2
我試圖做一些API Spring MVC中。當我運行clearKoszyk方法時：春休眠：TypedQuery NullPointerException異常
$scope.clearKoszyk = function(){
var successCallBack = function(response){
$scope.seans = response.data;
};
var errorCallBack = function(response){
$scope.seans = response.status;
};
$http.post('http://localhost:8080/kino/koszyk/delete').then(successCallBack, errorCallBack);
}
});
我得到響應狀態500錯誤，所以這是一個內部服務器錯誤。
SEVERE: Servlet.service() for servlet [DispatcherServlet] in context with
path [/kino] threw exception [Request processing failed; nested exception
is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at org.hibernate.internal.SessionFactoryImpl.getReturnTypes(SessionFactoryImpl.java:1112)
at org.hibernate.internal.AbstractQueryImpl.getReturnTypes(AbstractQueryImpl.java:192)
at org.hibernate.ejb.AbstractEntityManagerImpl.createNamedQuery(AbstractEntityManagerImpl.java:690)
at sun.reflect.GeneratedMethodAccessor69.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298)
at com.sun.proxy.$Proxy43.createNamedQuery(Unknown Source)
at kino.repositoryImpl.KoszykRepositoryImpl.deleteKoszyk(KoszykRepositoryImpl.java:60)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy50.deleteKoszyk(Unknown Source)
at kino.serviceImpl.KoszykServiceImpl.deleteKoszyk(KoszykServiceImpl.java:50)
at kino.controllers.KoszykController.DeleteKoszyk(KoszykController.java:82)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
所以我覺得這是NPE這裏：
at kino.repositoryImpl.KoszykRepositoryImpl.deleteKoszyk(KoszykRepositoryImpl.java:60)
但我真的不知道是什麼導致這個例外它是由引起的。我正在檢查如果EntityManager或用戶爲空。
56 public void deleteKoszyk(User user) throws NullPointerException{
57
58 if(user != null){
59 if(emManager != null){
60 TypedQuery<Koszyk> query = emManager.createNamedQuery("Koszyk.deleteKoszyk", Koszyk.class);
query.setParameter("id", user.getId());
query.executeUpdate();
}else{
throw new NullPointerException("emManager = null");
}
}else{
throw new NullPointerException("Podany użytkownik nie istnieje");
}
}
這是我的koszyk類。
@Entity
@NamedQuery(name = "Koszyk.deleteKoszyk", query = "DELETE FROM Koszyk k WHERE k.user.id = :id")
@Table(name="Koszyk")
public class Koszyk implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue
@Column(name="Koszyk_id")
private Long id;
@OneToOne
private User user;
@Column(name="Cena")
private int cena;
@Column(name="KoszykItems")
@OneToMany(mappedBy="koszyk", fetch = FetchType.EAGER)
private List<KoszykItem> koszykItems;
這個問題只能說明當我嘗試刪除或ID找到koszyk。我可以從這個實體讀取，我可以用正常的方式顯示它。這是我的KoszykRepository類：
@Repository
@Transactional
public class KoszykRepositoryImpl implements KoszykRepository {
@PersistenceContext
private EntityManager emManager;
public KoszykRepositoryImpl(){
}
@Override
public void update(Koszyk koszyk) {
emManager.merge(koszyk);
}
@Override
public Koszyk deleteKoszykItem(KoszykItem koszykItem, User user) {
Koszyk koszyk = read(user);
List<KoszykItem> listaItemow = koszyk.getKoszykItems();
listaItemow.remove(koszykItem);
koszyk.setKoszykItems(listaItemow);
update(koszyk);
return koszyk;
}
@Override
public void deleteKoszyk(User user) throws NullPointerException{
if(user != null){
if(emManager != null){
TypedQuery<Koszyk> query = emManager.createNamedQuery("Koszyk.deleteKoszyk", Koszyk.class);
query.setParameter("id", user.getId());
query.executeUpdate();
}else{
throw new NullPointerException("emManager = null");
}
}else{
throw new NullPointerException("Podany użytkownik nie istnieje");
}
}
@Override
public void create(User user, Koszyk koszykDoZapisu) {
List<Koszyk> ListaKoszykow = read();
boolean zapisz = true;
if(user == null){
throw new NullPointerException("Zaloguj się!");
}else if(!ListaKoszykow.isEmpty() && ListaKoszykow != null){
