从 Java 8 函数创建请求范围的 bean
Create request scoped beans from a Java 8 Function
基于this answer我尝试使用java.util.Function
接口配置请求范围bean。
我的配置如下所示:
@Configuration
public class RequestConfig {
@Bean
public Function<? extends BaseRequest, RequestWrapper<? extends BaseRequest, ? extends BaseResponse>> requestWrapperFactory() {
return request -> requestWrapper(request);
}
@Bean
@RequestScope
public RequestWrapper<? extends BaseRequest, ? extends BaseResponse> requestWrapper(
BaseRequest request) {
RequestWrapper<?, ?> requestWrapper = new RequestWrapper<BaseRequest, BaseResponse>(request);
return requestWrapper;
}
}
我尝试像这样使用 bean:
@RestController
public class CheckRequestController {
private final RequestService<CheckRequest, CheckResponse> checkRequestServiceImpl;
@Autowired
private Function<CheckRequest, RequestWrapper<CheckRequest, CheckResponse>> requestWrapperFactory;
public CheckRequestController(
RequestService<CheckRequest, CheckResponse> checkRequestServiceImpl) {
super();
this.checkRequestServiceImpl = checkRequestServiceImpl;
}
@PostMapping(value = "/check", consumes = { MediaType.TEXT_XML_VALUE,
MediaType.MULTIPART_FORM_DATA_VALUE }, produces = MediaType.TEXT_XML_VALUE)
public ResponseEntity<CheckResponse> checkRequest(
@RequestBody(required = true) CheckRequest checkRequest) {
RequestWrapper<CheckRequest, CheckResponse> requestWrapper = requestWrapperFactory
.apply(checkRequest);
checkRequestServiceImpl.getResponse(requestWrapper);
return new ResponseEntity<CheckResponse>(requestWrapper.getResponse(),
HttpStatus.OK);
}
}
这里:
@RestController
public class CancelRequestController {
private final RequestService<CancelRequest, CancelResponse> cancelRequestServiceImpl;
@Autowired
private Function<CancelRequest, RequestWrapper<CancelRequest, CancelResponse>> requestWrapperFactory;
public CancelRequestController(
RequestService<CancelRequest, CancelResponse> cancelRequestServiceImpl) {
super();
this.cancelRequestServiceImpl = cancelRequestServiceImpl;
}
@PostMapping(value = "/cancel", consumes = { MediaType.TEXT_XML_VALUE,
MediaType.MULTIPART_FORM_DATA_VALUE }, produces = MediaType.TEXT_XML_VALUE)
public ResponseEntity<CancelResponse> CancelRequest(
@RequestBody(required = true) CancelRequest cancelRequest) {
RequestWrapper<CancelRequest, CancelResponse> requestWrapper = requestWrapperFactory
.apply(cancelRequest);
cancelRequestServiceImpl.getResponse(requestWrapper);
return new ResponseEntity<CancelResponse>(requestWrapper.getResponse(),
HttpStatus.OK);
}
}
但是我发现没有定义 Function
类型的 bean。
Field requestWrapperFactory in CheckRequestController required a bean of type 'java.util.Function' that could not be found.
The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)
Action:
Consider defining a bean of type 'java.util.Function' in your configuration.
使用泛型有问题吗?我做错了什么?
您提到的答案有所不同:它在声明的 bean 和注入的 bean 中使用完全相同的泛型类型:
@Bean
public Function<String, Thing> thingFactory() {
return name -> thing(name); // or this::thing
}
和:
@Autowired
private Function<String, Thing> thingFactory;
Is there a problem by using generic types? What do I wrong?
是的。你想用这个签名注入一个 bean :
Function<CheckRequest, RequestWrapper<CheckRequest, CheckResponse>> requestWrapperFactory;
但是你用这个签名声明了一个 bean :
Function<? extends BaseRequest, RequestWrapper<? extends BaseRequest, ? extends BaseResponse>>
此处:
@Bean
public Function<? extends BaseRequest, RequestWrapper<? extends BaseRequest, ? extends BaseResponse>> requestWrapperFactory() {
return request -> requestWrapper(request);
}
bean 声明中使用的泛型和连接的 bean 必须相同才能在依赖注入方面匹配。
所以只要在两边声明相同的类型即可。
so this means there is no way to configure a bean using generics?
because I wanted to use the bean creation also for CancelRequest
(updated answer). So I have to create a Bean for all types of
BaseRequest..
