当我点击Speak Out（p：commandButton）提交状态时，我收到以下异常。该异常是由行
的commentList（）函数引起的Query query = em.createQuery(
"SELECT c FROM Comment c WHERE c.statusId=" + statusId,
Comment.class);
1）Home.xhtml
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui"
xmlns:c="http://java.sun.com/jsp/jstl/core">
<h:head>
</h:head>
<div style="width: 100%; background-color: #EEEEEE;">
<h:panelGrid columns="1">
<h:form id="speakout">
<h:outputText value="Speak Out" />
<br />
<h:outputText value="Share whats in your mind.!"
style="color:#aaaaaa;font-size:x-small;" />
<p:inputTextarea name="content" id="sharetext" cols="60" rows="2"
onclick="this.value='';" value="#{statusBean.status.statusmsg}"
style="text-size:small;" />
<br />
<p:commandButton type="submit" value="Speak Out"
action="#{statusBean.save}" ajax="false"
styleClass="buttonstyle" />
<br />
</h:form>
</div>
<!-- -->
<div class="items">
<h:form>
<ui:repeat var="p" value="#{statusBean.statusList}">
<ui:fragment rendered="#{p.statusmsg!=null}">
<div class="status">
<!-- for text status msg check-->
<h:commandLink action="#{friendBean.gotoFriendProfile(p.email)}"
styleClass="link">
<img src="../images/profilePicture/thumb/#{p.picture}"
style="height: 39px; width: 39px;" />
<h:outputText value="#{p.statusBy}:" />
</h:commandLink>
<h:outputText value="#{p.statusmsg}" styleClass="textstyle1" />
<h:outputText value="#{p.timeMillis}"
style="font-size:xx-small;float:right;color:#bbbbbb;font-style: italic;">
<f:converter converterId="timeConverter" />
</h:outputText>
<h:commandLink action="#{statusBean.deleteStatus(p.statusId)}"
value="Delete"></h:commandLink>
<p:growl />
<br />
<ui:repeat var="q" value="#{statusBean.commentList(p.statusId)}" >
<div class="barcomment">
<br />
<h:commandLink action="#{friendBean.gotoFriendProfile(q.email)}"
styleClass="link">
<img src="../images/profilePicture/thumb/#{q.picture}"
style="height: 29px; width: 29px;" />
<h:outputText value="#{q.commentBy}:" />
</h:commandLink>
<h:outputText value=" #{q.comment}" styleClass="textstyle1" />
<h:outputText value="#{q.timeMillis}"
style="font-size:xx-small;float:right;font-style: italic;">
<f:converter converterId="timeConverter" />
</h:outputText>
<h:commandLink action="#{statusBean.deleteComment(q.commentId)}"
value="Delete"></h:commandLink>
</div>
</ui:repeat>
<br />
<div class="comment">
<p:inputText value="#{statusBean.comment.comment}"
styleClass="box" />
<p:commandLink value="Views"
action="#{statusBean.update(p.statusId)}"
ajax="false" styleClass="link" />
</div>
<br />
</div>
</ui:fragment>
</ui:repeat>
</h:form>
</div>
</h:body>
</html>
2）状态Bean
package com.bean;
public class StatusBean {
Date d;
Comment comment;
Status status;
private EntityManager em;
private UploadedFile uploadedFile;
public Comment getComment() {
return comment;
}
public void setComment(Comment comment) {
this.comment = comment;
}
public Status getStatus() {
return status;
}
public void setStatus(Status status) {
this.status = status;
}
public StatusBean() {
d = new Date();
comment = new Comment();
status = new Status();
EntityManagerFactory emf = Persistence
.createEntityManagerFactory("FreeBird");
em = emf.createEntityManager();
}
public List<Status> getStatusList() {
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(true);
User user = (User) session.getAttribute("userdet");
Query query = em.createQuery("SELECT s FROM Status s WHERE s.email='"
+ user.getEmail() + "' ORDER BY s.timeMillis desc",
Status.class);
List<Status> results = query.getResultList();
Query query1 = em.createQuery("SELECT f FROM Friend f WHERE f.email='"
+ user.getEmail() + "'", Friend.class);
List<Friend> results1 = query1.getResultList();
Iterator<Friend> it = results1.listIterator();
while (it.hasNext()) {
String email = it.next().getFriendEmail();
Query query2 = em.createQuery(
"SELECT s FROM Status s WHERE s.email='" + email
+ "' ORDER BY s.timeMillis desc", Status.class);
List<Status> results2 = query2.getResultList();
results.addAll(results2);
}
Collections.sort(results);
int index = 0;
int end = index+5 > results.size() ? results.size() : index+5;
List<Status> subList = results.subList(0, end);
session.setAttribute("statusindex", end);
return subList;
}
public String save() {
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(false);
User user = (User) session.getAttribute("userdet");
status.setEmail(user.getEmail());
status.setStatusBy(user.getFirstName());
d = new Date();
status.setTimeMillis(d.getTime());
status.setPicture(user.getImage());
System.out.println("status save called");
em.getTransaction().begin();
em.persist(status);
em.getTransaction().commit();
FacesContext context2 = FacesContext.getCurrentInstance();
context2.getExternalContext().getSessionMap().remove("statusBean");
return "success";
}
public String update(String statusId) {
System.out.println("Update Called...");
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(true);
User user = (User) session.getAttribute("userdet");
comment.setStatusId(Integer.parseInt(statusId));
comment.setCommentBy(user.getFirstName());
comment.setPicture(user.getImage());
comment.setEmail(user.getEmail());
d = new Date();
comment.setTimeMillis(d.getTime());
em.getTransaction().begin();
em.persist(comment);
em.getTransaction().commit();
getComment().setComment("");
FacesContext context2 = FacesContext.getCurrentInstance();
context2.getExternalContext().getSessionMap().remove("statusBean");
return "success";
}
public List<Comment> commentList(String statusId) {
FacesContext context = FacesContext.getCurrentInstance();
Query query = em.createQuery(
"SELECT c FROM Comment c WHERE c.statusId=" + statusId,
Comment.class);
List<Comment> results = query.getResultList();
return results;
}
