我正在为 requestfactories 和泛型而苦苦挣扎。 在下面的代码中,代理方法与实体方法完全匹配,但我得到了日志跟踪:
java.lang.NullPointerException: null
at com.google.web.bindery.autobean.vm.impl.MethodPropertyContext.traverse(MethodPropertyContext.java:102) ~[gwt-servlet-2.6.0.jar:na]
at com.google.web.bindery.autobean.vm.impl.MethodPropertyContext.accept(MethodPropertyContext.java:75) ~[gwt-servlet-2.6.0.jar:na]
at com.google.web.bindery.autobean.shared.impl.AutoBeanCodexImpl$PropertyCoderCreator.maybeCreateCoder(AutoBeanCodexImpl.java:353) ~[gwt-servlet-2.6.0.jar:na]
at com.google.web.bindery.autobean.shared.impl.AutoBeanCodexImpl$PropertyCoderCreator.visitReferenceProperty(AutoBeanCodexImpl.java:341) ~[gwt-servlet-2.6.0.jar:na]
at com.google.web.bindery.autobean.vm.impl.ProxyAutoBean.traverseProperties(ProxyAutoBean.java:324) ~[gwt-servlet-2.6.0.jar:na]
at com.google.web.bindery.autobean.shared.impl.AbstractAutoBean.traverse(AbstractAutoBean.java:166) ~[gwt-servlet-2.6.0.jar:na]
...
我的代理类:
@ProxyFor(value = OutilLibre.class, locator = OutilLibreLocator.class)
public interface OutilLibreProxy extends ProxyWithId, ProxyWithCartoLibre<OutilProxy>, EntityProxy {
public Long getId();
public void setId(Long id);
@Override
OutilProxy getCompetence();
@Override
void setCompetence(OutilProxy outil);
@Override
String getCompetenceAutre();
@Override
void setCompetenceAutre(String competence);
}
与泛型的接口(interface):
public interface ProxyWithCartoLibre<T> {
T getCompetence();
void setCompetence(T competence);
String getCompetenceAutre();
void setCompetenceAutre(String competence);
}
对应的服务器实体:
@Entity
@Table(name = "outil_libre")
public class OutilLibre extends AEntityLongId implements IBeanCartoLibre<Outil>, IUniqueVersionEntity {
private static final long serialVersionUID = 45107725880220830L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO, generator = "outil_libre_seq_gen")
@SequenceGenerator(name = "outil_libre_seq_gen", sequenceName = "seq_outil_libre")
@Column(name = "id", unique = true, nullable = false, precision = 5, scale = 0)
private Long id;
@Cascade(value = {org.hibernate.annotations.CascadeType.SAVE_UPDATE})
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "outil", nullable = false)
private Outil outil;
@Column(name = "outil_autre")
private String outilAutre;
@Override
public Long getId() {
return id;
}
@Override
public void setId(Long id) {
this.id = id;
}
@Override
public Outil getCompetence() {
return outil;
}
@Override
public void setCompetence(Outil outil) {
this.outil = outil;
}
@Override
public String getCompetenceAutre() {
return outilAutre;
}
@Override
public void setCompetenceAutre(String competence) {
this.outilAutre = competence;
}
}
我不知道为什么会出现此错误,因为 ProxyWithCartoLibre 接口(interface)仅供客户端类使用,在定义 requestfactory 时没有任何目的。
有没有办法告诉 GWT 生成器排除 ProxyWithCartoLibre 接口(interface)?
提前致谢。
编辑
java.lang.NullPointerException: null
at com.google.web.bindery.autobean.vm.impl.MethodPropertyContext.traverse(MethodPropertyContext.java:102) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.vm.impl.MethodPropertyContext.accept(MethodPropertyContext.java:75) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AutoBeanCodexImpl$PropertyCoderCreator.maybeCreateCoder(AutoBeanCodexImpl.java:353) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AutoBeanCodexImpl$PropertyCoderCreator.visitReferenceProperty(AutoBeanCodexImpl.java:341) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.vm.impl.ProxyAutoBean.traverseProperties(ProxyAutoBean.java:324) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AbstractAutoBean.traverse(AbstractAutoBean.java:166) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AbstractAutoBean.accept(AbstractAutoBean.java:101) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AutoBeanCodexImpl.doCoderFor(AutoBeanCodexImpl.java:522) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AbstractAutoBean.setProperty(AbstractAutoBean.java:276) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.vm.impl.ProxyAutoBean.setProperty(ProxyAutoBean.java:253) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.vm.impl.BeanPropertyContext.set(BeanPropertyContext.java:44) ~[gwt-servlet.jar:na]
at com.google.web.bindery.requestfactory.server.Resolver$PropertyResolver.visitValueProperty(Resolver.java:211) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.vm.impl.ProxyAutoBean.traverseProperties(ProxyAutoBean.java:289) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AbstractAutoBean.traverse(AbstractAutoBean.java:166) ~[gwt-servlet.jar:na]
at com.google.web.bindery.autobean.shared.impl.AbstractAutoBean.accept(AbstractAutoBean.java:101) ~[gwt-servlet.jar:na]
at com.google.web.bindery.requestfactory.server.Resolver.resolveClientValue(Resolver.java:470) ~[gwt-servlet.jar:na]
at com.google.web.bindery.requestfactory.server.SimpleRequestProcessor.processInvocationMessages(SimpleRequestProcessor.java:491) ~[gwt-servlet.jar:na]
at com.google.web.bindery.requestfactory.server.SimpleRequestProcessor.process(SimpleRequestProcessor.java:233) ~[gwt-servlet.jar:na]
at com.google.web.bindery.requestfactory.server.SimpleRequestProcessor.process(SimpleRequestProcessor.java:135) ~[gwt-servlet.jar:na]
