[英]Spring-boot + Hibernate + JPA with transient fields
This is my first question, but I have been looking for a solution for 2 days, with no success. 这是我的第一个问题,但是我一直在寻找解决方案已有2天,但没有成功。 In my project, I have a
User
entity with a transient property: 在我的项目中,我有一个带有过渡属性的
User
实体:
@Transient
@JsonProperty
private List<String> files;
I have no setter, and getter is: 我没有二传手,而getter是:
public List<String> getFiles() {
/* Call one static method */
}
Executing the application with NetBeans in debug, works fine, and from javascript, I can get the getFiles results, using user.fotos
. 使用NetBeans在调试中执行应用程序可以正常工作,并且可以从
user.fotos
使用user.fotos
获得getFiles结果。 But when I generate .jar file, and I execute the application with command java -jar app.jar
, by calling one Rest function that must return one User
object, I get this exception: 但是,当我生成.jar文件并使用命令
java -jar app.jar
执行应用程序时,通过调用必须返回一个User
对象的一个Rest函数,我得到了以下异常:
2015-10-28 14:39:35.963 WARN 27836 --- [nio-7777-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: (was java.lang.NullPointerException) (through reference chain: com.pfc.soriano.wsdbmodel.entity.User["files"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: com.pfc.soriano.wsdbmodel.entity.User["files"])
2015-10-28 14:39:35.963 WARN 27836 --- [nio-7777-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Handler execution resulted in exception: Could not write content: (was java.lang.NullPointerException) (through reference chain: com.pfc.soriano.wsdbmodel.entity.User["files"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: com.pfc.soriano.wsdbmodel.entity.User["files"])
My question is: What is Netbeans doing different from command line java -jar, which makes it work fine? 我的问题是:Netbeans与命令行java -jar有什么不同,这使其可以正常工作?
Trying to find some documentation more, I found this: JPA Transient Annotation and JSON 尝试查找更多文档,我发现了这一点: JPA瞬态注释和JSON
Thanks to Damien, finally I have my project working fine: Main Application.java: 多亏了Damien,终于使我的项目工作正常:Main Application.java:
@SpringBootApplication
public class Application extends WebMvcConfigurerAdapter {
/* Here we register the Hibernate4Module into an ObjectMapper, then set this custom-configured ObjectMapper
* to the MessageConverter and return it to be added to the HttpMessageConverters of our application*/
public MappingJackson2HttpMessageConverter jacksonMessageConverter() {
MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter();
ObjectMapper mapper = new ObjectMapper();
Hibernate4Module hm = new Hibernate4Module();
hm.disable(Hibernate4Module.Feature.USE_TRANSIENT_ANNOTATION);
mapper.registerModule(hm);
messageConverter.setObjectMapper(mapper);
return messageConverter;
}
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(jacksonMessageConverter());
super.configureMessageConverters(converters);
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
User entity Class: 用户实体类:
@Entity
@Table(name = "user")
public class User implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "ID")
private Long id;
@Transient
Collection<String> files;
public Long getId() {
files = Utils.getImages("" + id, "src/main/webapp/user/");
return id;
}
public void setId(Long id) {
this.id = id;
}
public Collection<String> getFiles() {
return files;
}
public void setFiles(Collection<String> files) {
this.files = files;
}
}
UserDAO interface: UserDAO界面:
@RepositoryRestResource(collectionResourceRel = "users", itemResourceRel = "users")
public interface UserDAO extends JpaRepository<User, Long> {
}
UserController: UserController:
@Controller
@RequestMapping(value = "user")
public class UserController {
@Autowired
UserDAO userDAO;
@RequestMapping(value = "findById", method = RequestMethod.POST)
@ResponseBody
public User findById(@Param("id") Long id) {
return userDAO.findOne(id);
}
}
Javascript function: JavaScript函数:
function loadUser(id) {
$.ajax({
type: "POST",
url: serviceBaseUrl + "user/findById",
data: {id: id},
contentType: "application/x-www-form-urlencoded; charset=UTF-8",
success: function (data, textStatus, jqXHR) {
if(data) {
alert(data.files);
/* DO SOMETHING ELSE */
}
},
error: function (jqXHR, textStatus, errorThrown) {
console.log(jqXHR.responseJSON.message);
}
});
}
The result is that javascript show me an alert with the file names that exists on the server. 结果是javascript向我显示了服务器上存在的文件名的警报。
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