Summary of usage methods of HttpClient and tool class encapsulation

1. Introduce httpclient dependencies

First, you need to confirm whether the httppclient dependency has been introduced in the project. If it has not been introduced, you need to add the following code to introduce the httppclient dependency:

<dependency>
    <groupId></groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

2. Send a GET request

2.1 Send a GET request (no parameters)

import ;
import ;
import ;
import ;
import ;
import ;

import ;
import ;

public class HttpClientUtils {
    public static String doGet() throws IOException {
        try (CloseableHttpClient httpClient = ()) {
            HttpGet httpGet = new HttpGet("/getDataList");

            try (CloseableHttpResponse httpResponse = (httpGet)) {
                if (().getStatusCode() == HttpStatus.SC_OK) {
                    return ((), StandardCharsets.UTF_8);
                }

                return null;
            }
        }
    }
}

2.2 Send GET request (with parameters)

The first method is to splice the parameters directly on the url, as shown below:

HttpGet httpGet = new HttpGet("/getDataList?pageIndex=1&pageSize=20");

The second method is to use URIBuilder to add parameters as follows:

import ;
import ;
import ;
import ;
import ;
import ;
import ;

import ;
import ;
import ;

public class HttpClientUtils {
    public static String doGet() throws IOException, URISyntaxException {
        try (CloseableHttpClient httpClient = ()) {

            URIBuilder uriBuilder = new URIBuilder("/getDataList");
            ("pageIndex", "1");
            ("pageSize", "20");

            HttpGet httpGet = new HttpGet(());

            try (CloseableHttpResponse httpResponse = (httpGet)) {
                if (().getStatusCode() == HttpStatus.SC_OK) {
                    return ((), StandardCharsets.UTF_8);
                }

                return null;
            }
        }
    }
}

3. Send a POST request

3.1 Send POST request (no parameters)

import ;
import ;
import ;
import ;
import ;
import ;

import ;
import ;

public class HttpClientUtils {
    public static String doPost() throws IOException {
        try (CloseableHttpClient httpClient = ()) {

            HttpPost httpPost = new HttpPost("/updateData");

            try (CloseableHttpResponse httpResponse = (httpPost)) {
                if (().getStatusCode() == HttpStatus.SC_OK) {
                    return ((), StandardCharsets.UTF_8);
                }

                return null;
            }
        }
    }
}

3.2 Send POST request (with parameters and form form method)

import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;

 import ;
 import ;
 import ;
 import ;

 public class HttpClientUtils {
     public static String doPost() throws IOException {
         try (CloseableHttpClient httpClient = ()) {

             HttpPost httpPost = new HttpPost("/updateData");

             List<NameValuePair> params = new ArrayList<>();
             (new BasicNameValuePair("id", "1"));
             (new BasicNameValuePair("name", "new name"));

             UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, StandardCharsets.UTF_8);
             (formEntity);

             try (CloseableHttpResponse httpResponse = (httpPost)) {
                 if (().getStatusCode() == HttpStatus.SC_OK) {
                     return ((), StandardCharsets.UTF_8);
                 }

                 return null;
             }
         }
     }
 }

3.3 Send POST request (with parameters, json method)

import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;

 import ;
 import ;

 public class HttpClientUtils {
     public static String doPost() throws IOException {
         try (CloseableHttpClient httpClient = ()) {

             HttpPost httpPost = new HttpPost("/updateData");

             String jsonBody = "{\"id\":\"1\",\"name\":New Name}";
             StringEntity stringEntity = new StringEntity(jsonBody);
             ("application/json;charset=utf-8");
             (stringEntity);

             try (CloseableHttpResponse httpResponse = (httpPost)) {
                 if (().getStatusCode() == HttpStatus.SC_OK) {
                     return ((), StandardCharsets.UTF_8);
                 }

                 return null;
             }
         }
     }
 }

4. Send PUT request

4.1 Send PUT request (no parameters)

import ;
import ;
import ;
import ;
import ;
import ;

import ;
import ;

public class HttpClientUtils {
    public static String doPut() throws IOException {
        try (CloseableHttpClient httpClient = ()) {

            HttpPut httpPut = new HttpPut("/updateData");

            try (CloseableHttpResponse httpResponse = (httpPut)) {
                if (().getStatusCode() == HttpStatus.SC_OK) {
                    return ((), StandardCharsets.UTF_8);
                }

                return null;
            }
        }
    }
}

4.2 Send PUT request (with parameters and form form method)

import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;

 import ;
 import ;
 import ;
 import ;

 public class HttpClientUtils {
     public static String doPut() throws IOException {
         try (CloseableHttpClient httpClient = ()) {

