所以我想从我的数据库中获取数据，但我总是得到这个异常，说我的getAll（）方法返回null。我不知道该怎么办，有人可以帮帮我吗？
由于
WarehouseHasProduct.java
public class WarehouseHasProduct implements java.io.Serializable {
private Integer id;
private Product product = new Product();
private Warehouse warehouse = new Warehouse();
private int stock;
public WarehouseHasProduct() {
}
public WarehouseHasProduct(Product product, Warehouse warehouse, int stock) {
this.product = product;
this.warehouse = warehouse;
this.stock = stock;
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public Product getProduct() {
return this.product;
}
public void setProduct(Product product) {
this.product = product;
}
public Warehouse getWarehouse() {
return this.warehouse;
}
public void setWarehouse(Warehouse warehouse) {
this.warehouse = warehouse;
}
public int getStock() {
return this.stock;
}
public void setStock(int stock) {
this.stock = stock;
}
}
Warehouse.java
public class Warehouse implements java.io.Serializable {
private Integer id;
private String description;
private Set<WarehouseHasProduct> warehouseHasProducts = new HashSet<WarehouseHasProduct>(
0);
public Warehouse() {
}
public Warehouse(String description) {
this.description = description;
}
public Warehouse(String description,
Set<WarehouseHasProduct> warehouseHasProducts) {
this.description = description;
this.warehouseHasProducts = warehouseHasProducts;
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public Set<WarehouseHasProduct> getWarehouseHasProducts() {
return this.warehouseHasProducts;
}
public void setWarehouseHasProducts(
Set<WarehouseHasProduct> warehouseHasProducts) {
this.warehouseHasProducts = warehouseHasProducts;
}
}
Product.java
public class Product implements java.io.Serializable {
private Integer id;
private ProductType productType;
private String productName;
private String description;
private double price;
private Set<WarehouseHasProduct> warehouseHasProducts = new HashSet<WarehouseHasProduct>(
0);
private Set<Order> orders = new HashSet<Order>(0);
public Product() {
}
public Product(ProductType productType, String productName,
String description, double price) {
this.productType = productType;
this.productName = productName;
this.description = description;
this.price = price;
}
public Product(ProductType productType, String productName,
String description, double price,
Set<WarehouseHasProduct> warehouseHasProducts, Set<Order> orders) {
this.productType = productType;
this.productName = productName;
this.description = description;
this.price = price;
this.warehouseHasProducts = warehouseHasProducts;
this.orders = orders;
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public ProductType getProductType() {
return this.productType;
}
public void setProductType(ProductType productType) {
this.productType = productType;
}
public String getProductName() {
return this.productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public double getPrice() {
return this.price;
}
public void setPrice(double price) {
this.price = price;
}
public Set<WarehouseHasProduct> getWarehouseHasProducts() {
return this.warehouseHasProducts;
}
public void setWarehouseHasProducts(
Set<WarehouseHasProduct> warehouseHasProducts) {
this.warehouseHasProducts = warehouseHasProducts;
}
public Set<Order> getOrders() {
return this.orders;
}
public void setOrders(Set<Order> orders) {
this.orders = orders;
}
}
WarehouseHasProduct.hbm.xml
<hibernate-mapping>
<class name="com.app.hibernate.data.WarehouseHasProduct" table="warehouse_has_product" catalog="test">
<id name="id" type="java.lang.Integer">
<column name="id" />
<generator class="identity" />
</id>
<many-to-one name="product" class="com.app.hibernate.data.Product" fetch="select">
<column name="product_id" not-null="true" />
</many-to-one>
<many-to-one name="warehouse" class="com.app.hibernate.data.Warehouse" fetch="select">
<column name="warehouse_id" not-null="true" />
</many-to-one>
<property name="stock" type="int">
<column name="stock" not-null="true" />
</property>
</class>
</hibernate-mapping>
