1、簡介

SpringBoot不僅繼承了Spring框架原有的優秀特性，而且還通過簡化配置來進一步簡化了Spring應用的整個搭建和開發過程。在Spring-Boot項目開發中，存在著本模塊的代碼需要訪問外面模塊接口，或外部url鏈接的需求, 比如在apaas開發過程中需要封裝接口在接口中調用apaas提供的接口（像發起流程接口submit等等）下面也是提供了三種方式（不使用dubbo的方式）供我們選擇

2、方式一：使用原始httpClient請求

/*
?*?@description?get方式獲取入參，插入數據并發起流程
?*?@author?lyx
?*?@date?2022/8/24?16:05
?*?@params?documentId
?*?@return?String
?*/
//
@RequestMapping("/submit/{documentId}")
public?String?submit1(@PathVariable?String?documentId)?throws?ParseException?{
????//此處將要發送的數據轉換為json格式字符串
????Map?map?=task2Service.getMap(documentId);
????String?jsonStr?=?JSON.toJSONString(map,?SerializerFeature.WRITE_MAP_NULL_FEATURES,SerializerFeature.QuoteFieldNames);
????JSONObject?jsonObject?=?JSON.parseObject(jsonStr);
????JSONObject?sr?=?task2Service.doPost(jsonObject);
????return?sr.toString();
}

/*
?*?@description?使用原生httpClient調用外部接口
?*?@author?lyx
?*?@date?2022/8/24?16:08
?*?@params?date
?*?@return?JSONObject
?*/
public?static?JSONObject?doPost(JSONObject?date)?{
????String?assessToken="eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ4ZGFwYXBwaWQiOiIzNDgxMjU4ODk2OTI2OTY1NzYiLCJleHAiOjE2NjEyMjY5MDgsImlhdCI6MTY2MTIxOTcwOCwieGRhcHRlbmFudGlkIjoiMzAwOTgxNjA1MTE0MDUyNjA5IiwieGRhcHVzZXJpZCI6IjEwMDM0NzY2MzU4MzM1OTc5NTIwMCJ9.fZAO4kJSv2rSH0RBiL1zghdko8Npmu_9ufo6Wex_TI2q9gsiLp7XaW7U9Cu7uewEOaX4DTdpbFmMPvLUtcj_sQ";
????CloseableHttpClient?client?=?HttpClients.createDefault();
????//?要調用的接口url
????String?url?=?"http://39.103.201.110:30661?/xdap-open/open/process/v1/submit";
????HttpPost?post?=?new?HttpPost(url);
????JSONObject?jsonObject?=?null;
????try?{
????????//創建請求體并添加數據
????????StringEntity?s?=?new?StringEntity(date.toString());
????????//此處相當于在header里頭添加content-type等參數
????????s.setContentType("application/json");
????????s.setContentEncoding("UTF-8");
????????post.setEntity(s);
????????//此處相當于在Authorization里頭添加Bear?token參數信息
????????post.addHeader("Authorization",?"Bearer?"?+assessToken);
????????HttpResponse?res?=?client.execute(post);
????????String?response1?=?EntityUtils.toString(res.getEntity());
????????if?(res.getStatusLine()
????????????????.getStatusCode()?==?HttpStatus.SC_OK)?{
????????????//?返回json格式：
????????????String?result?=?EntityUtils.toString(res.getEntity());
????????????jsonObject?=?JSONObject.parseObject(result);
????????}
????}?catch?(Exception?e)?{
????????throw?new?RuntimeException(e);
????}
????return?jsonObject;
}

3、方式二：使用RestTemplate方法

Spring-Boot開發中，RestTemplate同樣提供了對外訪問的接口API，這里主要介紹Get和Post方法的使用。

Get請求

提供了getForObject 、getForEntity兩種方式，其中getForEntity如下三種方法的實現：

Get--getForEntity，存在以下兩種方式重載

1.getForEntity(Stringurl,Class?responseType,Object…urlVariables)
2.getForEntity(URI?url,Class?responseType)

