Spring 启动 REST 应用程序。 您不能将 bean 与 MVC 中的服务链接 controller
[英]Spring Boot REST App. You can't link bean with service in MVC controller
问题描述
下午好。 我是 Java 的新手，请耐心等待，我想通过 REST 获取实体列表。但我无法将 bean 与 MVC controller 中的服务链接起来。下面是我的代码。
资料库
public interface CustomerRepository extends JpaRepository<Customer, Long> {}
服务接口
public interface CustomerService {
Page<CustomerRsDto> getAll(Pageable pageable);
}
服务接口的实现
@Service
@RequiredArgsConstructor
public class CustomerServiceImpl implements CustomerService {
private final CustomerRepository customerRepository;
private final CustomerMapper customerMapper;
@Override
@Transactional
public Page<CustomerRsDto> getAll(Pageable pageable) {
List<Customer> dbCustomers = customerRepository.findAll();
List<CustomerRsDto> listCustomers = null;
dbCustomers.forEach(dbCustomer -> {
listCustomers.add(customerMapper.toRsDto(dbCustomer));
});
Page<CustomerRsDto> rsCustomers = new PageImpl<CustomerRsDto>(listCustomers);
return rsCustomers;
}
}
REST Controller
@RestController
@RequiredArgsConstructor
@RequestMapping("/customers")
@Api(tags = "customers", value = "Customres")
public class CustomersController {
private CustomerService customerService;
@GetMapping
@ApiOperation(tags = "customers", value = "Get all")
public Page<CustomerRsDto> getAll(Pageable pageable) {
if (isNull(customerService)) {
System.out.println("Not linked bean?");
}
return customerService.getAll(pageable);
}
}
这段代码可以编译，但是当我调用 curl controller 时，我收到一条消息，指出 bin 自动耦合没有发生，object 变量指向 null。
Curl 命令
curl -X GET "http://localhost:8080/customers?pageNumber=1&pageSize=5" -H "accept: */*" -H 'authorization: Basic YWRtaW46YWRtaW4='
来自 servlet 容器的消息
2020-11-12 14:30:19.958 INFO 7836 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 5 ms
Not linked bean?
2020-11-12 14:30:20.407 ERROR 7836 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
at <My Packages>.rest.CustomersController.getAll(CustomersController.java:31) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.39.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.39.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:118) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:158) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:204) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.ui.DefaultLogoutPageGeneratingFilter.doFilterInternal(DefaultLogoutPageGeneratingFilter.java:52) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:216) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:92) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:77) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.3.5.RELEASE.jar:5.3.5.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.10.RELEASE.jar:5.2.10.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.keycloak.adapters.tomcat.AbstractAuthenticatedActionsValve.invoke(AbstractAuthenticatedActionsValve.java:67) ~[spring-boot-container-bundle-10.0.2.jar:10.0.2]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.keycloak.adapters.tomcat.AbstractKeycloakAuthenticatorValve.invoke(AbstractKeycloakAuthenticatorValve.java:181) ~[spring-boot-container-bundle-10.0.2.jar:10.0.2]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.39.jar:9.0.39]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
我的错误在哪里？ 感谢所有回复此帖子的人！
1 个解决方案
解决方案1
1 已采纳 2020-11-12 12:21:04
如果你想让 Spring 给你注入 bean，你必须：
- 将
@Autowired添加到该字段 - 将
@Autowired添加到该字段的设置器 - 提供构造函数参数（并可选择将
@Autowired添加到构造函数）
在您的情况下，您将 Lombok 与@RequiredArgsConstructor一起使用，它将所有最终字段添加到构造函数，但字段 customerService 不是最终的。
这是您的 REST controller 的正确实现：
@RestController
@RequiredArgsConstructor
@RequestMapping("/customers")
@Api(tags = "customers", value = "Customres")
public class CustomersController {
private final CustomerService customerService;
@GetMapping
@ApiOperation(tags = "customers", value = "Get all")
public Page<CustomerRsDto> getAll(Pageable pageable) {
if (isNull(customerService)) {
System.out.println("Not linked bean?");
}
return customerService.getAll(pageable);
}
}
另一个提示（不直接涉及此问题）：在您的存储库中使用带有Pageable参数的findAll方法，如下所示：
@Service
@RequiredArgsConstructor
public class CustomerServiceImpl implements CustomerService {
private final CustomerRepository customerRepository;
private final CustomerMapper customerMapper;
@Override
@Transactional
public Page<CustomerRsDto> getAll(Pageable pageable) {
Page<Customer> dbCustomers = customerRepository.findAll(pageable);
return dbCustomers.map(dbCustomer -> customerMapper.toRsDto(dbCustomer));
}
}
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