Warehouse.hbm.xml
<hibernate-mapping>
<class name="com.app.hibernate.data.Warehouse" table="warehouse" catalog="test">
<id name="id" type="java.lang.Integer">
<column name="id" />
<generator class="identity" />
</id>
<property name="description" type="string">
<column name="description" length="100" not-null="true" />
</property>
<set name="warehouseHasProducts" table="warehouse_has_product" inverse="true" lazy="true" fetch="select">
<key>
<column name="warehouse_id" not-null="true" />
</key>
<one-to-many class="com.app.hibernate.data.WarehouseHasProduct" />
</set>
</class>
</hibernate-mapping>
Product.hbm.xml
<hibernate-mapping>
<class name="com.app.hibernate.data.Product" table="product" catalog="test">
<id name="id" type="java.lang.Integer">
<column name="id" />
<generator class="identity" />
</id>
<many-to-one name="productType" class="com.app.hibernate.data.ProductType" fetch="select">
<column name="type_id" not-null="true" />
</many-to-one>
<property name="productName" type="string">
<column name="productName" length="100" not-null="true" />
</property>
<property name="description" type="string">
<column name="description" length="100" not-null="true" />
</property>
<property name="price" type="double">
<column name="price" precision="22" scale="0" not-null="true" />
</property>
<set name="warehouseHasProducts" table="warehouse_has_product" inverse="true" lazy="true" fetch="select">
<key>
<column name="product_id" not-null="true" />
</key>
<one-to-many class="com.app.hibernate.data.WarehouseHasProduct" />
</set>
<set name="orders" table="order_has_product" inverse="false" lazy="true" fetch="select">
<key>
<column name="product_id" not-null="true" />
</key>
<many-to-many entity-name="com.app.hibernate.data.Order">
<column name="order_id" not-null="true" />
</many-to-many>
</set>
</class>
</hibernate-mapping>
WarehouseHasProductService.java
@Component
public class WarehouseHasProductService {
@Autowired
private SessionFactory sessionFactory;
public SessionFactory getSessionFactory() {
return sessionFactory;
}
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}
@Transactional
public void register(WarehouseHasProduct whp){
// Acquire session
Session session = sessionFactory.getCurrentSession();
// Save employee, saving behavior get done in a transactional manner
session.save(whp);
}
@SuppressWarnings("unchecked")
@Transactional
public List<WarehouseHasProduct> getAll(){
// Acquire session
Session session = sessionFactory.getCurrentSession();
List list = session.createQuery("from com.app.hibernate.data.WarehouseHasProduct").list();
return list;
}
}
RegisterWarehouseHasProduct.java
@ManagedBean
@SessionScoped
public class RegisterWarehouseHasProduct{
@ManagedProperty("#{whpService}")
private WarehouseHasProductService whpService;
private WarehouseHasProduct whp = new WarehouseHasProduct();
public WarehouseHasProductService getWhpService() {
return whpService;
}
public void setWhpService(WarehouseHasProductService whpService) {
this.whpService = whpService;
}
public WarehouseHasProduct getWhp() {
return whp;
}
public void setWhp(WarehouseHasProduct whp) {
this.whp = whp;
}
public String register() {
// Calling Business Service
whpService.register(whp);
// Add message
FacesContext.getCurrentInstance().addMessage(null,
new FacesMessage("The Product "+whp.getId()+" Is Registered Successfully"));
return "";
}
public List<WarehouseHasProduct> getAll(){
return whpService.getAll();
}
}
Home.xhtml
<p:dataTable var="p" value="#{registerProduct.getAllProducts()}">
<f:facet name="header">
Products List
</f:facet>
<p:column headerText="Code">
<h:outputText value="#{p.id}" />
</p:column>
<p:column headerText="Name">
<h:outputText value="#{p.productName}" />
</p:column>
<p:column headerText="Description">
<h:outputText value="#{p.description}" />
</p:column>
<p:column headerText="Type">
<h:outputText value="#{p.productType.description}" />
</p:column>
<p:column headerText="Price">
<h:outputText value="#{p.price}" />
</p:column>
</p:dataTable>
我真的很感激答案。谢谢！