我得到了NullPointerException，我不知道为什么会在这里。
TemplateController.java
@Controller
@SessionAttributes({"user","initiative"})
public class TemplateController {
@Autowired
private TaskService taskService;
@Autowired
private InitiativeService initiativeService;
@RequestMapping(value = "/addtasktemplate/{taskTemplateObjectId}/{initiativeId}", method = RequestMethod.POST)
public
@ResponseBody
@Transactional(propagation = Propagation.REQUIRED)
String addTaskTemplateUnderInitiative(@PathVariable Integer taskTemplateObjectId, @PathVariable Integer initiativeId, ModelMap model){
User user = (User) model.get("user");
if(user!=null){
Initiative initiative = (Initiative) model.get("initiative");
Boolean check = taskService.addTask(initiative.getInitiativeId(), taskTemplateObjectId, user); //TemplateController.java:67
if(check){
return "successfull";
}else{
return "failure";
}
}
return "Not Eligible";
}
}
函数addTask中调用的函数addTaskTemplateUnderInitiative在TaskDaoImpl.java中定义，其代码为： -
TaskDaoImpl.java
@Repository("TaskDao")
public class TaskDaoImpl implements TaskDao {
private EntityManager entitymanager;
@Autowired
private ObjectInitiativeDao objectInitiativeDao;
@Autowired
private ActionListDao actionListDao;
@PersistenceContext
public void setEntitymanager(EntityManager entitymanager) {
this.entitymanager = entitymanager;
}
@Override
@Transactional(readOnly = false)
public Boolean createTask(Task task) {
try{
entitymanager.persist(task);
return true;
}catch(Exception e){
return false;
}
}
@Override
@Transactional
public Boolean addTask(Integer initiativeId, Integer taskTemplateObjectId, User user) {
ObjectInitiative objectInitiative = objectInitiativeDao.getObjectInitiativeByObjectId(taskTemplateObjectId, false);
Task task = getTaskById(objectInitiative.getRespectiveId());
ObjectInitiative newObject = new ObjectInitiative();
/* Values set for newObject*/
objectInitiativeDao.createObjectInitiative(newObject);
Task newTask = new Task();
/* Values set for newTask */
createTask(newTask);
for(ActionList actionList : task.getActionLists()){
actionListDao.addActionList(newTask.getTaskId(), actionList.getObjectInitiative().getObjectId(), user); //TaskDaoImpl.java:105
}
return true;
}
@Override
@Transactional
public Task getTaskById(Integer taskId) {
Task task = entitymanager.find(Task.class, taskId);
for(ActionList actionList : task.getActionLists()){ //TaskDaoImpl.java:126
Hibernate.initialize(actionList);
}
return task;
}
}
此处，函数addActionList中调用的函数addTask在ActionListDaoImpl.java中定义，其代码为： -
ActionListDaoImpl.java
@Repository("ActionListDao")
public class ActionListDaoImpl implements ActionListDao {
private final Logger logger=LoggerFactory.getLogger(getClass());
private EntityManager entitymanager;
@Autowired
private ObjectInitiativeDao objectInitiativeDao;
@Autowired
private TaskDao taskDao;
@Autowired
private ActionDao actionDao;
@PersistenceContext
public void setEntitymanager(EntityManager entitymanager) {
this.entitymanager = entitymanager;
}
@Override
@Transactional(readOnly = false)
public Boolean createActionList(ActionList actionList) {
try {
entitymanager.persist(actionList);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
@Override
@Transactional
public Boolean addActionList(Integer taskId, Integer actionListTemplateObjectId, User user) {
ObjectInitiative objectInitiative = objectInitiativeDao.getObjectInitiativeByObjectId(actionListTemplateObjectId, false);
ActionList actionList = getActionListById(objectInitiative.getRespectiveId());
Task task = taskDao.getTaskById(taskId); //ActionListDaoImpl.java:67
ObjectInitiative newObject = new ObjectInitiative();
/* Values set for newObject */
objectInitiativeDao.createObjectInitiative(newObject);
ActionList newActionList = new ActionList();
/* Values set for newActionList */
createActionList(newActionList);
return true;
}
@Override
@Transactional(readOnly = true)
public ActionList getActionListById(Integer actionListId) {
return entitymanager.find(ActionList.class, actionListId);
}
}
而且，Task，ObjectInitiative和ActionList的域名是： -
Task.java
@Entity
@Table(name = "task")
@Access(AccessType.FIELD)
public class Task {
@Id
@GenericGenerator(name = "task", strategy = "increment")
@GeneratedValue(generator = "task")
private Integer taskId;
@Column
private Integer objectId;
@Column
private Integer initiativeId;
@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "initiativeId", insertable = false, updatable = false, unique = true, nullable = false)
private Initiative initiative;
@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "objectId", insertable = false, updatable = false, unique = true, nullable = false)
private ObjectInitiative objectInitiative;
