SpringBoot使用RestTemplate實(shí)現(xiàn)HTTP請(qǐng)求詳解

更新時(shí)間：2024年03月21日 08:21:49 作者：一線大碼

這篇文章主要為大家詳細(xì)介紹了SpringBoot如何使用RestTemplate實(shí)現(xiàn)進(jìn)行HTTP請(qǐng)求,文中的示例代碼講解詳細(xì),感興趣的小伙伴可以跟隨小編一起學(xué)習(xí)一下

1. 簡單使用

RestTemplate底層是通過HttpURLConnection實(shí)現(xiàn)的。

（1）getForObject

RestTemplate restTemplate = new RestTemplate(https://blog.csdn.net/mryang125/article/details/80955558);
String url = "http://localhost:8080/user/{id}";
UserVo userVo = restTemplate.getForObject(url, UserVo.class, id);

第一個(gè)參數(shù)表示URL，第二個(gè)參數(shù)表示返回類型，第三個(gè)參數(shù)表示URI中對(duì)應(yīng)的參數(shù)，是一個(gè)可變長參數(shù)，可按順序?qū)懚鄠€(gè)參數(shù)。

（2）getForEntity

RestTemplate restTemplate = new RestTemplate();
String url = "http://localhost:8080/users/{userName}/{note}/{start}/{limit}";
//使用map封裝多個(gè)參數(shù)
Map<String, Object> params = new HashMap<>();
params.put("userName", userName);
params.put("note", note);
params.put("start", start);
params.put("limit", limit);
ResponseEntity<List> responseEntity = restTemplate.getForEntity(url, List.class, params);
List<UserVo> userVos = responseEntity.getBody();

（3）postForObject

RestTemplate restTemplate = new RestTemplate();
String url = "http://localhost:8080/user";
//設(shè)置請(qǐng)求頭
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
//創(chuàng)建請(qǐng)求實(shí)體對(duì)象
HttpEntity<UserVo> request = new HttpEntity<>(newUserVo, headers);
User user = restTemplate.postForObject(url, request, User.class);

（4）postForEntity

RestTemplate restTemplate = new RestTemplate();
String url = "http://localhost:8080/user";
//設(shè)置請(qǐng)求頭
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
//創(chuàng)建請(qǐng)求實(shí)體對(duì)象
HttpEntity<UserVo> request = new HttpEntity<>(newUserVo, headers);
//請(qǐng)求服務(wù)器
ResponseEntity<User> responseEntity = restTemplate.postForEntity(url, request, User.class);
//獲取響應(yīng)體
User user = responseEntity.getBody();
//獲取響應(yīng)頭
HttpHeaders respHeaders = responseEntity.getHeaders();
//獲取響應(yīng)屬性
List<String> success = respHeaders.get("success");
//獲取響應(yīng)狀態(tài)碼
int statusCode = responseEntity.getStatusCodeValue();

（5）delete

RestTemplate restTemplate = new RestTemplate();
restTemplate.delete("http://localhost:8080/use/{id}", id);

（6）exchange

RestTemplate還提供了一個(gè)exchange方法，該方法比上面的方法靈活，可以通過制定參數(shù)實(shí)現(xiàn)各種Http請(qǐng)求。下面列出Spring提供的八種方法。

<T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity, Class<T> responseType, Object... uriVariables) throws RestClientException;

<T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity, Class<T> responseType, Map<String, ?> uriVariables) throws RestClientException;

<T> ResponseEntity<T> exchange(URI url, HttpMethod method, HttpEntity<?> requestEntity, Class<T> responseType) throws RestClientException;

<T> ResponseEntity<T> exchange(String url,HttpMethod method, HttpEntity<?> requestEntity, ParameterizedTypeReference<T> responseType, Object... uriVariables) throws RestClientException;

<T> ResponseEntity<T> exchange(String url, HttpMethod method, HttpEntity<?> requestEntity, ParameterizedTypeReference<T> responseType, Map<String, ?> uriVariables) throws RestClientException;

