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Spring RestTemplate使用方法總結(jié)

2025-04-11 10:40 申城異鄉(xiāng)人閱讀(82) 評(píng)論(0) 收藏舉報(bào)

Spring RestTemplate使用方法總結(jié)。

1. 引入依賴

首先，需要確認(rèn)項(xiàng)目中是否直接或者間接引入過(guò)spring-web依賴，如果沒(méi)有引入過(guò)，需要在pom.xml中添加以下代碼引入依賴：

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>4.3.24.RELEASE</version>
</dependency>

2. 發(fā)送GET請(qǐng)求

使用RestTemplate發(fā)送GET請(qǐng)求主要有getForObject()和getForEntity()2個(gè)方法，每個(gè)方法分別提供了3種不同的重載。

2.1 使用getForObject發(fā)送GET請(qǐng)求(無(wú)參數(shù))

使用getForObject()實(shí)現(xiàn)：

RestTemplate restTemplate = new RestTemplate();

String url = "https://www.example.com/getCurrentEnv";
String response = restTemplate.getForObject(url, String.class);
System.out.println(response);

假設(shè)以上接口返回的報(bào)文為：

{
    "serverAddress": "www.example.dev.com",
    "env": "dev"
}

也可以直接解析為自定義的類型：

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class EnvInfo {
    private String serverAddress;

    private String env;
}

RestTemplate restTemplate = new RestTemplate();

String url = "https://www.example.com/getCurrentEnv";
EnvInfo response = restTemplate.getForObject(url, EnvInfo.class);
System.out.println(JSON.toJSONString(response));

2.2 使用getForEntity發(fā)送GET請(qǐng)求(無(wú)參數(shù))

也可以使用getForEntity()實(shí)現(xiàn)和2.1同樣的功能，代碼如下所示：

RestTemplate restTemplate = new RestTemplate();

String url = "https://www.example.com/getCurrentEnv";
ResponseEntity<EnvInfo> responseEntity = restTemplate.getForEntity(url, EnvInfo.class);
if (responseEntity.getStatusCode() == HttpStatus.OK) {
    EnvInfo response = responseEntity.getBody();
    System.out.println(JSON.toJSONString(response));
}

2.3 使用getForObject發(fā)送GET請(qǐng)求(帶參數(shù))

第一種方法是直接在url上拼接上參數(shù)，如下所示：

RestTemplate restTemplate = new RestTemplate();

String url = "https://www.example.com/getDataList?pageIndex=1&pageSize=20";
EnvInfo response = restTemplate.getForObject(url, EnvInfo.class);
System.out.println(JSON.toJSONString(response));

第二種方法是使用占位符添加參數(shù)，如下所示：

RestTemplate restTemplate = new RestTemplate();

String url = "https://www.example.com/getDataList?pageIndex={1}&pageSize={2}";
EnvInfo response = restTemplate.getForObject(url, EnvInfo.class, 1, 20);
System.out.println(JSON.toJSONString(response));

以上代碼也可以替換為：

RestTemplate restTemplate = new RestTemplate();

String url = "https://www.example.com/getDataList?pageIndex={pageIndex}&pageSize={pageSize}";
Map<String, String> uriVariables = new HashMap<>();
uriVariables.put("pageIndex", "1");
uriVariables.put("pageSize", "20");
EnvInfo response = restTemplate.getForObject(url, EnvInfo.class, uriVariables);
System.out.println(JSON.toJSONString(response));

注意事項(xiàng)：

uriVariables中的key必須和url中的占位符名稱一致，否則會(huì)拋出異常：

java.lang.IllegalArgumentException: Map has no value for 'pageIndex'

第三種方法是使用UriComponentsBuilder添加參數(shù)，該種方法相比于前兩種方法更加靈活，可以實(shí)現(xiàn)動(dòng)態(tài)添加參數(shù)，代碼如下所示：

RestTemplate restTemplate = new RestTemplate();

