Java 自定义验证器有多个问题

我想在Spring MVC Web App中实现自定义验证，但我有多个I问题，我有两个实体

@Entity
public class Foo implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;        
    private String title;       
    @ManyToMany(fetch=FetchType.EAGER, cascade = { CascadeType.MERGE })
    @JoinTable(name = "foos_bars",
                joinColumns = @JoinColumn(name = "foos_id"),
                inverseJoinColumns = @JoinColumn(name = "bars_id"))
    private List<Bar> bars;
}

形式是

<form:form commandName="foo" class="form" id="add-foo">
    <form:input path="title"/>
    <form:errors path="title"/>
    <button>Add</button>        
</form:form>

我发现应该有一个新的

@InitBinder

方法，其名称以这种方式声明

@InitBinder("foo")
    public void initBinderValidator(WebDataBinder binder) {
        binder.addValidators(fooValidator);     
    }

但我还是得到了与上面提到的相同的错误。

---

这些问题的任何解决方案请

我认为您只需要在验证器的supports方法中包括Foo和Bar类，如下所示：

@Override
public boolean supports(Class<?> clazz) {
    return Foo.class.isAssignableFrom(clazz) ||
           Bar.class.isAssignableFrom(clazz);
}

@覆盖
公共布尔支持（类clazz）{
返回Foo.class.isAssignableFrom（clazz）||
Bar.class.isAssignableFrom（clazz）；
}

我认为您只需要在验证器的supports方法中包括Foo和Bar类，如下所示：

@Override
public boolean supports(Class<?> clazz) {
    return Foo.class.isAssignableFrom(clazz) ||
           Bar.class.isAssignableFrom(clazz);
}

@覆盖
公共布尔支持（类clazz）{
返回Foo.class.isAssignableFrom（clazz）||
Bar.class.isAssignableFrom（clazz）；
}

您可以通过下面的文章了解有关SpringMVC中自定义验证器的更多信息。通过下面的文章，您可以了解有关SpringMVC中自定义验证器的更多信息。

<form:form commandName="foo" class="form" id="add-foo">
    <form:input path="title"/>
    <form:errors path="title"/>
    <button>Add</button>        
</form:form>

java.lang.IllegalStateException: Invalid target for Validator [com.exam.FooValidator@1e2c656]: Bar [title=null]
    at org.springframework.validation.DataBinder.assertValidators(DataBinder.java:516)
    at org.springframework.validation.DataBinder.addValidators(DataBinder.java:527)
    at com.eaxm.FooController.initBinderOne(FooController.java:36)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at org.springframework.web.method.annotation.InitBinderDataBinderFactory.initBinder(InitBinderDataBinderFactory.java:62)
    at org.springframework.web.bind.support.DefaultDataBinderFactory.createBinder(DefaultDataBinderFactory.java:53)
    at org.springframework.web.method.annotation.ModelFactory.updateBindingResult(ModelFactory.java:251)
    at org.springframework.web.method.annotation.ModelFactory.updateModel(ModelFactory.java:235)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.getModelAndView(RequestMappingHandlerAdapter.java:879)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:782)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:957)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

@InitBinder("foo")
    public void initBinderValidator(WebDataBinder binder) {
        binder.addValidators(fooValidator);     
    }

@Override
public boolean supports(Class<?> clazz) {
    return Foo.class.isAssignableFrom(clazz) ||
           Bar.class.isAssignableFrom(clazz);
}