[英]ClassCastException in CRUD operation
我正在尝试添加CRUD操作的产品。起初我没有使用ajax。现在更改了字符串方法以适合ajax。 当我添加产品时,它将引发此异常
“ java.lang.ClassCastException:java.lang.Integer无法转换为com.shop.model.Product”
堆栈分别指向DAO和服务的这些行
return (Product) sessionFactory.getCurrentSession().save(product);
return productDAO.addProduct(product);
模型
@Entity
@Table(name="PRODUCTS")
public class Product {
@Id
@Column(name="ID")
@GeneratedValue
private Integer id;
@NotEmpty
@Column(name="PRODUCT_NAME")
private String productName;
@NotNull
@Min(1)
@Column(name="PRICE")
private BigDecimal price;
@NotNull
@Min(1)
@Column(name="QUANTITY")
private int quantity;
@NotEmpty
@Column(name="description")
private String description;
@ManyToOne
@JoinColumn(name = "categoryId")
private Category category;
// setters and getters
控制器
@RequestMapping("addproduct.html")
public String viewaddProduct(Map model) {
Product product = new Product();
model.put("product", product);
return "addproduct";
}
@RequestMapping(value ="addproduct", method = RequestMethod.POST,
produces = MediaType.APPLICATION_JSON_VALUE,
consumes = MediaType.APPLICATION_JSON_VALUE)
@ResponseBody
public Product addProduct(@RequestBody Product product,
Map model) {
model.put("productList", productService.listProducts());
model.put("categoryList", categoryService.listCategories());
return productService.addProduct(product);
产品展示
public Product addProduct(Product product) {
return (Product) sessionFactory.getCurrentSession().save(product);
}
ProductServiceImpl
@Transactional
public Product addProduct(Product product) {
return productDAO.addProduct(product);
}
JSP
<script>$(document).ready(function() {
$('#Form').submit(function(event) {
var productName = $('#productName').val();
var price = $('#price').val();
var quantity = $('#quantity').val();
var json = { "productName" : productName, "price" : price, "quantity": quantity};
$.ajax({
url: $("#Form").attr( "action"),
data: JSON.stringify(json),
type: "POST",
beforeSend: function(xhr) {
xhr.setRequestHeader("Accept", "application/json");
xhr.setRequestHeader("Content-Type", "application/json");
},
success: function(product) {
var respContent = "";
respContent += "<span class='success'>Product was created: [";
respContent += product.productName + " : ";
respContent += product.price + " : " ;
respContent += product.quantity + "]</span>";
$("#FromResponse").html(respContent);
}
});
event.preventDefault();
});
});</script>
<body>
<div id="FromResponse"></div>
<h3> Form</h3>
<FONT color="blue"></FONT>
<form:form id="Form" action="addproduct.json" commandName="product" method="POST">
<table>
<tr><td>Product Name:<FONT color="red"><form:errors path="productName" /></FONT></td></tr>
<tr><td><form:input path="productName" /></td></tr>
<tr><td>Price:<FONT color="red"><form:errors path="price" /></FONT></td></tr>
<tr><td><form:input path="price" /></td></tr>
<tr><td>Quantity:<FONT color="red"><form:errors path="quantity" /></FONT></td></tr>
<tr><td><form:input path="quantity" /></td></tr>
<tr><td>Category:<FONT color="red"><form:errors path="category.cid" /></FONT></td></tr>
<tr><td><form:input path="category.cid" /></td></tr>
<tr><td>Description:<FONT color="red"><form:errors path="description" /></FONT></td></tr>
<tr><td><form:textarea path="description" cols="65" rows="10"/></td></tr>
<tr><td><input type="submit" value="Add Products" /></td></tr>
</table>
</form:form>
</body>
sessionFactory.getCurrentSession().save(product)
返回类型为java.lang.Integer
的标识符,您正在将其强制转换为com.shop.model.Product
类,因此出现错误。
public Serializable save(String entityName, Object object) throws HibernateException
坚持给定的瞬态实例,首先分配一个生成的标识符。 (或者,如果使用分配的生成器,则使用标识符属性的当前值。)如果关联是通过cascade="save-update"
映射的,则此操作将级联到关联的实例。
参数: object-持久类的瞬时实例
返回:生成的标识符
你可以做什么 ..
sessionFactory.getCurrentSession().save(product);
return product;
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