String httpUrl = "https://www.example.com/getDataList";
UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromHttpUrl(httpUrl);
uriComponentsBuilder.queryParam("pageIndex", 1);
uriComponentsBuilder.queryParam("pageSize", 20);

String url = uriComponentsBuilder.toUriString();
EnvInfo response = restTemplate.getForObject(url, EnvInfo.class);
System.out.println(JSON.toJSONString(response));

2.4 使用getForEntity發(fā)送GET請(qǐng)求(帶參數(shù))

也可以使用getForEntity()實(shí)現(xiàn)和2.3同樣的功能，代碼如下所示：

RestTemplate restTemplate = new RestTemplate();

String httpUrl = "https://www.example.com/getDataList";
UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromHttpUrl(httpUrl);
uriComponentsBuilder.queryParam("pageIndex", 1);
uriComponentsBuilder.queryParam("pageSize", 20);

String url = uriComponentsBuilder.toUriString();
ResponseEntity<EnvInfo> responseEntity = restTemplate.getForEntity(url, EnvInfo.class);
if (responseEntity.getStatusCode() == HttpStatus.OK) {
    EnvInfo response = responseEntity.getBody();
    System.out.println(JSON.toJSONString(response));
}

2.5 getForObject與getForEntity的區(qū)別

getForEntity()與getForObject()相比，返回值用了ResponseEntity進(jìn)行封裝，可以多獲取到以下2種信息：

HTTP狀態(tài)碼
Response Headers

代碼示例：

RestTemplate restTemplate = new RestTemplate();

String httpUrl = "https://www.example.com/getDataList";
UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromHttpUrl(httpUrl);
uriComponentsBuilder.queryParam("pageIndex", 1);
uriComponentsBuilder.queryParam("pageSize", 20);

String url = uriComponentsBuilder.toUriString();
ResponseEntity<EnvInfo> responseEntity = restTemplate.getForEntity(url, EnvInfo.class);
System.out.println("statusCode: " + responseEntity.getStatusCode().toString());
System.out.println("statusCodeValue: " + responseEntity.getStatusCodeValue());
responseEntity.getHeaders().forEach((key, values) -> {
    System.out.println(key + ": " + values);
});

輸出結(jié)果：

statusCode: 200
statusCodeValue: 200
Server: [openresty]
Date: [Thu, 10 Apr 2025 05:39:02 GMT]
Content-Type: [application/json]
Transfer-Encoding: [chunked]
Connection: [keep-alive]

其中Response Headers輸出部分和Chrome瀏覽器Network中的Response Headers是一致的：

2.6 發(fā)送GET請(qǐng)求(帶參數(shù)及請(qǐng)求頭)

一般情況下，請(qǐng)求第三方接口都需要簽名、時(shí)間戳等請(qǐng)求頭，但getForObject()和getForEntity()都不支持，

此時(shí)需要使用exchange()方法，代碼如下所示：

RestTemplate restTemplate = new RestTemplate();

String httpUrl = "https://www.example.com/getDataList";
UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromHttpUrl(httpUrl);
uriComponentsBuilder.queryParam("pageIndex", 1);
uriComponentsBuilder.queryParam("pageSize", 20);

HttpHeaders headers = new HttpHeaders();
headers.set("signature", "3045022100875efcef9eb54626bb0168a6baa7c61265d0001d49243f");
headers.set("timestamp", String.valueOf(System.currentTimeMillis()));

String url = uriComponentsBuilder.toUriString();
ResponseEntity<EnvInfo> responseEntity = restTemplate.exchange(url,
        HttpMethod.GET,
        new HttpEntity<>(headers),
        EnvInfo.class);
if (responseEntity.getStatusCode() == HttpStatus.OK) {
    EnvInfo response = responseEntity.getBody();
    System.out.println(JSON.toJSONString(response));
}

