我正在尝试创建新对象并将其持久保存在DB中。在项目中，我有Spring-boot，Hibernate和Thymeleaf。
要提供数据，我使用以下表格：
<body>
<form th:object="${malt}" th:action="@{/malt/}" method="post">
<input type="hidden" th:field="*{id}" />
<label>Malt name:</label>
<input type="text" class="form-control" th:field="*{maltName}" />
<label>Producer:</label>
<input type="text" class="form-control"
th:field="*{producer.producerName}" />
<label>Country:</label>
<select class="form-control" th:field="*{country.id}">
<option value="0">Select country</option>
<option th:each="country : ${countries}"
th:value="${country?.id}"
th:text="${country?.countryName}">
</option>
</select>
<label>Malt filling:</label>
<input type="text" class="form-control"
th:field="*{maltFilling}" />
<label>Malt usage:</label>
<input type="text" class="form-control"
th:field="*{maltUsage}" />
<label>Malt EBC:</label>
<input type="number" class="form-control"
th:field="*{maltEbc}" />
<button class="submit-button" type="submit">Submit</button>
</form>
</body>
我要保留的对象：
@Setter
@Getter
@NoArgsConstructor
@Entity
@ToString
@Table(name="malt")
public class Malt extends BaseEntity {
@Column(name="malt_name")
private String maltName;
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="producer_id")
private Producer producer;
@Column(name="malt_filling")
private int maltFilling;
@Column(name="malt_ebc")
private int maltEbc;
@Column(name="malt_usage")
private String maltUsage;
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="country_id")
private Country country;
@ManyToMany(mappedBy="malts")
private Set<Batch> batches;
@Builder
public Malt(Long id, String maltName, String producerName, Country country, Producer producer, int maltFilling, int maltEbc, String maltUsage) {
super(id);
this.maltName = maltName;
this.producer = producer;
this.maltFilling = maltFilling;
this.maltEbc = maltEbc;
this.maltUsage = maltUsage;
this.country = country;
}
BaseEntity：
@Setter
@Getter
@NoArgsConstructor
@AllArgsConstructor
@MappedSuperclass
public class BaseEntity implements Serializable{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
public boolean isNew() {
return this.id == null;
}
}
MaltController的一部分：
@InitBinder
public void setAllowedFields(WebDataBinder dataBinder) {
dataBinder.setDisallowedFields("id");
}
@GetMapping("/new")
public String initCreationForm(Model model) {
Malt malt = new Malt();
model.addAttribute("malt", malt);
return VIEWS_MALT_CREATE_OR_UPDATE_FORM;
}
@PostMapping("/new")
public String processCreationForm(@Valid Malt malt, BindingResult result, ModelMap model) {
if (StringUtils.hasLength(malt.getMaltName()) && malt.isNew()) {
result.rejectValue("maltName", "duplicate", "already exists");
}
if (result.hasErrors()) {
model.put("malt", malt);
return VIEWS_MALT_CREATE_OR_UPDATE_FORM;
} else {
Malt savedMalt = maltService.save(malt);
return "redirect:/malt/" + savedMalt.getId();
}
}
@GetMapping("/{maltId}")
public ModelAndView showMalt(@PathVariable("maltId") Long maltId) {
ModelAndView mav = new ModelAndView("malt/malt-show");
mav.addObject(maltService.findById(maltId));
return mav;
}
当我按下Submit按钮时，出现以下错误：
There was an unexpected error (type=Bad Request, status=400).
Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "null"
org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "null"
Caused by: java.lang.NumberFormatException: For input string: "null"
在调试日志级别，有以下日志：
Field [id] has been removed from PropertyValues and will not be bound, because it has not been found in the list of allowed fields
Start processing with input [id=&maltName=Dupa&producer.id=1&country.id=1&maltFilling=12&maltUsage=csd&maltEbc=34]
完整的堆栈跟踪：
There was an unexpected error (type=Bad Request, status=400).
Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "null"
org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "null"
at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:132)
at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:126)
at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:166)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NumberFormatException: For input string: "null"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Long.parseLong(Long.java:589)
at java.lang.Long.valueOf(Long.java:803)
at org.springframework.util.NumberUtils.parseNumber(NumberUtils.java:214)
at org.springframework.beans.propertyeditors.CustomNumberEditor.setAsText(CustomNumberEditor.java:115)
at org.springframework.beans.TypeConverterDelegate.doConvertTextValue(TypeConverterDelegate.java:429)
at org.springframework.beans.TypeConverterDelegate.doConvertValue(TypeConverterDelegate.java:402)
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:155)
at org.springframework.beans.TypeConverterSupport.convertIfNecessary(TypeConverterSupport.java:73)
at org.springframework.beans.TypeConverterSupport.convertIfNecessary(TypeConverterSupport.java:53)
at org.springframework.validation.DataBinder.convertIfNecessary(DataBinder.java:693)
at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:124)
... 51 more
我可以假设发生此错误，因为未生成ID。这很奇怪，因为在BaseEntity中我有这个：
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
我无法在google中找到任何解决方案，这就是为什么我在这里发布问题。
链接到整个项目，我git：https://github.com/fangirsan/maruszka-new
答案 0 :(得分：0)
尝试在实体的// super(id);构造函数中注释掉@builder。通过这样做，您的表单将显式设置id，并且在POST调用期间不应这样做。它必须由持久层生成。该错误如此说明-Failed to convert value of type 'java.lang.String' to required type 'java.lang.Long'; nested exception is java.lang.NumberFormatException: For input string: "null"
您的调试跟踪也显示以下内容：
Start processing with input [id=&maltName=Dupa&producer.id=1&country.id=1&maltFilling=12&maltUsage=csd&maltEbc=34]
它将在ID中传递空/空白字符串。
答案 1 :(得分：0)
问题在于：
<form th:object="${malt}" th:action="@{${'/malt/' + malt.id + '/edit'}}" method="post">
Id未设置，这导致了错误。更改th:action后，它开始起作用。