Class 转换异常 JSF
Class Cast Exception JSF
目前我正在使用 JSF，我有一个 data-table，当搜索过滤器完成时将加载值，下一步我有一个导出按钮，将数据导出为 xls 格式。在这种情况下导出数据。
但是当没有完成搜索并且 data-table 为空且只有 headers 列时，请单击导出图标。我收到以下异常，这是堆栈跟踪和附加图像以供参考
Apr 21, 2017 4:37:24 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel
java.lang.ClassCastException: javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel
at org.primefaces.component.datatable.DataTable.clearLazyCache(DataTable.java:964)
at org.primefaces.component.export.Exporter.exportAll(Exporter.java:224)
at org.primefaces.component.export.ExcelExporter.export(ExcelExporter.java:59)
at org.primefaces.component.export.DataExporter.processAction(DataExporter.java:97)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:769)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:105)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.ppts.setting.SessionFilter.doFilter(SessionFilter.java:38)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
Apr 21, 2017 4:37:24 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/GEO_DM] threw exception [javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel] with root cause
java.lang.ClassCastException: javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel
at org.primefaces.component.datatable.DataTable.clearLazyCache(DataTable.java:964)
at org.primefaces.component.export.Exporter.exportAll(Exporter.java:224)
at org.primefaces.component.export.ExcelExporter.export(ExcelExporter.java:59)
at org.primefaces.component.export.DataExporter.processAction(DataExporter.java:97)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:769)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:105)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.ppts.setting.SessionFilter.doFilter(SessionFilter.java:38)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
这是我用过的JSF代码
<label>Export</label> <span class="info-box-title"> <h:panelGrid
columns="2" border="0" cellpadding="3" cellspacing="5">
<h:commandLink>
<img src="images/excel.png" class="img-responsive" />
<p:dataExporter type="xls" target="removetagtbl"
fileName="LeaverJoinerDataxls"
postProcessor="#{leaverJoinerTagReportBean.postProcessXLS}"/>
</h:commandLink>
<h:commandLink style="padding-right: 20px;">
<img src="images/csv.png" />
<p:dataExporter type="csv" target="removetagtbl"
fileName="LeaverJoinerDatacsv" />
</h:commandLink>
我已经使用 LazyDataModel 将所有数据添加到列表中
请多指教，有不对的地方还请指正
这是使用 LazyDataModel 准备列表的代码
public class LeaverJoinerReportLazyModel extends LazyDataModel<LeaverJoinerTagReportDTO> {
private static final long serialVersionUID = 1L;
private List<LeaverJoinerTagReportDTO> datasource;
public LeaverJoinerReportLazyModel(List<LeaverJoinerTagReportDTO> datasource) {
this.datasource = datasource;
}
@Override
public LeaverJoinerTagReportDTO getRowData(String rowKey) {
for (LeaverJoinerTagReportDTO leaverJoinerTagReportDTO : datasource) {
if (leaverJoinerTagReportDTO.getLineId().equals(rowKey))
return leaverJoinerTagReportDTO;
}
return null;
}
@Override
public Object getRowKey(LeaverJoinerTagReportDTO leaverJoinerTagReportDTO) {
return leaverJoinerTagReportDTO.getLineId();
}
@Override
public List<LeaverJoinerTagReportDTO> load(int first, int pageSize,
String sortField, SortOrder sortOrder, Map<String, Object> filters) {
List<LeaverJoinerTagReportDTO> dataList = new ArrayList<LeaverJoinerTagReportDTO>();
// filter
for (LeaverJoinerTagReportDTO leaverJoinerTagReportDTO : datasource) {
boolean match = true;
if (filters != null) {
for (Iterator<String> iterator = filters.keySet().iterator();iterator.hasNext();) {
try {
String sFilterProperty = iterator.next();
Object sFilterValue = filters.get(sFilterProperty);
String sFieldValue = String.valueOf(leaverJoinerTagReportDTO.getClass().getField(sFilterProperty).get(leaverJoinerTagReportDTO));
if (sFilterValue == null || sFieldValue.startsWith(sFilterValue.toString())) {
match = true;
} else {
match = false;
break;
}
} catch (Exception e) {
match = false;
}
}
}else{
//Do Nothing
}
if (match) {
dataList.add(leaverJoinerTagReportDTO);
}
}
// rowCount
int dataSize = dataList.size();
this.setRowCount(dataSize);
// paginate
if (dataSize > pageSize) {
try {
return dataList.subList(first, first + pageSize);
} catch (IndexOutOfBoundsException e) {
return dataList.subList(first, first + (dataSize % pageSize));
}
} else {
return dataList;
}
}
}
我认为异常很明显，不是吗？你在某处使用 javax.faces.model.ListDataModel，Primefaces 试图在 clearLazyCache-Method 中将其转换为 org.primefaces.model.LazyDataModel。
LazyDataModel 可以转换为 DataModel（向上转换，总是可能的），因此如果运行时的实际类型是 [=15，您可以隐式转换它（向下转换） =]之前。
java.lang.Object
javax.faces.model.DataModel<T>
org.primefaces.model.LazyDataModel<T>
https://www.primefaces.org/docs/api/5.0/org/primefaces/model/LazyDataModel.html
但是 ListDataModel 是另一个树叶的一部分，因此此转换失败。
java.lang.Object
javax.faces.model.DataModel<E>
javax.faces.model.ListDataModel<E>
http://docs.oracle.com/javaee/6/api/javax/faces/model/ListDataModel.html
也许您应该添加您的 bean 代码，而不仅仅是页面的标记。
如果您在数据表上使用 lazy="true"，则必须使用 LazyDataModel 作为数据表中的值。如果您想使用普通 Java 列表，只需将其设置为 false。
目前我正在使用 JSF，我有一个 data-table，当搜索过滤器完成时将加载值，下一步我有一个导出按钮，将数据导出为 xls 格式。在这种情况下导出数据。