Get--getForEntity(URI url,Class responseType)

//該方法使用URI對象來替代之前的url和urlVariables參數來指定訪問地址和參數綁定。URI是JDK java.net包下的一個類，表示一個統一資源標識符(Uniform Resource Identifier)引用。參考如下：
RestTemplate?restTemplate=new?RestTemplate();
UriComponents?
uriComponents=UriComponentsBuilder.fromUriString("http://USER-SERVICE/user?name={name}")
.build()
.expand("dodo")
.encode();
URI?uri=uriComponents.toUri();
ResponseEntityresponseEntity=restTemplate.getForEntity(uri,String.class).getBody();

Get--getForEntity(Stringurl,Class responseType,Object…urlVariables)

//該方法提供了三個參數，其中url為請求的地址，responseType為請求響應body的包裝類型，urlVariables為url中的參數綁定，該方法的參考調用如下：
//?http://USER-SERVICE/user?name={name)
RestTemplate?restTemplate=new?RestTemplate();
Mapparams=new?HashMap<>();
params.put("name","dada");?//
ResponseEntityresponseEntity=restTemplate.getForEntity("http://USERSERVICE/user?name={name}",String.class,params);

Get--getForObject，存在以下三種方式重載

1.getForObject(String?url,Class?responseType,Object...urlVariables)
2.getForObject(String?url,Class?responseType,Map?urlVariables)
3.getForObject(URI?url,Class?responseType)

getForObject方法可以理解為對getForEntity的進一步封裝，它通過HttpMessageConverterExtractor對HTTP的請求響應體body內容進行對象轉換，實現請求直接返回包裝好的對象內容。

Post 請求

Post請求提供有postForEntity、postForObject和postForLocation三種方式，其中每種方式都有三種方法，下面介紹postForEntity的使用方法。

Post--postForEntity，存在以下三種方式重載

1.postForEntity(String?url,Object?request,Class?responseType,Object...??uriVariables)?
2.postForEntity(String?url,Object?request,Class?responseType,Map??uriVariables)?
3.postForEntity(URI?url,Object?request，Class?responseType)

如下僅演示第二種重載方式

/*
?*?@description?post方式獲取入參，插入數據并發起流程
?*?@author?lyx
?*?@date?2022/8/24?16:07
?*?@params
?*?@return
?*/
@PostMapping("/submit2")
public?Object?insertFinanceCompensation(@RequestBody?JSONObject?jsonObject)?{
????String?documentId=jsonObject.get("documentId").toString();
????return?task2Service.submit(documentId);
}

/*
?*?@description?使用restTimeplate調外部接口
?*?@author?lyx
?*?@date?2022/8/24?16:02
?*?@params?documentId
?*?@return?String
?*/
public?String?submit(String?documentId){
????String?assessToken="eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ4ZGFwYXBwaWQiOiIzNDgxMjU4ODk2OTI2OTY1NzYiLCJleHAiOjE2NjEyMjY5MDgsImlhdCI6MTY2MTIxOTcwOCwieGRhcHRlbmFudGlkIjoiMzAwOTgxNjA1MTE0MDUyNjA5IiwieGRhcHVzZXJpZCI6IjEwMDM0NzY2MzU4MzM1OTc5NTIwMCJ9.fZAO4kJSv2rSH0RBiL1zghdko8Npmu_9ufo6Wex_TI2q9gsiLp7XaW7U9Cu7uewEOaX4DTdpbFmMPvLUtcj_sQ";
????RestTemplate?restTemplate?=?new?RestTemplate();
????//創建請求頭
????HttpHeaders?httpHeaders?=?new?HttpHeaders();
????//此處相當于在Authorization里頭添加Bear?token參數信息
????httpHeaders.add(HttpHeaders.AUTHORIZATION,?"Bearer?"?+?assessToken);
????//此處相當于在header里頭添加content-type等參數
????httpHeaders.add(HttpHeaders.CONTENT_TYPE,"application/json");
????Map?map?=?getMap(documentId);
????String?jsonStr?=?JSON.toJSONString(map);
????//創建請求體并添加數據
????HttpEntity