             HttpPut httpPut = new HttpPut("/updateData");

             List<NameValuePair> params = new ArrayList<>();
             (new BasicNameValuePair("id", "1"));
             (new BasicNameValuePair("name", "new name"));

             UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, StandardCharsets.UTF_8);
             (formEntity);

             try (CloseableHttpResponse httpResponse = (httpPut)) {
                 if (().getStatusCode() == HttpStatus.SC_OK) {
                     return ((), StandardCharsets.UTF_8);
                 }

                 return null;
             }
         }
     }
 }

4.3 Send PUT request (with parameters, json method)

import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;

 import ;
 import ;

 public class HttpClientUtils {
     public static String doPut() throws IOException {
         try (CloseableHttpClient httpClient = ()) {

             HttpPut httpPut = new HttpPut("/updateData");

             String jsonBody = "{\"id\":\"1\",\"name\":New Name}";
             StringEntity stringEntity = new StringEntity(jsonBody);
             ("application/json;charset=utf-8");
             (stringEntity);

             try (CloseableHttpResponse httpResponse = (httpPut)) {
                 if (().getStatusCode() == HttpStatus.SC_OK) {
                     return ((), StandardCharsets.UTF_8);
                 }

                 return null;
             }
         }
     }
 }

5. Send a DELETE request

5.1 Send DELETE request (no parameters)

import ;
import ;
import ;
import ;
import ;
import ;

import ;
import ;

public class HttpClientUtils {
    public static String doDelete() throws IOException {
        try (CloseableHttpClient httpClient = ()) {

            HttpDelete httpDelete = new HttpDelete("/updateData");

            try (CloseableHttpResponse httpResponse = (httpDelete)) {
                if (().getStatusCode() == HttpStatus.SC_OK) {
                    return ((), StandardCharsets.UTF_8);
                }

                return null;
            }
        }
    }
}

6. Add a request header

Generally speaking, requesting third-party interfaces requires signatures, timestamps and other request headers. Taking POST request as an example, the code to add the request header is as follows:

("Content-Type", "application/json;charset=utf-8");
("signature", "3045022100875efcef9eb54626bb0168a6baa7c61265d0001d49243f");
("timestamp", (()));

The method of adding request headers to GET request, PUT request, and DELETE request is the same as above.

7. Timeout time setting

If you need to customize the connection timeout and data transmission timeout for HTTP requests, the code is as follows (taking the POST request as an example):

RequestConfig requestConfig = ()
                    .setConnectTimeout(5000)
                    .setSocketTimeout(10000)
                    .build();
(requestConfig);

The method of setting the timeout time of GET request, PUT request, and DELETE request is the same as above.

8. Tool class encapsulation

The complete tool class code is as follows:

import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;
 import ;

 import ;
 import ;
 import ;
 import ;
 import ;
 import ;

 public class HttpClientUtils {
     /**
      * Connection establishment timeout time (unit: milliseconds)
      */
     private static final int CONNECT_TIMEOUT = 5000;

     /**
      * Data transmission timeout time (unit: milliseconds)
      */
     private static final int SOCKET_TIMEOUT = 10000;

     /**
      * Perform GET request
      *
      * @param url Request address
      * @param headers Request header
      * @return Response content string
      */
     public static String doGet(String url, Map<String, String> headers) throws IOException {
         HttpGet httpGet = new HttpGet(url);

         // Set request header
         setHeaders(httpGet, headers);

         return executeRequest(httpGet);
     }

     /**
      * Perform GET request
      *
      * @param url Request address
      * @param headers Request header
      * @param params Request parameters
      * @return Response content string
      */
     public static String doGet(String url, Map<String, String> headers, Map<String, String> params) throws IOException, URISyntaxException {
         URIBuilder uriBuilder = new URIBuilder(url);

         // Set request parameters
         if (params != null && !()) {
             for (<String, String> entry : ()) {
                 ((), ());
             }
         }

         HttpGet httpGet = new HttpGet(());

         // Set request header
         setHeaders(httpGet, headers);

         return executeRequest(httpGet);
     }

     /**
      * Execute POST request (form method)
      *
      * @param url Request address
      * @return Response content string
      */
     public static String doPost(String url) throws IOException {
         return doPost(url, null, null);
     }

     /**
      * Execute POST request (form method)
      *
      * @param url Request address
      * @param headers Request header
      * @return Response content string
      */
     public static String doPost(String url, Map<String, String> headers) throws IOException {
         return doPost(url, headers, null);
     }

