我在 PrimeFaces 数据表中有问题，
在页面 xhtml，我有两个用于 SQL 和函数的单选按钮，然后我有一个输入文本来选择我想要调用的函数，例如“从 t_tenant 中选择 *”
这是页面 xhtml 的代码：
<p:panel>
<p:commandButton value="#{piece['org.jlego.commonui.run']}" actionListener="#{dbQueryController.run}" ajax="true" update="queryEditor grid growl exportButton panelMessage" />
<p:commandButton value="#{piece['org.jlego.commonui.clear']}" update="queryEditor panelMessage grid growl exportButton" actionListener="#{dbQueryController.clear}"/>
<br/>
<h:panelGrid columns="2">
<h:outputText value="#{piece['org.jlego.commonui.type']}" />
<h:selectOneRadio id="queryType" value="#{dbQueryController.type}">
<f:selectItem itemValue="#{piece['org.jlego.commonui.sql']}" itemLabel="#{piece['org.jlego.commonui.sql']}" />
<f:selectItem itemValue="#{piece['org.jlego.commonui.function']}" itemLabel="#{piece['org.jlego.commonui.function']}" />
</h:selectOneRadio>
</h:panelGrid>
<p:inputTextarea id="queryEditor" style="width: 800px; height: 200px; font-family: Courier"
value="#{dbQueryController.query}" />
<p:panel id="panelMessage">
<h:outputText value="#{dbQueryController.message}" />
</p:panel>
<br/>
<...><...>
<p:dataTable id="grid" value="#{dbQueryController.queryList}" var="item"
scrollable="true" scrollWidth="1000" scrollHeight="300" resizableColumns="true">
<p:columns value="#{dbQueryController.columns}" var="column" columnIndexVar="colIndex">
<f:facet name="header">
#{column.header}
</f:facet>
#{item[column.property]}
</p:columns>
</p:dataTable>
</p:panel>
这是控制器的代码：
@Component
@Scope("view")
public class DbQueryController extends AbstractController {
private static final Logger log = LoggerFactory.getLogger(DbQueryController.class);
@Autowired
private ServiceContext serviceContext;
private String type;
private String query;
private String message;
private List<JSONObject> queryList;
private String columnTemplate = "";
private List<ColumnModel> columns;
public DbQueryController() {
type = "SQL"; // Default value
queryList = new ArrayList<JSONObject>();
columns = new ArrayList<ColumnModel>();
}
@PostConstruct
private void init() {
}
/**
* When "Run" button clicked
*/
public String run() {
log.debug("run() called");
// Validate Query Must Be Filled
if (query == null || query.equals("")){
FacesUtils.addErrorMessage(getLabel("org.jlego.commonui.noStatementQueryFound"));
return "";
}
queryList = new ArrayList<JSONObject>();
message = "";
JSONObject input = new JSONObject();
input.put("type", type);
input.put("query", query);
try {
JSONObject output = serviceContext.executeService("jlego#getResultQuery", input);
JSONObject result = JSONObjectUtil.getResult(output);
String status = JSONObjectUtil.getResultStatus(output);
if (status != null && status.equals(GeneralConstants.OK)) {
queryList = (List<JSONObject>) JSONObjectUtil.convertToArray(result.get("queryList"));
if (queryList == null) {
queryList = new ArrayList<JSONObject>();
}
message = queryList.size() + " data found";
if (result.get("columns") instanceof JSONArray) {
JSONArray arr = (JSONArray) result.get("columns");
columnTemplate = "";
StringBuilder build = new StringBuilder();
for (int i = 0; i < arr.size(); i++) {
build.append(arr.get(i)).append(" ");
}
columnTemplate = build.toString();
} else if (result.get("columns") instanceof String) {
String str = (String) result.get("columns");
columnTemplate = str;
}
createDynamicColumns();
} else if (status != null && status.equals(GeneralConstants.FAIL))
{
FacesUtils.addErrorMessage((String) result.get("message"));
}
} catch (Exception e) {
e.printStackTrace();
FacesUtils.addErrorMessage(e.getMessage());
}
return "";
}
/**
* When "Clear" button clicked
*/
public void clear() {
setQuery("");
queryList = null;
columnTemplate = "";
columns.clear();
message = "";
}
<....>
/**
* @return the queryList
*/
public List<JSONObject> getQueryList() {
return queryList;
}
/**
* @return the columnTemplate
*/
public String getColumnTemplate() {
return columnTemplate;
}
public List<ColumnModel> getColumns() {
return columns;
}
static public class ColumnModel implements Serializable {
private String header;
private String property;
public ColumnModel(String header, String property) {
this.header = header;
this.property = property;
}
<...>
private void updateColumns() {
// reset table state
UIComponent table = FacesContext.getCurrentInstance().getViewRoot().findComponent(":rootform:grid");
table.setValueExpression("sortBy", null);
// update columns
createDynamicColumns();
}
public void createDynamicColumns() {
log.debug(columnTemplate);
String[] columnKeys = columnTemplate.split(" ");
columns.clear();
for (String columnKey : columnKeys) {
String key = columnKey.trim();
columns.add(new ColumnModel(columnKey, columnKey));
}
}
问题是，当我填写输入文本查询以选择诸如“select * from t_tenant”之类的函数 SQL 并单击“运行”按钮时，已显示数据表，但表的网格无法显示数据库中的全部数据，我得到了异常.
这是我得到的异常消息：
Jul 6, 2012 9:13:14 AM com.sun.faces.context.PartialViewContextImpl processPartial
INFO: java.lang.NullPointerException
java.lang.NullPointerException
at org.primefaces.component.datatable.DataTable.syncColumnWidths(DataTable.java:1031)
at org.primefaces.component.datatable.DataTableRenderer.decode(DataTableRenderer.java:60)
at javax.faces.component.UIComponentBase.decode(UIComponentBase.java:787)
at javax.faces.component.UIData.processDecodes(UIData.java:1162)
at org.primefaces.component.datatable.DataTable.processDecodes(DataTable.java:554)
at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:506)
at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
at javax.faces.component.UIData.visitTree(UIData.java:1411)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1601)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1601)
at javax.faces.component.UIForm.visitTree(UIForm.java:344)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1601)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1601)
at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:376)
at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:252)
at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
at javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:931)
at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:78)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1221)
at org.jlego.web.WebLoginSessionFilter.doFilter(WebLoginSessionFilter.java:95)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:399)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:945)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
如果我使用的是 primefaces 3.3.1
谢谢你的帮助
问候