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私は、DynamoDBテーブル（AmazonのNoSQL DB）から取得しているデータでJSF Datatableを作成しようとしています。現時点では、scanResultsに対する反復まですべてが正常に機能しています。デバッガは、私のscanResultがすべてのアカウントのリストを持っていることを示していますが、リストを構築するためにこれらの結果を繰り返し処理しようとすると、allUserSummaryリストに何も追加されていないように見え、nullpointer例外が発生します。DynamoDBからDatatableを取り込みます
基本的なユーザーPOJO：
public class User {
private String uuid;
public User(String uuid) {
this.uuid = uuid;
}
}
管理Bean：
private List<User> allUserSummary;
private List<String> uuid;
private User selectedUser;
public List<User> getAllUserSummary() throws Exception {
populateData();
return allUserSummary;
}
private void populateData() throws Exception {
// Create a new AmazonDynamoDBClient and mapper
AmazonDynamoDBClient client = dynamoClient.getDynamoClient();
DynamoDBMapper mapper = new DynamoDBMapper(client);
try {
// Create a new scan expression and filter to find the required data from the db
DynamoDBScanExpression scanExpression = new DynamoDBScanExpression();
Map<String, Condition> scanFilter = new HashMap<String, Condition>();
Condition scanCondition = new Condition().withComparisonOperator(ComparisonOperator.NOT_NULL);
scanFilter.put("uuid", scanCondition);
scanExpression.setScanFilter(scanFilter);
// Run the scan
List scanResults = mapper.scan(UserAccounts.class, scanExpression);
// Iterate over the scanned results and add the required data to a new User
for (Iterator it = scanResults.iterator(); it.hasNext();) {
allUserSummary.add(new User(scanResults.get(1).toString()));
}
} catch (Exception e) {
// TODO
}
}
DATATABLE（primefacesを使用してイムが、問題は、標準JSF DTと同じです）：
<h:form>
<pou:dataTable id="users"
var="user"
value="#{accountManager.allUserSummary}"
paginator="true"
rows="10"
selection="#{accountManager.selectedUser}">
<f:facet name="header">
UUID
</f:facet>
<pou:column selectionMode="multiple" />
<pou:column headerText="Uuid">
#{user.uuid}
</pou:column>
<f:facet name="footer">
<pou:commandButton id="multiViewButton"
value="View"
icon="ui-icon-search"
update=""
oncomplete=""/>
</f:facet>
</pou:dataTable>
</h:form>
スタックトレース：
java.lang.IllegalArgumentException: ""
at javax.faces.component.UIComponentBase.findComponent(UIComponentBase.java:570)
at org.primefaces.util.ComponentUtils.findClientIds(ComponentUtils.java:244)
at org.primefaces.renderkit.CoreRenderer.buildAjaxRequest(CoreRenderer.java:222)
at org.primefaces.component.commandbutton.CommandButtonRenderer.encodeMarkup(CommandButtonRenderer.java:81)
at org.primefaces.component.commandbutton.CommandButtonRenderer.encodeEnd(CommandButtonRenderer.java:53)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1764)
at org.primefaces.component.datatable.DataTableRenderer.encodeFacet(DataTableRenderer.java:839)
at org.primefaces.component.datatable.DataTableRenderer.encodeTFoot(DataTableRenderer.java:823)
at org.primefaces.component.datatable.DataTableRenderer.encodeRegularTable(DataTableRenderer.java:247)
at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:224)
at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:108)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1764)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1757)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:288)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1542)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:380)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:680)
allUserSummaryリストを初期化しましたか？このプライベートリストのように allUserSummary = new ArrayList （）; –
Daniel
@Danielはい、私はまた、init（）の内容をgetAllUserSummary（）に移しました。私は実際にその段階でnullポインタを取得しません。エラーです：java.lang.IllegalArgumentException： ""！ – tarka
あなたのコードのどの行がスタック例外をスローされたのかというよりも、完全なスタックトレースを投稿します。 – Daniel