動力節(jié)點SpringBoot3第六章

動力節(jié)點SpringBoot3第六章6

遠程訪問@HttpExchange[SpringBoot3]遠程訪問是開發(fā)的常用技術(shù)，一個應(yīng)用能夠訪問其他應(yīng)用的功能。SpringBoot提供了多種遠程訪問的技術(shù)?；贖TTP協(xié)議的遠程訪問是支付最廣泛的。SpringBoot3提供了新的HTTP的訪問能力，通過接口簡化HTTP遠程訪問，類似Feign功能。Spring包裝了底層HTTP客戶的訪問細節(jié)。SpringBoot中定義接口提供HTTP服務(wù)。生成的代理對象實現(xiàn)此接口，代理對象實現(xiàn)HTTP的遠程訪問。需要理解：@HttpExchangeWebClientWebClient特性：我們想要調(diào)用其他系統(tǒng)提供的HTTP服務(wù)，通?？梢允褂肧pring提供的RestTemplate來訪問，RestTemplate是Spring3中引入的同步阻塞式HTTP客戶端，因此存在一定性能瓶頸。Spring官方在Spring5中引入了WebClient作為非阻塞式HTTP客戶端。非阻塞，異步請求它的響應(yīng)式編程的基于Reactor高并發(fā)，硬件資源少。支持Java8lambdas函數(shù)式編程什么是異步非阻塞理解：異步和同步，非阻塞和阻塞上面都是針對對象不一樣異步和同步針對調(diào)度者,調(diào)用者發(fā)送請求,如果等待對方回應(yīng)之后才去做其他事情,就是同步,如果發(fā)送請求之后不等著對方回應(yīng)就去做其他事情就是異步阻塞和非阻塞針對被調(diào)度者,被調(diào)度者收到請求后,做完請求任務(wù)之后才給出反饋就是阻塞,收到請求之后馬上給出反饋然后去做事情,就是非阻塞6.1

準備工作：1.安裝GsonFormat插件，方便json和Bean的轉(zhuǎn)換2.介紹一個免費的、24h在線的RestHttp服務(wù)，每月提供近20億的請求，關(guān)鍵還是免費的、可公開訪問的。/6.1.1

聲明式HTTP遠程服務(wù)需求：訪問/

提供的todos服務(wù)?；赗ESTful風(fēng)格，添加新的todo，修改todo，修改todo中的title，查詢某個todo。聲明接口提供對象/todos服務(wù)的訪問創(chuàng)建新的SpringBoot項目Lession18-HttpService,Maven構(gòu)建工具，JDK19。SpringWeb,SpringReactiveWeb,Lombok依賴。包名稱：com.bjpowernode.httpstep1：Maven依賴pom.xml|org.springframework.bootspring-boot-starter-weborg.springframework.bootspring-boot-starter-webfluxstep2:聲明Todo數(shù)據(jù)類|/**根據(jù)/todos/1的結(jié)構(gòu)創(chuàng)建的*/publicclassTodo{privateintuserId;privateintid;privateStringtitle;privatebooleancompleted;//省略set，get方法publicbooleangetCompleted(){returncompleted;}publicvoidsetCompleted(booleancompleted){pleted=completed;}@OverridepublicStringtoString(){return"Todo{"+"userId="+userId+",id="+id+",title='"+title+'\''+",completed="+completed+'}';}}||---|step3:聲明服務(wù)接口|importorg.springframework.http.HttpHeaders;importorg.springframework.http.MediaType;importorg.springframework.http.ResponseEntity;//...publicinterfaceTodoService{@GetExchange("/todos/{id}")TodogetTodoById(@PathVariableIntegerid);@PostExchange(value="/todos",accept=MediaType.APPLICATION_JSON_VALUE)TodocreateTodo(@RequestBody

TodonewTodo);@PutExchange("/todos/{id}")ResponseEntitymodifyTodo(@PathVariableIntegerid,@RequestBodyTodotodo);@PatchExchange("/todos/{id}")HttpHeaderspathRequest(@PathVariableIntegerid,@RequestParamStringtitle);@DeleteExchange("/todos/{id}")voidremoveTodo(@PathVariableIntegerid);}step4:創(chuàng)建HTTP服務(wù)代理對象|@Configuration(proxyBeanMethods=false)publicclassHttpConfiguration{@BeanpublicTodoServicerequestService(){WebClientwebClient=WebClient.builder().baseUrl("/").build();HttpServiceProxyFactoryproxyFactory=HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient)).build();returnproxyFactory.createClient(TodoService.class);}}step5:單元測試|@SpringBootTestclassHttpApplicationTests{@ResourceprivateTodoServicerequestService;@TestvoidtestQuery(){Todotodo=requestService.getTodoById(1);System.out.println("todo="+todo);}@TestvoidtestCreateTodo(){Todotodo=newTodo();todo.setId(1001);todo.setCompleted(true);todo.setTitle("錄制視頻");todo.setUserId(5001);Todosave=requestService.createTodo(todo);System.out.println(save);}@TestvoidtestModifyTitle(){//org.springframework.http.HttpHeadersHttpHeadersentries=requestService.pathRequest(5,"homework");entries.forEach((name,vals)->{System.out.println(name);vals.forEach(System.out::println);System.out.println("=========================");});}@TestvoidtestModifyTodo(){Todotodo=newTodo();todo.setCompleted(true);todo.setTitle("錄制視頻!!!");todo.setUserId(5002);ResponseEntityresult=requestService.modifyTodo(2,todo);HttpStatusCodestatusCode=result.getStatusCode();HttpHeadersheaders=result.getHeaders();TodomodifyTodo=result.getBody();System.out.println("statusCode="+statusCode);System.out.println("headers="+headers);System.out.println("modifyTodo="+modifyTodo);}@TestvoidtestRemove(){requestService.removeTodo(2);}}