for(Koszyk koszyk: ListaKoszykow){
if(koszyk.getUser().getId() == user.getId()){
zapisz = false;
break;
}
}
}
if(zapisz){
koszykDoZapisu.setUser(user);
emManager.persist(koszykDoZapisu);
}
}
@Override
public List<Koszyk> read() {
return emManager.createQuery("SELECT k FROM Koszyk k", Koszyk.class).getResultList();
}
@Override
public Koszyk read(User user) {
List<Koszyk> ListaKoszykow = read();
Koszyk zwracany = new Koszyk();
if(user == null){
throw new NullPointerException("Zaloguj się!");
}
if(ListaKoszykow.isEmpty() || ListaKoszykow == null){
throw new NullPointerException("Dany użytkownik nie ma jeszcze przypisanego koszyka");
}else{
for(Koszyk koszyk: ListaKoszykow){
if(koszyk.getUser().equals(user)){
zwracany = koszyk;
//Hibernate.initialize(zwracany.getKoszykItems());
}
}
}
return zwracany;
}
}
[編輯]
我已經改變了刪除功能，這一點：
public void deleteKoszyk(User user) throws NullPointerException{
if(user != null){
if(emManager != null){
final Query query = emManager.createNamedQuery("Koszyk.deleteKoszyk");
query.setParameter("id", user.getId());
63 final int executeUpdate = query.executeUpdate();
}else{
throw new NullPointerException("emManager = null");
}
}else{
throw new NullPointerException("Podany użytkownik nie istnieje");
}
}
和stacktree是完全地不同：
SEVERE: Servlet.service() for servlet [DispatcherServlet] in context with
path [/kino] threw exception [Request processing failed; nested exception is
javax.persistence.PersistenceException:
org.hibernate.exception.ConstraintViolationException: Cannot delete or
update a parent row: a foreign key constraint fails (`marcin`.`koszykitem`,
CONSTRAINT `FK8F90CFF02AE8E273` FOREIGN KEY (`koszyk_Koszyk_id`) REFERENCES
`koszyk` (`Koszyk_id`))] with root cause
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException:
Cannot delete or update a parent row: a foreign key constraint fails
(`marcin`.`koszykitem`, CONSTRAINT `FK8F90CFF02AE8E273` FOREIGN KEY
(`koszyk_Koszyk_id`) REFERENCES `koszyk` (`Koszyk_id`))
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:932)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2551)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2073)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2009)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5094)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1994)
at sun.reflect.GeneratedMethodAccessor66.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122)
at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
at com.sun.proxy.$Proxy51.executeUpdate(Unknown Source)
at org.hibernate.hql.internal.ast.exec.BasicExecutor.execute(BasicExecutor.java:95)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.executeUpdate(QueryTranslatorImpl.java:413)
at org.hibernate.engine.query.spi.HQLQueryPlan.performExecuteUpdate(HQLQueryPlan.java:283)
at org.hibernate.internal.SessionImpl.executeUpdate(SessionImpl.java:1135)
at org.hibernate.internal.QueryImpl.executeUpdate(QueryImpl.java:116)
at org.hibernate.ejb.QueryImpl.internalExecuteUpdate(QueryImpl.java:183)
at org.hibernate.ejb.AbstractQueryImpl.executeUpdate(AbstractQueryImpl.java:99)
at kino.repositoryImpl.KoszykRepositoryImpl.deleteKoszyk(KoszykRepositoryImpl.java:63)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy48.deleteKoszyk(Unknown Source)
at kino.serviceImpl.KoszykServiceImpl.deleteKoszyk(KoszykServiceImpl.java:50)
at kino.controllers.KoszykController.DeleteKoszyk(KoszykController.java:91)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
你可以把一個斷點在你deleteKoszyk方法登場啦，看看有什麼是空？ – yogidilip
我做到了。我注意到user.koszyk爲null：http://imgur.com/a/Hyyiu。我修正了它：http://imgur.com/a/3EtBQ。但是我仍然遇到同樣的錯誤，我不知道如何檢查可以爲空的東西。錯誤在同一行中完全相同。 – Marcin46