对于 @RequestScope
bean,理论上使用泛型不会产生任何问题,因为 bean 是在每次请求时创建的,不会重复使用,但我认为 @Bean
的通用特性不会' t 造成这种差异,因此考虑一般情况(单例范围),在这种情况下需要完美匹配以避免类型安全和一致性问题。 It could interest you。
编辑后:
我更新了第一部分以与您的更改保持一致。
现在您的要求是向客户端声明一个函数,该函数 returns 具有客户端指定的通用类型的原型 bean。
这是可能的。但是为了让它整洁,你不应该使用两个 beans:一个用于工厂(单例),另一个用于创建 RequestWrapper
对象(原型)。
由于工厂 bean 不允许客户指定通用类型,因此您将不得不执行不需要的取消转换。
您还应该将 @RequestScope
替换为 @Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
,因为请求范围的 bean 不允许在配置 class.
中像单例和原型 bean 一样多的可配置性
例如,使用参数或通配符效果不佳。
所以这个想法是声明一个原型 bean,其返回的泛型类型取决于参数和目标。
关于RequestConfig
,现在最好命名为RequestFactory
,因为这是它的作用。
@Configuration
public class RequestFactory {
@Bean
@Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public <T extends BaseRequest, U extends BaseResponse> RequestWrapper<T, U> requestWrapper(
T request) {
RequestWrapper<T, U> requestWrapper = new RequestWrapper<>(request);
return requestWrapper;
}
}
在控制器中注入 @Configuration
bean requestFactory
:
private RequestFactory requestFactory; // Change
public CheckRequestController(
RequestService<CheckRequest, CheckResponse> checkRequestServiceImpl,
RequestConfig requestConfig) {
this.checkRequestServiceImpl = checkRequestServiceImpl;
this.requestFactory = requestFactory; // Change
}
现在您可以在需要时注入具有所需 RequestWrapper
的原型 bean:
@PostMapping(value = "/cancel", consumes = { MediaType.TEXT_XML_VALUE,
MediaType.MULTIPART_FORM_DATA_VALUE }, produces = MediaType.TEXT_XML_VALUE)
public ResponseEntity<CancelResponse> CancelRequest(
@RequestBody(required = true) CancelRequest cancelRequest) {
RequestWrapper<CheckRequest, CheckResponse> requestWrapper =
requestFactory.requestWrapper(cancelRequest);
//...
return new ResponseEntity<CancelResponse>(requestWrapper.getResponse(),
HttpStatus.OK);
}
现在已经测试过了,它看起来可以工作。
基于this answer我尝试使用java.util.Function
接口配置请求范围bean。
我的配置如下所示:
@Configuration
public class RequestConfig {
@Bean
public Function<? extends BaseRequest, RequestWrapper<? extends BaseRequest, ? extends BaseResponse>> requestWrapperFactory() {
return request -> requestWrapper(request);
}
@Bean
@RequestScope
public RequestWrapper<? extends BaseRequest, ? extends BaseResponse> requestWrapper(
BaseRequest request) {
RequestWrapper<?, ?> requestWrapper = new RequestWrapper<BaseRequest, BaseResponse>(request);
return requestWrapper;
}
}
我尝试像这样使用 bean:
@RestController
public class CheckRequestController {
private final RequestService<CheckRequest, CheckResponse> checkRequestServiceImpl;
@Autowired
private Function<CheckRequest, RequestWrapper<CheckRequest, CheckResponse>> requestWrapperFactory;
public CheckRequestController(
RequestService<CheckRequest, CheckResponse> checkRequestServiceImpl) {
super();
this.checkRequestServiceImpl = checkRequestServiceImpl;
}
@PostMapping(value = "/check", consumes = { MediaType.TEXT_XML_VALUE,
MediaType.MULTIPART_FORM_DATA_VALUE }, produces = MediaType.TEXT_XML_VALUE)
public ResponseEntity<CheckResponse> checkRequest(
@RequestBody(required = true) CheckRequest checkRequest) {
RequestWrapper<CheckRequest, CheckResponse> requestWrapper = requestWrapperFactory
.apply(checkRequest);
checkRequestServiceImpl.getResponse(requestWrapper);
return new ResponseEntity<CheckResponse>(requestWrapper.getResponse(),
HttpStatus.OK);
}
}
这里:
@RestController
public class CancelRequestController {
private final RequestService<CancelRequest, CancelResponse> cancelRequestServiceImpl;
@Autowired
private Function<CancelRequest, RequestWrapper<CancelRequest, CancelResponse>> requestWrapperFactory;
public CancelRequestController(
RequestService<CancelRequest, CancelResponse> cancelRequestServiceImpl) {
super();
this.cancelRequestServiceImpl = cancelRequestServiceImpl;
}
@PostMapping(value = "/cancel", consumes = { MediaType.TEXT_XML_VALUE,
MediaType.MULTIPART_FORM_DATA_VALUE }, produces = MediaType.TEXT_XML_VALUE)
public ResponseEntity<CancelResponse> CancelRequest(
@RequestBody(required = true) CancelRequest cancelRequest) {
RequestWrapper<CancelRequest, CancelResponse> requestWrapper = requestWrapperFactory
.apply(cancelRequest);
cancelRequestServiceImpl.getResponse(requestWrapper);
return new ResponseEntity<CancelResponse>(requestWrapper.getResponse(),
HttpStatus.OK);
}
}
但是我发现没有定义 Function
类型的 bean。
Field requestWrapperFactory in CheckRequestController required a bean of type 'java.util.Function' that could not be found.