3. 發(fā)送POST請(qǐng)求

使用RestTemplate發(fā)送POST請(qǐng)求主要有postForObject()和postForEntity()2個(gè)方法，每個(gè)方法分別提供了3種不同的重載。

3.1 發(fā)送POST請(qǐng)求(帶參數(shù)、json方式)

使用postForObject()實(shí)現(xiàn)：

RestTemplate restTemplate = new RestTemplate();

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);

LoginParams loginParams = new LoginParams();
loginParams.setUsername("zhangsan");
loginParams.setPassword("123456");

HttpEntity<LoginParams> request = new HttpEntity<>(loginParams, headers);

String url = "https://www.example.com/login";
String response = restTemplate.postForObject(url, request, String.class);
System.out.println(response);

LoginParams的定義如下所示：

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class LoginParams {
    private String username;

    private String password;
}

假設(shè)以上接口返回的報(bào)文為：

{
    "code": 200,
    "expire": "2025-04-11 14:42:22",
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE3NDQzNTM3NDIsImlkZW50aXR5"
}

也可以直接解析為自定義的類型：

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class LoginResponse {
    private Integer code;

    private String expire;

    private String token;
}

RestTemplate restTemplate = new RestTemplate();

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);

LoginParams loginParams = new LoginParams();
loginParams.setUsername("zhangsan");
loginParams.setPassword("123456");

HttpEntity<LoginParams> request = new HttpEntity<>(loginParams, headers);

String url = "https://www.example.com/login";
LoginResponse response = restTemplate.postForObject(url, request, LoginResponse.class);
System.out.println(JSON.toJSONString(response));

也可以使用postForEntity()實(shí)現(xiàn)同樣的功能，代碼如下所示：

ResponseEntity<LoginResponse> responseEntity = restTemplate.postForEntity(url, request, LoginResponse.class);
if (responseEntity.getStatusCode() == HttpStatus.OK) {
    LoginResponse response = responseEntity.getBody();
    System.out.println(JSON.toJSONString(response));
}

3.2 發(fā)送POST請(qǐng)求(帶參數(shù)、form表單方式)

使用postForObject()實(shí)現(xiàn)：

RestTemplate restTemplate = new RestTemplate();

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
map.add("username", "zhangsan");
map.add("password", "123456");

HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(map, headers);

String url = "https://www.example.com/login";
LoginResponse response = restTemplate.postForObject(url, request, LoginResponse.class);
System.out.println(JSON.toJSONString(response));

也可以使用postForEntity()實(shí)現(xiàn)同樣的功能，代碼如下所示：

ResponseEntity<LoginResponse> responseEntity = restTemplate.postForEntity(url, request, LoginResponse.class);
if (responseEntity.getStatusCode() == HttpStatus.OK) {
    LoginResponse response = responseEntity.getBody();
    System.out.println(JSON.toJSONString(response));
}

3.3 postForObject與postForEntity的區(qū)別

postForObject()與postForEntity()的區(qū)別，與getForEntity()與getForObject()的區(qū)別一樣，

返回值用了ResponseEntity進(jìn)行封裝。

4. 超時(shí)時(shí)間設(shè)置

如果需要自定義HTTP請(qǐng)求的連接超時(shí)時(shí)間和數(shù)據(jù)傳輸超時(shí)時(shí)間，代碼如下所示：

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

@Configuration
public class RestTemplateConfig {
    @Value("${restTemplate.connectTimeout:5000}")
    private int connectTimeout;

    @Value("${restTemplate.readTimeout:10000}")
    private int readTimeout;

    @Bean
    public RestTemplate restTemplate() {
        SimpleClientHttpRequestFactory simpleClientHttpRequestFactory = new SimpleClientHttpRequestFactory();
        simpleClientHttpRequestFactory.setConnectTimeout(connectTimeout);
        simpleClientHttpRequestFactory.setReadTimeout(readTimeout);

        return new RestTemplate(simpleClientHttpRequestFactory);
    }
}

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