoles="" xsdType="xs:string"/>
<attribute name="locality" column="city" query-param="" requiredRoles="" xsdType="xs:string"/>
<attribute name="postcode" column="zipcode" query-param="" requiredRoles="" xsdType="xs:string"/>
<attribute name="country" column="country" query-param="" requiredRoles="" xsdType="xs:string"/>
</result>
<param name="nameId" type="IN" sqlType="STRING" defaultValue="" />
</query>
<operation name="getCustomerAddressById">
<call-query href="getCustomerAddressByIdRef">
<with-param name="nameId" column="nameId" query-param="nameId"/>
</call-query>
</operation>
</data>
您是否知道是否可以选择放入 .dbs 以管理查询返回的空值?
我试图在 wso2.org 上找到一个文档,但它是非常简单的示例,与此案例无关。
更新 这里的表模式:
CREATE TABLE "NAME_DATA"
(
"NAME_ID" NUMBER(9,0) CONSTRAINT "PK_NAME_ID" NOT NULL ENABLE,
"SYS_CREATION_DATE" DATE NOT NULL ENABLE,
"SYS_UPDATE_DATE" DATE,
"LAST_NAME" VARCHAR2(60),
"FIRST_NAME" VARCHAR2(32),
"ZIP_CODE" VARCHAR2(4),
"CITY" VARCHAR2(255),
"COUNTRY" CHAR(3 BYTE),
CONSTRAINT "NAME_DATA_PK" PRIMARY KEY ("NAME_ID")
)
CREATE UNIQUE INDEX "NAME_DATA_PK" ON "NAME_DATA" ("NAME_ID")
CREATE INDEX "IDX_NAME_DATA_1" ON "NAME_DATA"("LAST_NAME","FIRST_NAME")
CREATE INDEX "IDX_NAME_DATA_2" ON "NAME_DATA"(UPPER("FIRST_NAME"))
CREATE INDEX "IDX_NAME_DATA_3" ON "NAME_DATA"(UPPER("LAST_NAME"))
更新 2 - 堆栈跟踪:
TID: [0] [WSO2 Data Services Server] [2012-03-27 14:02:22,730] ERROR {org.apache.axis2.transport.http.AxisServlet} - {org.apache.axis2.transport.http.AxisServlet}
java.lang.NullPointerException
at com.ctc.wstx.sw.BaseNsStreamWriter.doWriteAttr(BaseNsStreamWriter.java:468)
at com.ctc.wstx.sw.BaseNsStreamWriter.writeAttribute(BaseNsStreamWriter.java:230)
at org.apache.axiom.util.stax.wrapper.XMLStreamWriterWrapper.writeAttribute(XMLStreamWriterWrapper.java:88)
at org.apache.axiom.om.impl.MTOMXMLStreamWriter.writeAttribute(MTOMXMLStreamWriter.java:230)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.writeXMLEvent(DSWrappedXMLStreamWriter.java:418)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.writeOutInitialXMLEvents(DSWrappedXMLStreamWriter.java:508)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.finalizeBuffering(DSWrappedXMLStreamWriter.java:501)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.flush(DSWrappedXMLStreamWriter.java:145)
at org.wso2.carbon.dataservices.core.engine.DSOMDataSource.execute(DSOMDataSource.java:102)
at org.wso2.carbon.dataservices.core.engine.DSOMDataSource.serialize(DSOMDataSource.java:110)
at org.apache.axiom.om.impl.llom.OMSourcedElementImpl.internalSerialize(OMSourcedElementImpl.java:691)
at org.apache.axiom.om.impl.util.OMSerializerUtil.serializeChildren(OMSerializerUtil.java:563)
at org.apache.axiom.om.impl.llom.OMElementImpl.internalSerialize(OMElementImpl.java:875)
at org.apache.axiom.soap.impl.llom.SOAPEnvelopeImpl.serializeInternally(SOAPEnvelopeImpl.java:283)
at org.apache.axiom.soap.impl.llom.SOAPEnvelopeImpl.internalSerialize(SOAPEnvelopeImpl.java:245)
at org.apache.axiom.om.impl.llom.OMSerializableImpl.serializeAndConsume(OMSerializableImpl.java:193)
at org.apache.axis2.transport.http.SOAPMessageFormatter.writeTo(SOAPMessageFormatter.java:74)
at org.apache.axis2.transport.http.CommonsHTTPTransportSender.sendUsingOutputStream(CommonsHTTPTransportSender.java:409)
at org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:286)
at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:443)
at org.apache.axis2.receivers.AbstractInOutSyncMessageReceiver.invokeBusinessLogic(AbstractInOutSyncMessageReceiver.java:45)
at org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:110)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:181)
at org.apache.axis2.transport.http.HTTPTransportUtils.processHTTPPostRequest(HTTPTransportUtils.java:172)
at org.apache.axis2.transport.http.AxisServlet.doPost(AxisServlet.java:146)
at org.wso2.carbon.core.transports.CarbonServlet.doPost(CarbonServlet.java:199)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.handleRequest(ServletRegistration.java:90)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:111)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:67)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.wso2.carbon.bridge.BridgeServlet.service(BridgeServlet.java:164)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.wso2.carbon.server.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:154)