The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)
Action:
Consider defining a bean of type 'java.util.Function' in your configuration.
使用泛型有问题吗?我做错了什么?
您提到的答案有所不同:它在声明的 bean 和注入的 bean 中使用完全相同的泛型类型:
@Bean
public Function<String, Thing> thingFactory() {
return name -> thing(name); // or this::thing
}
和:
@Autowired
private Function<String, Thing> thingFactory;
Is there a problem by using generic types? What do I wrong?
是的。你想用这个签名注入一个 bean :
Function<CheckRequest, RequestWrapper<CheckRequest, CheckResponse>> requestWrapperFactory;
但是你用这个签名声明了一个 bean :
Function<? extends BaseRequest, RequestWrapper<? extends BaseRequest, ? extends BaseResponse>>
此处:
@Bean
public Function<? extends BaseRequest, RequestWrapper<? extends BaseRequest, ? extends BaseResponse>> requestWrapperFactory() {
return request -> requestWrapper(request);
}
bean 声明中使用的泛型和连接的 bean 必须相同才能在依赖注入方面匹配。
所以只要在两边声明相同的类型即可。
so this means there is no way to configure a bean using generics? because I wanted to use the bean creation also for CancelRequest (updated answer). So I have to create a Bean for all types of BaseRequest..
对于 @RequestScope
bean,理论上使用泛型不会产生任何问题,因为 bean 是在每次请求时创建的,不会重复使用,但我认为 @Bean
的通用特性不会' t 造成这种差异,因此考虑一般情况(单例范围),在这种情况下需要完美匹配以避免类型安全和一致性问题。 It could interest you。
编辑后:
我更新了第一部分以与您的更改保持一致。
现在您的要求是向客户端声明一个函数,该函数 returns 具有客户端指定的通用类型的原型 bean。
这是可能的。但是为了让它整洁,你不应该使用两个 beans:一个用于工厂(单例),另一个用于创建 RequestWrapper
对象(原型)。
由于工厂 bean 不允许客户指定通用类型,因此您将不得不执行不需要的取消转换。
您还应该将 @RequestScope
替换为 @Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
,因为请求范围的 bean 不允许在配置 class.
中像单例和原型 bean 一样多的可配置性
例如,使用参数或通配符效果不佳。
所以这个想法是声明一个原型 bean,其返回的泛型类型取决于参数和目标。
关于RequestConfig
,现在最好命名为RequestFactory
,因为这是它的作用。
@Configuration
public class RequestFactory {
@Bean
@Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public <T extends BaseRequest, U extends BaseResponse> RequestWrapper<T, U> requestWrapper(
T request) {
RequestWrapper<T, U> requestWrapper = new RequestWrapper<>(request);
return requestWrapper;
}
}
在控制器中注入 @Configuration
bean requestFactory
:
private RequestFactory requestFactory; // Change
public CheckRequestController(
RequestService<CheckRequest, CheckResponse> checkRequestServiceImpl,
RequestConfig requestConfig) {
this.checkRequestServiceImpl = checkRequestServiceImpl;
this.requestFactory = requestFactory; // Change
}
现在您可以在需要时注入具有所需 RequestWrapper
的原型 bean:
@PostMapping(value = "/cancel", consumes = { MediaType.TEXT_XML_VALUE,
MediaType.MULTIPART_FORM_DATA_VALUE }, produces = MediaType.TEXT_XML_VALUE)
public ResponseEntity<CancelResponse> CancelRequest(
@RequestBody(required = true) CancelRequest cancelRequest) {
RequestWrapper<CheckRequest, CheckResponse> requestWrapper =
requestFactory.requestWrapper(cancelRequest);
//...
return new ResponseEntity<CancelResponse>(requestWrapper.getResponse(),
HttpStatus.OK);
}
现在已经测试过了,它看起来可以工作。