public String deleteStatus(String statusId) {
Status status = em.find(Status.class, Integer.parseInt(statusId));
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(true);
User user = (User) session.getAttribute("userdet");
if (user.getEmail().equals(status.getEmail())) {
em.getTransaction().begin();
em.remove(status);
em.getTransaction().commit();
} else {
context.addMessage(null, new FacesMessage(
"You don't have permission to delete"));
}
return "success";
}
public String deleteComment(String commentId) {
Comment comment = em.find(Comment.class, Integer.parseInt(commentId));
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) context.getExternalContext()
.getSession(true);
User user = (User) session.getAttribute("userdet");
Status status = em.find(Status.class, comment.getStatusId());
if (user.getEmail().equals(status.getEmail())
|| comment.getEmail().equals(user.getEmail()))
{
em.getTransaction().begin();
em.remove(comment);
em.getTransaction().commit();
} else {
context.addMessage(null, new FacesMessage(
"You don't have permission to delete"));
}
return "success";
}
}
3）异常
Mar 03, 2013 9:10:26 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/FreeBird_v.6] threw exception [An exception occurred while creating a query in EntityManager:
Exception Description: Syntax error parsing the query [SELECT c FROM Comment c WHERE c.statusId=], line 0, column -1: unexpected end of query.
Internal Exception: NoViableAltException(-1@[792:1: comparisonExpressionRightOperand returns [Object node] : (n= arithmeticExpression | n= nonArithmeticScalarExpression | n= anyOrAllExpression );])] with root cause
NoViableAltException(-1@[792:1: comparisonExpressionRightOperand returns [Object node] : (n= arithmeticExpression | n= nonArithmeticScalarExpression | n= anyOrAllExpression );])
at org.eclipse.persistence.internal.libraries.antlr.runtime.DFA.noViableAlt(DFA.java:159)
at org.eclipse.persistence.internal.libraries.antlr.runtime.DFA.predict(DFA.java:144)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.comparisonExpressionRightOperand(JPQLParser.java:4326)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.comparisonExpression(JPQLParser.java:4215)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.simpleConditionalExpressionRemainder(JPQLParser.java:3389)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.simpleConditionalExpression(JPQLParser.java:3326)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.conditionalPrimary(JPQLParser.java:3275)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.conditionalFactor(JPQLParser.java:3194)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.conditionalTerm(JPQLParser.java:3103)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.conditionalExpression(JPQLParser.java:3029)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.whereClause(JPQLParser.java:2986)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.selectStatement(JPQLParser.java:380)
at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.document(JPQLParser.java:281)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.parse(JPQLParser.java:134)
at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.buildParseTree(JPQLParser.java:95)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:215)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:190)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:142)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:126)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1475)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1497)
at com.bean.StatusBean.commentList(StatusBean.java:227)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:484)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:161)
at org.apache.el.parser.AstValue.getValue(AstValue.java:159)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:106)
at com.sun.faces.facelets.component.UIRepeat.getValue(UIRepeat.java:268)
at com.sun.faces.facelets.component.UIRepeat.getDataModel(UIRepeat.java:244)
at com.sun.faces.facelets.component.UIRepeat.setIndex(UIRepeat.java:434)
at com.sun.faces.facelets.component.UIRepeat.doVisitChildren(UIRepeat.java:642)
at com.sun.faces.facelets.component.UIRepeat.visitTree(UIRepeat.java:600)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1487)
at com.sun.faces.facelets.component.UIRepeat.visitTree(UIRepeat.java:606)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1487)
at javax.faces.component.UIForm.visitTree(UIForm.java:331)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1487)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1487)
at com.sun.faces.lifecycle.RestoreViewPhase.deliverPostRestoreStateEvent(RestoreViewPhase.java:258)
at com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:245)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:107)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
答案 0 :(得分：2)
您传递给p.statusId的{{1}}似乎是空的。您可以尝试将commentList(String statusId)置于System.out.println("statusId: "+statusId);方法的开头。
您也可以在{I}之前放置commentList(String statusId)：
<h:outputText value="p.statusId: #{p.statusId}"/>我也不确定将<ui:repeat var="q" value="#{statusBean.commentList(p.statusId)}" >
置于statusBean.commentList(p.statusId) ui:repeat属性中是否合适。您最终可能会比您想要的更频繁地从DB中检索状态列表。最好将它预加载到某个属性，然后在需要的地方传递它。
<强>更新
同时替换：
value与
Query query = em.createQuery(
"SELECT c FROM Comment c WHERE c.statusId=" + statusId, Comment.class);
这样您的查询对SQL注入和语法错误更安全。
更新2
TypedQuery<Comment> query = em.createQuery(
"SELECT c FROM Comment c WHERE c.statusId = :statusId", Comment.class);
query.setParameter("statusId", statusId);
在您的StatusBean中
private class StatusWrapper {
private Status status;
private List<Comment> comments;
}
在您的页面中使用statuses属性。希望它很清楚（可能有一些拼写错误。）