at com.google.web.bindery.requestfactory.server.RequestFactoryServlet.doPost(RequestFactoryServlet.java:133) ~[gwt-servlet.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647) [servlet-api.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) [servlet-api.jar:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.39.B]
at ch.qos.logback.access.servlet.TeeFilter.doFilter(TeeFilter.java:55) [logback-access-1.0.13.jar:na]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.39.B]
at org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:180) [spring-orm-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-3.2.2.RELEASE.jar:3.2.2.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.39.B]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:146) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:183) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:183) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160) [spring-security-web-3.1.4.RELEASE.jar:3.1.4.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) [spring-web-3.2.2.RELEASE.jar:3.2.2.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259) [spring-web-3.2.2.RELEASE.jar:3.2.2.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.39.B]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) [spring-web-3.2.2.RELEASE.jar:3.2.2.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-3.2.2.RELEASE.jar:3.2.2.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) [catalina.jar:7.0.39.B]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) [catalina.jar:7.0.39.B]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) [catalina.jar:7.0.39.B]
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947) [catalina.jar:7.0.39.B]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) [catalina.jar:7.0.39.B]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) [catalina.jar:7.0.39.B]
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009) [tomcat-coyote.jar:7.0.39.B]
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589) [tomcat-coyote.jar:7.0.39.B]
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312) [tomcat-coyote.jar:7.0.39.B]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_60]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_60]
at java.lang.Thread.run(Thread.java:745) [na:1.7.0_60]
最佳答案
我也遇到了这个异常并尝试了很多并提出了以下解决方法:
为您的类构建一个基本“底层”bean/POJO 模型,避免泛型(在最外面的类中,使用泛型似乎不是问题)并且可能使用一些“标记字符串”,如
_
帮助避免(通过“乐观的”接口(interface)使用)以后使用“不需要的类/方法”或提供所需的变体,例如:interface _Person< PERSON extends _Person<PERSON> > extends IsSerializable { // generics here: just to show that generics work if _Person is not // referenced itself in AutoBean (de)serialization int getId(); void setId( int id ); // normally we may not want to expose this, but for the // (de)serialization it is/may be necessary or benefitial // here now String getName(); void setName( String name ); //_Person setName_( String name ); // to have fluent setters is against Bean definition and does // not work with AutoBeans, but since there is no getter // "getName()" it is ignored and would work :-) // (but it may be better to not include it in here) _Address getAddr_(); void setAddr_( _Address addr ); } //interface _Address< ADDR extends _Address > extends IsSerializable { // => would e.g. cause the NullPointerException ! :-( // at com.google.web.bindery.autobean.vm.impl.MethodPropertyContext.traverse( // MethodPropertyContext.java:102) ~[gwt-user-2.6.0.jar:na] interface _Address extends IsSerializable { String getCity_(); void setCity_( String city ); }
- 现在将其与 AutoBean 功能一起使用将适用于这些功能,如果稍后使用通用接口(interface)和实现围绕这些功能应该可以工作(我只尝试了一个像这样的简单示例来为我测试它)。
上面的例子应该有效(不完整的片段):
AutoBeanCodex.encode( personAutoBean ).deepCopy()
- 现在将其与 AutoBean 功能一起使用将适用于这些功能,如果稍后使用通用接口(interface)和实现围绕这些功能应该可以工作(我只尝试了一个像这样的简单示例来为我测试它)。
上面的例子应该有效(不完整的片段):
现在创建通用接口(interface)和继承自这些接口(interface)的类会有缺点,例如不能
- 返回一个通用的
person.getAddr_().getNonBeanFooExtension()
或 - 使用像
person.setName_( "foo" ).setMail( "bar" )
这样的流畅界面或 - 阻止/阻止访问
person.setId( 123 )
因此,我现在正在计划(完成后我会报告)尽管如此,但也编写“不相关的继承”/重叠接口(interface),这些接口(interface)/应该在整个过程中“正常”使用业务应用,例如:
interface Person< PERSON extends Person<PERSON>> { // extends _Person <= no, because then we could not "hide/discourage" users calling // e.g. "setId(....)" int getId(); String getName(); //void setName( String name ); // we could provide it, but setName_() does the same // and more and only one setter keeps the interface // smaller PERSON setName_( String name ); Address<PERSON> getAddr(); PERSON setAddr( Address<PERSON> addr ); PERSON setFancyThing(); // not "seen" by AutoBean and thus should not // cause trouble there } interface Address< PERSON extends Person<PERSON> > { ... }
- 返回一个通用的
现在实现这样的类应该可以正常工作(目前只测试了简单的情况):
class PersonDTO implements Person<PersonDTO>, _Person<PersonDTO> { ... }
这些实现的“用户”应该尽可能多地使用来自 2 的接口(interface)。
Person<PersonDto> pers = ...
所以他们看到一些非常好的人机界面并且不能轻易地调用pers.setId( 123 )
,但是pers.setName_( "Dimitri Khalezov" ).setMail_( ... )
这已经是一篇很长的文章了,我希望你能想象到各个地方遗漏的细节。
关于java - RequestFactory:代理实现泛型接口(interface),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/24672800/