at org.wso2.carbon.server.TomcatServer$1.invoke(TomcatServer.java:254)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399)
at org.apache.coyote.http11.Http11NioProcessor.process(Http11NioProcessor.java:396)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:356)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1534)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
TID: [0] [WSO2 Data Services Server] [2012-03-27 14:02:22,730] ERROR {org.apache.axis2.transport.http.AxisServlet} - {org.apache.axis2.transport.http.AxisServlet}
java.lang.NullPointerException
at com.ctc.wstx.sw.BaseNsStreamWriter.doWriteAttr(BaseNsStreamWriter.java:468)
at com.ctc.wstx.sw.BaseNsStreamWriter.writeAttribute(BaseNsStreamWriter.java:230)
at org.apache.axiom.util.stax.wrapper.XMLStreamWriterWrapper.writeAttribute(XMLStreamWriterWrapper.java:88)
at org.apache.axiom.om.impl.MTOMXMLStreamWriter.writeAttribute(MTOMXMLStreamWriter.java:230)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.writeXMLEvent(DSWrappedXMLStreamWriter.java:418)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.writeOutInitialXMLEvents(DSWrappedXMLStreamWriter.java:508)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.finalizeBuffering(DSWrappedXMLStreamWriter.java:501)
at org.wso2.carbon.dataservices.core.engine.DSWrappedXMLStreamWriter.flush(DSWrappedXMLStreamWriter.java:145)
at org.wso2.carbon.dataservices.core.engine.DSOMDataSource.execute(DSOMDataSource.java:102)
at org.wso2.carbon.dataservices.core.engine.DSOMDataSource.serialize(DSOMDataSource.java:110)
at org.apache.axiom.om.impl.llom.OMSourcedElementImpl.internalSerialize(OMSourcedElementImpl.java:691)
at org.apache.axiom.om.impl.util.OMSerializerUtil.serializeChildren(OMSerializerUtil.java:563)
at org.apache.axiom.om.impl.llom.OMElementImpl.internalSerialize(OMElementImpl.java:875)
at org.apache.axiom.soap.impl.llom.SOAPEnvelopeImpl.serializeInternally(SOAPEnvelopeImpl.java:283)
at org.apache.axiom.soap.impl.llom.SOAPEnvelopeImpl.internalSerialize(SOAPEnvelopeImpl.java:245)
at org.apache.axiom.om.impl.llom.OMSerializableImpl.serializeAndConsume(OMSerializableImpl.java:193)
at org.apache.axis2.transport.http.SOAPMessageFormatter.writeTo(SOAPMessageFormatter.java:74)
at org.apache.axis2.transport.http.CommonsHTTPTransportSender.sendUsingOutputStream(CommonsHTTPTransportSender.java:409)
at org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:286)
at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:443)
at org.apache.axis2.receivers.AbstractInOutSyncMessageReceiver.invokeBusinessLogic(AbstractInOutSyncMessageReceiver.java:45)
at org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:110)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:181)
at org.apache.axis2.transport.http.HTTPTransportUtils.processHTTPPostRequest(HTTPTransportUtils.java:172)
at org.apache.axis2.transport.http.AxisServlet.doPost(AxisServlet.java:146)
at org.wso2.carbon.core.transports.CarbonServlet.doPost(CarbonServlet.java:199)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.handleRequest(ServletRegistration.java:90)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:111)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:67)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.wso2.carbon.bridge.BridgeServlet.service(BridgeServlet.java:164)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.wso2.carbon.server.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:154)
at org.wso2.carbon.server.TomcatServer$1.invoke(TomcatServer.java:254)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399)
at org.apache.coyote.http11.Http11NioProcessor.process(Http11NioProcessor.java:396)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:356)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1534)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
为了对此进行测试,您必须删除 DBS 中的所有“nvl(...)”,否则它运行良好。这是 first_name 为“null”的记录。