4、方式三：使用Feign進行消費

在maven項目中添加依賴

????org.springframework.cloud
????spring-cloud-starter-feign
????1.2.2.RELEASE

啟動類上加上@EnableFeignClients

@SpringBootApplication
@EnableFeignClients
@ComponentScan(basePackages?=?{"com.definesys.mpaas",?"com.xdap.*"?,"com.xdap.*"})
public?class?MobilecardApplication?{
?
????public?static?void?main(String[]?args)?{
????????SpringApplication.run(MobilecardApplication.class,?args);
????}
?
}

此處編寫接口模擬外部接口供feign調用外部接口方式使用

定義controller

@Autowired
PrintService?printService;

@PostMapping("/outSide")
public?String?test(@RequestBody?TestDto?testDto)?{
????return?printService.print(testDto);
}

定義service

@Service
public?interface?PrintService?{
????public?String?print(TestDto?testDto);
}
定義serviceImpl

public?class?PrintServiceImpl?implements?PrintService?{
?
????@Override
????public?String?print(TestDto?testDto)?{
????????return?"模擬外部系統的接口功能"+testDto.getId();
????}
}

構建Feigin的Service

定義service

//此處name需要設置不為空，url需要在.properties中設置
@Service
@FeignClient(url?=?"${outSide.url}",?name?=?"service2")
public?interface?FeignService2?{
????@RequestMapping(value?=?"/custom/outSide",?method?=?RequestMethod.POST)
????@ResponseBody
????public?String?getMessage(@Valid?@RequestBody?TestDto?testDto);
}

定義controller

@Autowired
FeignService2?feignService2;
//測試feign調用外部接口入口
@PostMapping("/test2")
public?String?test2(@RequestBody?TestDto?testDto)?{
????return?feignService2.getMessage(testDto);
}

postman測試

此處因為我使用了所在項目，所以需要添加一定的請求頭等信息，關于Feign的請求頭添加也會在后續補充

補充如下：

添加Header解決方法

將token等信息放入Feign請求頭中，主要通過重寫RequestInterceptor的apply方法實現

定義config

@Configuration
public?class?FeignConfig?implements?RequestInterceptor?{
????@Override
????public?void?apply(RequestTemplate?requestTemplate)?{
????????//添加token
????????requestTemplate.header("token",?"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ4ZGFwYXBwaWQiOiIzNDgxMjU4ODk2OTI2OTY1NzYiLCJleHAiOjE2NjEyMjY5MDgsImlhdCI6MTY2MTIxOTcwOCwieGRhcHRlbmFudGlkIjoiMzAwOTgxNjA1MTE0MDUyNjA5IiwieGRhcHVzZXJpZCI6IjEwMDM0NzY2MzU4MzM1OTc5NTIwMCJ9.fZAO4kJSv2rSH0RBiL1zghdko8Npmu_9ufo6Wex_TI2q9gsiLp7XaW7U9Cu7uewEOaX4DTdpbFmMPvLUtcj_sQ");
????}
}

定義service

@Service
@FeignClient(url?=?"${outSide.url}",name?=?"feignServer",?configuration?=?FeignDemoConfig.class)
public?interface?TokenDemoClient?{
????@RequestMapping(value?=?"/custom/outSideAddToken",?method?=?RequestMethod.POST)
????@ResponseBody
????public?String?getMessage(@Valid?@RequestBody?TestDto?testDto);
}
定義controller

//測試feign調用外部接口入口，加上token
@PostMapping("/testToken")
public?String?test4(@RequestBody?TestDto?testDto)?{
????return?tokenDemoClient.getMessage(testDto);
}
編輯：黃飛

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