@OneToMany(mappedBy = "taskId", fetch = FetchType.LAZY)
private List<ActionList> actionLists;
/* Getters, Setters and toString() */
}
ActionList.java
@Entity
@Table(name = "actionlist")
@Access(AccessType.FIELD)
public class ActionList {
@Id
@GenericGenerator(name = "actionlist", strategy = "increment")
@GeneratedValue(generator = "actionlist")
private Integer actionListId;
@Column
private Integer objectId;
@Column
private Integer taskId;
@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "taskId", insertable = false, updatable = false, unique = true, nullable = false)
private Task task;
@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "objectId", insertable = false, updatable = false, unique = true, nullable = false)
private ObjectInitiative objectInitiative;
/* Getters, Setters and toString() */
}
ObjectInitiative.java
@Entity
@Table(name = "objectinitiative")
@Access(AccessType.FIELD)
public class ObjectInitiative {
@Id
@GenericGenerator(name = "objectinitiative", strategy = "increment")
@GeneratedValue(generator = "objectinitiative")
private Integer objectId;
/* Getters, Setters and toString() */
}
现在，我在'TaskDaoImpl.java'中获取NullPointerException，然后在'ActionListDaoImpl.java'中获取，如日志中所示： -
java.lang.NullPointerException
at org.abc.def.dao.TaskDaoImpl.getTaskById(TaskDaoImpl.java:126)
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:483)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy687.getTaskById(Unknown Source)
at org.abc.def.dao.ActionListDaoImpl.addActionList(ActionListDaoImpl.java:67)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy686.addActionList(Unknown Source)
at org.abc.def.dao.TaskDaoImpl.addTask(TaskDaoImpl.java:105)
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:483)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy687.addTask(Unknown Source)
at org.abc.def.service.TaskServiceImpl.addTask(TaskServiceImpl.java:28)
at org.abc.def.controller.TemplateController.addTaskTemplateUnderInitiative(TemplateController.java:67)
at org.abc.def.controller.TemplateController$$FastClassByCGLIB$$4c5d2b90.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:698)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:631)
at org.abc.def.web.controller.sim.TemplateController$$EnhancerByCGLIB$$7697f039_2.addTaskTemplateUnderInitiative(<generated>)
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:483)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:644)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:301)
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 org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
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:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:136)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:74)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1015)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:652)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1575)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1533)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
在这里，您可以看到我正在使用现有任务模板，而不是创建新任务。当我获取任务时发生异常，但是当我创建新任务（不使用现有任务模板）然后获取它时，这不会发生。
这一切都结束了。我无法理解如何解决这个问题。
答案 0 :(得分：0)
我认为你应该检查Null TemplateController.java
中方法 addTaskTemplateUnderInitiative 的计划对象@Controller
@SessionAttributes({"user","initiative"})
public class TemplateController {
@Autowired
private TaskService taskService;
@Autowired
private InitiativeService initiativeService;
@RequestMapping(value = "/addtasktemplate/{taskTemplateObjectId}/{initiativeId}", method = RequestMethod.POST)
public
@ResponseBody
@Transactional(propagation = Propagation.REQUIRED)
String addTaskTemplateUnderInitiative(@PathVariable Integer taskTemplateObjectId, @PathVariable Integer initiativeId, ModelMap model){
User user = (User) model.get("user");
if(user!=null){
Initiative initiative = (Initiative) model.get("initiative");
if(initiative != null){
Boolean check = taskService.addTask(initiative.getInitiativeId(), taskTemplateObjectId, user);
model.addAttribute("initiative", initiativeService.getInitiativeByInitiativeId(initiativeId));
if(check){
return "successfull";
}else{
return "failure";
}
} else return "Falid";
}
return "Not Eligible";
}
}
答案 1 :(得分：0)
你检查了下面的代码。
for(ActionList actionList : task.getActionLists()){ //TaskDaoImpl.java:126
Hibernate.initialize(actionList);
}
1。）您的task is null。
2。）如果task不为null，那么task.getActionLists() is null。对于每个人都会在这里给出错误
以上可能是no mapping data找到或以某种方式Hibernate is not able to fetch the list。
是列表Lazy，如果是，则在for循环之前尝试初始化。
您可以将actionList置于Task内Eager，它应该可以正常工作，但这不是您问题的解决方案。
问题主要是因为actionList无法正确初始化。
Hibernate.initialize(task.getActionLists());