JasperException: java.lang.IllegalStateException: BindingResult和bean名称'user‘的普通目标对象都不能用作请求属性
JasperException: java.lang.IllegalStateException: BindingResult和bean名称'user‘的普通目标对象都不能用作请求属性
提问于 2017-03-12 06:02:37
我有两个数据模型: User和Car，User可以有很多cars，所以这是User Class：
@Entity
@Table(name="APP_USER")
public class User implements Serializable{
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;
......
@OneToMany(mappedBy="user",cascade=CascadeType.ALL)
private Set<Car> cars = new HashSet<Car>();Car.java：
@Entity
public class Car implements Serializable {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private int id ;
.....
@ManyToOne(optional=false)
@JoinColumn(name="user_fk")
private User user;在carController中，我有为一个用户添加新车的方法：
@Controller
@RequestMapping("/cars")
public class CarController {
@Autowired
CarService carService;
@Autowired
UserService userService;
@RequestMapping(value={"/list"},method=RequestMethod.GET)
public String listCars(ModelMap model){
List<Car> cars = carService.allCars();
model.addAttribute("cars", cars);
return "car"; }
@ModelAttribute("utilisateurs")
public List<User> allUsers(){
List<User> utilisateurs = userService.findAllUsers();
return utilisateurs;
}
@RequestMapping(value={"/newCar"},method=RequestMethod.GET)
public String newCar(ModelMap model){
Car car = new Car();
model.addAttribute("car",car);
return "carRegistration";
}
@RequestMapping(value={"newCar"},method=RequestMethod.POST)
public String newCar(@Valid Car car, BindingResult result,ModelMap model){
if (result.hasErrors()) {
return "registration";
}
carService.save(car);
model.addAttribute("car",car);
return "redirect:/cars/list";
}最后，在视图中，表单是：
<form:form method="POST" modelAttribute="car"
class="form-horizontal">
<form:input type="hidden" path="id" id="id" />
<div class="control-group">
<label class="control-label">Libelle</label>
<div class="controls">
<form:input type="text" path="libelle" id="libelle" style="height:4%" />
</div>
</div>
<div class="control-group">
<label class="control-label">Registration</label>
<div class="controls">
<form:input type="text" path="registration" id="email" />
</div>
</div>
<div class="control-group">
<label class="control-label">Utilisateur</label>
<div class="controls">
<form:select path="user" items="${utilisateurs}" itemValue="id" itemLabel="lastName" style="margin-left: 4%;"></form:select>
</div>
</div>
<div class="form-actions">
<input type="submit" value="Validate" class="btn btn-success" />
</div>
</form:form>我可以获得视图，但是当我单击按钮submit时，我得到这个错误：
Neither BindingResult nor plain target object for bean name 'user' available as request attribute.我认为用户的选择项目有问题!！
回答 1
Stack Overflow用户
回答已采纳
发布于 2017-03-12 07:12:12
您是否为用户提供了任何Spring转换器或格式化程序？
applicationContext.xml：
<bean id="conversionService"
class="org.springframework.context.support.ConversionServiceFactoryBean">
<property name="converters">
<list>
<bean class="my.project.StringToUser"/>
<bean class="my.project.StringToRole"/>
</list>
</property>
</bean>
<mvc:annotation-driven conversion-service="conversionService" />它会将用户id转换为用户对象。
my.project.StringToUser：
import org.springframework.core.convert.converter.Converter;
public class StringToUser implements Converter<String, JUser> {
@Autowired
private UserService userService;
@Override
public JUser convert(String source) {
long id = Long.valueOf(source);
return userService.get(id);
}
}错误：
WARNING: Failed to bind request element: org.springframework.beans.TypeMismatchException:
Failed to convert value of type [com.websystique.springmvc.model.User] to required type [com.websystique.springmvc.model.User];
nested exception is org.springframework.core.convert.ConversionFailedException:
Failed to convert from type [com.websystique.springmvc.model.User] to
type [@org.springframework.web.bind.annotation.ModelAttribute @javax.validation.Valid com.websystique.springmvc.model.User]
for value 'User [id=null, ssoId=alaa, password=alaa1991, firstName=, lastName=, email=, userProfiles=null, accounts=null, userDocuments=[], cars=[], documents=[]]';
nested exception is java.lang.ClassCastException:
com.websystique.springmvc.model.User cannot be cast to java.lang.String页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/42741183
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