但是当没有完成搜索并且 data-table 为空且只有 headers 列时，请单击导出图标。我收到以下异常，这是堆栈跟踪和附加图像以供参考
Apr 21, 2017 4:37:24 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel
java.lang.ClassCastException: javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel
at org.primefaces.component.datatable.DataTable.clearLazyCache(DataTable.java:964)
at org.primefaces.component.export.Exporter.exportAll(Exporter.java:224)
at org.primefaces.component.export.ExcelExporter.export(ExcelExporter.java:59)
at org.primefaces.component.export.DataExporter.processAction(DataExporter.java:97)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:769)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:105)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.ppts.setting.SessionFilter.doFilter(SessionFilter.java:38)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
Apr 21, 2017 4:37:24 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/GEO_DM] threw exception [javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel] with root cause
java.lang.ClassCastException: javax.faces.model.ListDataModel cannot be cast to org.primefaces.model.LazyDataModel
at org.primefaces.component.datatable.DataTable.clearLazyCache(DataTable.java:964)
at org.primefaces.component.export.Exporter.exportAll(Exporter.java:224)
at org.primefaces.component.export.ExcelExporter.export(ExcelExporter.java:59)
at org.primefaces.component.export.DataExporter.processAction(DataExporter.java:97)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:769)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:409)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:105)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.ppts.setting.SessionFilter.doFilter(SessionFilter.java:38)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1527)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1484)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
这是我用过的JSF代码
<label>Export</label> <span class="info-box-title"> <h:panelGrid
columns="2" border="0" cellpadding="3" cellspacing="5">
<h:commandLink>
<img src="images/excel.png" class="img-responsive" />
<p:dataExporter type="xls" target="removetagtbl"
fileName="LeaverJoinerDataxls"
postProcessor="#{leaverJoinerTagReportBean.postProcessXLS}"/>
</h:commandLink>
<h:commandLink style="padding-right: 20px;">
<img src="images/csv.png" />
<p:dataExporter type="csv" target="removetagtbl"
fileName="LeaverJoinerDatacsv" />
</h:commandLink>
我已经使用 LazyDataModel 将所有数据添加到列表中
请多指教，有不对的地方还请指正
这是使用 LazyDataModel 准备列表的代码
public class LeaverJoinerReportLazyModel extends LazyDataModel<LeaverJoinerTagReportDTO> {
private static final long serialVersionUID = 1L;
private List<LeaverJoinerTagReportDTO> datasource;
public LeaverJoinerReportLazyModel(List<LeaverJoinerTagReportDTO> datasource) {
this.datasource = datasource;
}
@Override
public LeaverJoinerTagReportDTO getRowData(String rowKey) {
for (LeaverJoinerTagReportDTO leaverJoinerTagReportDTO : datasource) {
if (leaverJoinerTagReportDTO.getLineId().equals(rowKey))
return leaverJoinerTagReportDTO;
}
return null;
}
@Override
public Object getRowKey(LeaverJoinerTagReportDTO leaverJoinerTagReportDTO) {
return leaverJoinerTagReportDTO.getLineId();
}
@Override
public List<LeaverJoinerTagReportDTO> load(int first, int pageSize,
String sortField, SortOrder sortOrder, Map<String, Object> filters) {
List<LeaverJoinerTagReportDTO> dataList = new ArrayList<LeaverJoinerTagReportDTO>();
// filter
for (LeaverJoinerTagReportDTO leaverJoinerTagReportDTO : datasource) {
boolean match = true;
if (filters != null) {
for (Iterator<String> iterator = filters.keySet().iterator();iterator.hasNext();) {
try {
String sFilterProperty = iterator.next();
Object sFilterValue = filters.get(sFilterProperty);
String sFieldValue = String.valueOf(leaverJoinerTagReportDTO.getClass().getField(sFilterProperty).get(leaverJoinerTagReportDTO));
if (sFilterValue == null || sFieldValue.startsWith(sFilterValue.toString())) {
match = true;
} else {
match = false;
break;
}
} catch (Exception e) {
match = false;
}
}
}else{
//Do Nothing
}
if (match) {
dataList.add(leaverJoinerTagReportDTO);
}
}
// rowCount
int dataSize = dataList.size();
this.setRowCount(dataSize);
// paginate
if (dataSize > pageSize) {
try {
return dataList.subList(first, first + pageSize);
} catch (IndexOutOfBoundsException e) {
return dataList.subList(first, first + (dataSize % pageSize));
}
} else {
return dataList;
}
}
}
我认为异常很明显，不是吗？你在某处使用 javax.faces.model.ListDataModel，Primefaces 试图在 clearLazyCache-Method 中将其转换为 org.primefaces.model.LazyDataModel。
LazyDataModel 可以转换为 DataModel（向上转换，总是可能的），因此如果运行时的实际类型是 [=15，您可以隐式转换它（向下转换） =]之前。
java.lang.Object
javax.faces.model.DataModel<T>
org.primefaces.model.LazyDataModel<T>
https://www.primefaces.org/docs/api/5.0/org/primefaces/model/LazyDataModel.html
但是 ListDataModel 是另一个树叶的一部分，因此此转换失败。
java.lang.Object
javax.faces.model.DataModel<E>
javax.faces.model.ListDataModel<E>
http://docs.oracle.com/javaee/6/api/javax/faces/model/ListDataModel.html
也许您应该添加您的 bean 代码，而不仅仅是页面的标记。
如果您在数据表上使用 lazy="true"，则必须使用 LazyDataModel 作为数据表中的值。如果您想使用普通 Java 列表，只需将其设置为 false。