Http服務(wù)接口的方法定義@HttpExchange注解用于聲明接口作為HTTP遠程服務(wù)。在方法、類級別使用。通過注解屬性以及方法的參數(shù)設(shè)置HTTP請求的細節(jié)?？旖葑⒔夂喕煌恼埱蠓绞紾etExchangePostExchangePutExchangePatchExchangeDeleteExchange@GetExchange就是@HttpExchange表示的GET請求方式|@HttpExchange(method="GET")public@interfaceGetExchange{@AliasFor(annotation=HttpExchange.class)Stringvalue()default"";@AliasFor(annotation=HttpExchange.class)Stringurl()default"";@AliasFor(annotation=HttpExchange.class)String[]accept()default{};}作為HTTP服務(wù)接口中的方法允許使用的參數(shù)列表參數(shù)說明URI設(shè)置請求的url，覆蓋注解的url屬性HttpMethod請求方式，覆蓋注解的method屬性@RequestHeader添加到請求中header。參數(shù)類型可以為Map<String,?>,MultiValueMap<String,?>,單個值或者Collection<?>@PathVariableurl中的占位符，參數(shù)可為單個值或Map<String,?>@RequestBody請求體，參數(shù)是對象@RequestParam請求參數(shù)，單個值或Map<String,?>,MultiValueMap<String,?>，Collection<?>@RequestPart發(fā)送文件時使用@CookieValue向請求中添加cookie接口中方法返回值返回值類型說明void執(zhí)行請求，無需解析應(yīng)答HttpHeaders存儲response應(yīng)答的header信息對象解析應(yīng)答結(jié)果，轉(zhuǎn)為聲明的類型對象ResponseEntity，ResponseEntity解析應(yīng)答內(nèi)容，得到ResponseEntity,從ResponseEntity可以獲取http應(yīng)答碼，header，body內(nèi)容。反應(yīng)式的相關(guān)的返回值包含Mono,Mono,Mono,FluxMono<ResponseEntity>,Mono<ResponseEntity>,Mono<ResponseEntity<Flux>。

組合使用注解@HttpExchange，@GetExchange等可以組合使用。這次使用Albums遠程服務(wù)接口，查詢Albums信息step1:創(chuàng)建Albums數(shù)據(jù)類|publicclassAlbums{privateintuserId;privateintid;privateStringtitle;//省略set,get@OverridepublicStringtoString(){return"Albums{"+"userId="+userId+",id="+id+",title='"+title+'\''+'}';}}step2:創(chuàng)建AlbumsService接口接口聲明方法，提供HTTP遠程服務(wù)。在類級別應(yīng)用@HttpExchange接口，在方法級別使用@HttpExchange,@GetExchange等|@HttpExchange(url="/")publicinterfaceAlbumsService{@GetExchange("/albums/{aid}")AlbumsgetById(@PathVariableIntegeraid);@HttpExchange(url="/albums/{aid}",method=

"GET",contentType=MediaType.APPLICATION_JSON_VALUE)AlbumsgetByIdV2(@PathVariableIntegeraid);}類級別的url和方法級別的url組合在一起為最后的請求url地址。step3:聲明代理|@Configuration(proxyBeanMethods=true)publicclassHttpServiceConfiguration{@BeanpublicAlbumsServicealbumsService(){WebClientwebClient=WebClient.create();HttpServiceProxyFactoryproxyFactory=HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient)).build();returnproxyFactory.createClient(AlbumsService.class);}}step4:單元測試|@SpringBootTestpublicclassTestHttpExchange{@ResourceAlbumsServicealbumsService;@TestvoidgetQuery(){Albumsalbums=albumsService.getById(1);System.out.println("albums="+albums);}@TestvoidgetQueryV2(){Albumsalbums=albumsService.getByIdV2(2);System.out.println("albums="+albums);}}測試方法能正常完成遠程方法調(diào)用。

JavaRecord測試JavaRecord作為返回類型，由框架的HTTP代理轉(zhuǎn)換應(yīng)該內(nèi)容為Record對象step1:創(chuàng)建Albums的JavaRecord|publicrecordAlbumsRecord(intuserId,intid,Stringtitle){}step2:AlbumsService接口增加新的遠程訪問方法，方法返回類型為Record|@GetExchange("/albums/{aid}")AlbumsRecordgetByIdRecord(@PathVariableIntegeraid);step3:單元測試，Record接收結(jié)果|@TestvoidgetQueryV3(){AlbumsRecordalbums=albumsService.getByIdRecord(1);System.out.println("albums="+albums);}JavaRecord能夠正確接收應(yīng)該結(jié)果，轉(zhuǎn)為AlbumsRecord對象。

定制HTTP請求服務(wù)設(shè)置HTTP遠程的超時時間，異常處理在創(chuàng)建接口代理對象前，先設(shè)置WebClient的有關(guān)配置。step1:設(shè)置超時，異常處理|

@BeanpublicAlb