我尝试使用documentbuilder将xml结果转换为字符串。我构建了以下函数，以便从数据库中获取所有结果，当我将它们存储在列表中并将它们发送到列表时一切都很好，但是当我尝试将结果显示为字符串xml时，下一个错误就会出现起来。
WS00041: Service invocation threw an exception with message : null; Refer to the server log for more details
Exceptions details : java.lang.reflect.InvocationTargetException
javax.servlet.ServletException: java.lang.reflect.InvocationTargetException
at org.glassfish.webservices.monitoring.WebServiceTesterServlet.doPost(WebServiceTesterServlet.java:342)
at org.glassfish.webservices.monitoring.WebServiceTesterServlet.invoke(WebServiceTesterServlet.java:106)
at org.glassfish.webservices.JAXWSServlet.doPost(JAXWSServlet.java:157)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:415)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:282)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:201)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:175)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:561)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.glassfish.webservices.monitoring.WebServiceTesterServlet.doPost(WebServiceTesterServlet.java:313) ... 32 more
Caused by: com.sun.xml.ws.fault.ServerSOAPFaultException: Client received SOAP Fault from server: java.lang.IllegalArgumentException: Can not set java.util.List field NewWebServiceMaterias.jaxws.GetMateriaResponse._return to java.lang.String Please see the server log to find more detail regarding exact cause of the failure.
at com.sun.xml.ws.fault.SOAP11Fault.getProtocolException(SOAP11Fault.java:193)
at com.sun.xml.ws.fault.SOAPFaultBuilder.createException(SOAPFaultBuilder.java:131)
at com.sun.xml.ws.client.sei.StubHandler.readResponse(StubHandler.java:253)
at com.sun.xml.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:203)
at com.sun.xml.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:290)
at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:119)
at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:92)
at com.sun.xml.ws.client.sei.SEIStub.invoke(SEIStub.java:161)
at com.sun.proxy.$Proxy283.getMateria(Unknown Source) ... 37 more
代码：
@WebMethod(operationName = "getMateria")
public String getMateria() {
Conexion c = new Conexion();
Connection cn = c.Conectar();
List<Materia> materia;
String mensaje;
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder;
try {
docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("materia");
doc.appendChild(rootElement);
try {
Statement st = cn.createStatement();
ResultSet rs = st.executeQuery("select * from asignaturas");
materia = new ArrayList<>();
while (rs.next()) {
materia.add(new Materia(rs.getInt(1), rs.getString(2), rs.getString(3), rs.getString(4)));
Element nombreMateria = doc.createElement("nombre");
nombreMateria.appendChild(doc.createTextNode(rs.getString(3)));
Element detMateria = doc.createElement("detalle");
detMateria.appendChild(doc.createTextNode(rs.getString(4)));
rootElement.appendChild(nombreMateria);
rootElement.appendChild(detMateria);
}
TransformerFactory tf = TransformerFactory.newInstance();
Transformer transformer = tf.newTransformer();
//transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
StringWriter writer = new StringWriter();
transformer.transform(new DOMSource(doc), new StreamResult(writer));
String output = writer.getBuffer().toString().replaceAll("\n|\r", "");
return output;
} catch (SQLException | DOMException | TransformerException e) {
mensaje = "este es un error" + e.getMessage();
}
} catch (ParserConfigurationException ex) {
Logger.getLogger(NewWebServiceMaterias.class.getName()).log(Level.SEVERE, null, ex);
mensaje = "ESTAMOS EN EL ERROR 1" + ex.getMessage();
}
return mensaje + "El valor no se ha encontrado";
}
答案 0 :(得分：0)
可能的原因之一：从右到左的顺序检索列值，然后检索一次：
while (rs.next()) {
materia.add(new Materia(rs.getInt(1),
rs.getString(2), rs.getString(3), rs.getString(4)));
// skipped
nombreMateria.appendChild(doc.createTextNode(rs.getString(3)));
detMateria.appendChild(doc.createTextNode(rs.getString(4)));
// skipped
}
这可能导致您期望（在Materia构造函数中或在您调用apendChild(...)时）与获得的内容之间不匹配（调用getString(...)可以返回NULL ）。
如documentation中所述：
默认
ResultSet对象不可更新且具有光标 只向前迈进。因此，您只需迭代一次即可 仅从第一行到最后一行。为了获得最大的可移植性，每行中的结果集列应该是 按从左到右的顺序读取，每列应只读一次。