     /**
      * Execute POST request (form method)
      *
      * @param url Request address
      * @param headers Request header
      * @param params Request parameters
      * @return Response content string
      */
     public static String doPost(String url, Map<String, String> headers, Map<String, String> params) throws IOException {
         HttpPost httpPost = new HttpPost(url);

         // Set request header
         setHeaders(httpPost, headers);

         // Build form parameters
         if (params != null) {
             List<NameValuePair> paramList = new ArrayList<>();
             for (<String, String> entry : ()) {
                 (new BasicNameValuePair((), ()));
             }
             (new UrlEncodedFormEntity(paramList, StandardCharsets.UTF_8));
         }

         return executeRequest(httpPost);
     }

     /**
      * Execute POST request (JSON format)
      *
      * @param url Request address
      * @param headers Request header
      * @return Response content string
      */
     public static String doPostJson(String url, Map<String, String> headers) throws IOException {
         return doPostJson(url, headers, null);
     }

     /**
      * Execute POST request (JSON format)
      *
      * @param url Request address
      * @param headers Request header
      * @param jsonBody JSON request body string
      * @return Response content string
      */
     public static String doPostJson(String url, Map<String, String> headers, String jsonBody) throws IOException {
         HttpPost httpPost = new HttpPost(url);

         // Add JSON request header
         addJsonHeader(httpPost, headers);
         // Add custom request header
         setHeaders(httpPost, headers);

         // Set up JSON request body
         if (jsonBody != null) {
             StringEntity entity = new StringEntity(jsonBody,
                     ContentType.APPLICATION_JSON.withCharset(StandardCharsets.UTF_8));
             (entity);
         }

         return executeRequest(httpPost);
     }

     /**
      * Execute PUT request (JSON format)
      *
      * @param url Request address
      * @param headers Request header
      * @param jsonBody JSON request body string
      * @return Response content string
      */
     public static String doPut(String url, Map<String, String> headers, String jsonBody) throws IOException {
         HttpPut httpPut = new HttpPut(url);

         // Add JSON request header
         addJsonHeader(httpPut, headers);
         // Add custom request header
         setHeaders(httpPut, headers);

         // Set up JSON request body
         if (jsonBody != null) {
             StringEntity entity = new StringEntity(jsonBody,
                     ContentType.APPLICATION_JSON.withCharset(StandardCharsets.UTF_8));
             (entity);
         }

         return executeRequest(httpPut);
     }

     /**
      * Perform DELETE request
      *
      * @param url Request address
      * @param headers Request header
      * @return Response content string
      */
     public static String doDelete(String url, Map<String, String> headers) throws IOException {
         HttpDelete httpDelete = new HttpDelete(url);

         // Set request header
         setHeaders(httpDelete, headers);

         return executeRequest(httpDelete);
     }

     /**
      * Create an HttpClient with timeout configuration
      *
      * @return HttpClient instance
      */
     private static CloseableHttpClient createHttpClient() {
         RequestConfig requestConfig = ()
                 .setConnectTimeout(CONNECT_TIMEOUT)
                 .setSocketTimeout(SOCKET_TIMEOUT)
                 .build();

         Return ()
                 .setDefaultRequestConfig(requestConfig)
                 .build();
     }

     /**
      * Add JSON request header
      *
      * @param httpRequest HTTP request object
      * @param headers Request header
      */
     private static void addJsonHeader(HttpRequestBase httpRequest, Map<String, String> headers) {
         if (headers == null || !("Content-Type")) {
             ("Content-Type", "application/json;charset=utf-8");
         }
     }

     /**
      * Set request header
      *
      * @param httpRequest HTTP request object
      * @param headers Request header
      */
     private static void setHeaders(HttpRequestBase httpRequest, Map<String, String> headers) {
         if (headers == null || ()) {
             return;
         }

         for (<String, String> entry : ()) {
             ((), ());
         }
     }

     /**
      * Unified execution of requests and processing responses
      *
      * @param httpRequest HTTP request object
      * @return Response content string
      */
     private static String executeRequest(HttpRequestBase httpRequest) throws IOException {
         try (CloseableHttpClient httpClient = createHttpClient()) {
             try (CloseableHttpResponse response = (httpRequest)) {
                 return handleResponse(response);
             }
         }
     }

     /**
      * Processing response results
      *
      * @param response HTTP response object
      * @return Response content string
      */
     private static String handleResponse(CloseableHttpResponse response) throws IOException {
         int statusCode = ().getStatusCode();
         if (statusCode != HttpStatus.SC_OK) {
             throw new RuntimeException("HTTP request failed, status code: " + statusCode);
         }

         HttpEntity entity = ();
         if (entity != null) {
             return (entity, StandardCharsets.UTF_8);
         }
         return null;
     }
 }