實現的curl請求多種方式

舉個列子

使用java如何實現以下請求curl -X POST -H 'Content-Type: application/json' -H 'Accept: application/json' -d '{ 
   "grant_type": "client_credentials",  
   "client_id": "YXA6i-Ak8Ol4Eei2l11ZjV-EAg", 
   "client_secret": "YXA6VunqiNxoB7IwXHInk1cGiXOOJfc",
   "ttl": "1024000"
 }' 'http://a1.easemob.com/easemob-demo/testapp/token'

可以使用Java中的HttpURLConnection或者Apache HttpClient來實現此curl請求，以下是使用HttpURLConnection的範例程式碼：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class Example {
    public static void main(String[] args) throws IOException {
        URL url = new URL("http://a1.easemob.com/easemob-demo/testapp/token");
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setRequestMethod("POST");
        con.setRequestProperty("Content-Type", "application/json");
        con.setRequestProperty("Accept", "application/json");

        String jsonBody = "{\"grant_type\":\"client_credentials\",\"client_id\":\"YXA6i-Ak8Ol4Eei2l11ZjV-EAg\",\"client_secret\":\"YXA6VunqiNxoB7IwXHInk1cGiXOOJfc\",\"ttl\":\"1024000\"}";

        con.setDoOutput(true);
        OutputStream os = con.getOutputStream();
        os.write(jsonBody.getBytes());
        os.flush();
        os.close();

        int responseCode = con.getResponseCode();

        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuilder response = new StringBuilder();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }

        in.close();

        System.out.println(response.toString());
    }
}

除了使用HttpURLConnection或者Apache HttpClient，還可以使用一些第三方開發庫進行訪問。

例如，可以使用OkHttp，以下是使用OkHttp的範例程式碼：

import okhttp3.*;

import java.io.IOException;

public class Example {
    public static void main(String[] args) throws IOException {
        OkHttpClient client = new OkHttpClient().newBuilder().build();

        MediaType mediaType = MediaType.parse("application/json");
        RequestBody body = RequestBody.create(mediaType, "{\"grant_type\":\"client_credentials\",\"client_id\":\"YXA6i-Ak8Ol4Eei2l11ZjV-EAg\",\"client_secret\":\"YXA6VunqiNxoB7IwXHInk1cGiXOOJfc\",\"ttl\":\"1024000\"}");
        Request request = new Request.Builder()
                .url("http://a1.easemob.com/easemob-demo/testapp/token")
                .method("POST", body)
                .addHeader("Content-Type", "application/json")
                .addHeader("Accept", "application/json")
                .build();

        Response response = client.newCall(request).execute();
        System.out.println(response.body().string());
    }
}

此外，如果使用Spring Framework或Spring Boot ，可以使用Spring的RestTemplate或WebClient訪問API。處理HTTP請求更簡單易用。

以下是使用RestTemplate的範例程式碼：

import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;

public class Example {
    public static void main(String[] args) {
        RestTemplate restTemplate = new RestTemplate();

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        headers.set("Accept", "application/json");

        String jsonBody = "{\"grant_type\":\"client_credentials\",\"client_id\":\"YXA6i-Ak8Ol4Eei2l11ZjV-EAg\",\"client_secret\":\"YXA6VunqiNxoB7IwXHInk1cGiXOOJfc\",\"ttl\":\"1024000\"}";

        ResponseEntity<String> response = restTemplate.postForEntity("http://a1.easemob.com/easemob-demo/testapp/token", headers, jsonBody, String.class);

        System.out.println(response.getBody());
    }
}

或者使用hutool-all工具類中的HttpResponse訪問API。
使用的依賴是

<dependency>
	<groupId>cn.hutoolgroupId>
    <artifactId>hutool-allartifactId>
    <version>5.8.18version>
dependency>

final String targetUrl = ”http://a1.easemob.com/easemob-demo/testapp/token“;
final Map<String, Object> params = new HashMap<>();
params.put("grant_type", "client_credentials");
params.put("client_id", this.huaXinConfig.getClientId());
 params.put("client_secret", this.huaXinConfig.getClientSecret());

HttpResponse response = HttpRequest.post(targetUrl).body(JSONUtil.toJsonStr(params)).timeout(20000).execute();

if (!response.isOk()) {
      return null;
}

String jsonBody = response.body();