<T> ResponseEntity<T> exchange(URI url, HttpMethod method, HttpEntity<?> requestEntity, ParameterizedTypeReference<T> responseType) throws RestClientException;

<T> ResponseEntity<T> exchange(RequestEntity<?> requestEntity, Class<T> responseType) throws RestClientException;

<T> ResponseEntity<T> exchange(RequestEntity<?> requestEntity, ParameterizedTypeReference<T> responseType) throws RestClientException;

下面寫一個(gè)使用例子：

RestTemplate restTemplate = new RestTemplate();
String url = "http://localhost:8080/user";
//設(shè)置請(qǐng)求頭
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
//創(chuàng)建請(qǐng)求實(shí)體對(duì)象
HttpEntity<UserVo> request = new HttpEntity<>(newUserVo, headers);
//請(qǐng)求服務(wù)器
ResponseEntity<User> responseEntity = restTemplate.exchange(url,  HttpMethod.POST, request, User.class);
//獲取響應(yīng)體
User user = responseEntity.getBody();
//獲取響應(yīng)頭
HttpHeaders respHeaders = responseEntity.getHeaders();
//獲取響應(yīng)屬性
List<String> success = respHeaders.get("success");
//獲取響應(yīng)狀態(tài)碼
int statusCode = responseEntity.getStatusCodeValue();

//獲取資源
String url1 = "http://localhost:8080/user/{id}";
ResponseEntity<User> responseEntity1 = restTemplate.exchange(url1,  HttpMethod.GET, null, User.class, id);
//獲取響應(yīng)體
User user1 = responseEntity1.getBody();

2. 使用泛型

使用泛型接收響應(yīng)，這里添加一個(gè)返回類型中泛型的使用方法：

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

//創(chuàng)建請(qǐng)求實(shí)體對(duì)象，這里將參數(shù)轉(zhuǎn)換為JSON字符串了
HttpEntity<String> request = new HttpEntity<>(paramJsonStr, headers);
//請(qǐng)求服務(wù)器
RestTemplate restTemplate = new RestTemplate();
String url = "http://www.baidu.com/task";
ResponseEntity<String> responseEntity = null;
try {
	//統(tǒng)一使用String接收響應(yīng)，再用Jackson轉(zhuǎn)為對(duì)應(yīng)的實(shí)體類
    responseEntity = restTemplate.postForEntity(url, request, String.class);
//這里使用try...catch是因?yàn)橛锌赡芤驗(yàn)榫W(wǎng)絡(luò)原因出現(xiàn)錯(cuò)誤，RestClientException 的子類 ResourceAccessException 異常
} catch (RestClientException e) {
    e.printStackTrace();
}

if (responseEntity != null) {
    //獲取響應(yīng)體
    String body = responseEntity.getBody();
    //使用Jackson轉(zhuǎn)為對(duì)應(yīng)的實(shí)體類，這里的Result中使用到了泛型，用來應(yīng)對(duì)多種格式
    ObjectMapper mapper = new ObjectMapper();
    Result<Ret> result = mapper.readValue(body, new TypeReference<Result<Ret>>() {});
    if (result != null) {
    	//使用了泛型，不同的請(qǐng)求這里就可以獲取到不同類型的data
        Ret data = result.getData();
        System.out.println("data : " + data);
    }
}

@Data
public class Result<T> {
    private String logid;
    private T data;
    private Integer status;
    private String message;
    private Double st;
    private Double crt;
}

@Data
public class Ret {
    private Boolean ret;
    private String photoId;
}

以上就是SpringBoot使用RestTemplate實(shí)現(xiàn)HTTP請(qǐng)求詳解的詳細(xì)內(nèi)容，更多關(guān)于SpringBoot RestTemplate實(shí)現(xiàn)HTTP請(qǐng)求的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章！

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