JavaHttpRequest使用详解

一、JavaHttpRequest简介

JavaHttpRequest是一款基于Java语言开发的http请求工具，可以用于实现Java程序对HTTP接口进行调用。它支持多种请求方法、参数设置、数据传输等，使用简单方便，而且还提供了丰富的回调函数，方便用户对响应数据进行处理。

二、JavaHttpRequest的使用

1、引入JavaHttpRequest库

在使用JavaHttpRequest之前，需要先引入相关的库文件。我们通过maven来引入：

    


   
    
    org.apache.httpcomponents
    
    
    httpclient
    
    
    4.5.13
    

   


   
    
    org.apache.httpcomponents
    
    
    httpmime
    
    
    4.5.13
    

   


   
    
    org.apache.httpcomponents
    
    
    httpcore
    
    
    4.4.13
    

    


   
    
    com.alibaba
    
    
    fastjson
    
    
    1.2.62
    

   


   
    
    org.projectlombok
    
    
    lombok
    
    
    1.18.22
    
    
    provided
    

   


   
    
    org.slf4j
    
    
    slf4j-api
    
    
    1.7.32
    

   

2、JavaHttpRequest请求示例

下面我们给出JavaHttpRequest的具体使用示例：

    
import com.alibaba.fastjson.JSONObject;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpEntity;
import org.apache.http.HttpHeaders;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

@Slf4j
public class HttpRequest {

    public static final String METHOD_GET = "GET";
    public static final String METHOD_POST = "POST";
    public static final String METHOD_PUT = "PUT";
    public static final String METHOD_DELETE = "DELETE";

    /**
     * 发送HTTP请求
     *
     * @param url
     * @param method
     * @param headers
     * @param params
     * @return
     */
    @SneakyThrows
    public static HttpResponseEntity doHttpRequest(String url, String method, JSONObject headers, JSONObject params) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpResponse httpResponse;

        if (METHOD_GET.equals(method)) { // GET
            String queryString = RequestParamsUtil.getQueryString(params);
            HttpGet httpGet = new HttpGet(url + "?" + queryString);
            for (String key : headers.keySet()) {
                httpGet.setHeader(key, headers.getString(key));
            }
            httpResponse = httpClient.execute(httpGet);

        } else if (METHOD_POST.equals(method)) { // POST
            HttpPost httpPost = new HttpPost(url);
            for (String key : headers.keySet()) {
                httpPost.setHeader(key, headers.getString(key));
            }
            StringEntity entity = new StringEntity(params.toJSONString(), ContentType.APPLICATION_JSON);
            httpPost.setEntity(entity);
            httpResponse = httpClient.execute(httpPost);

        } else if (METHOD_PUT.equals(method)) { // PUT
            HttpPut httpPut = new HttpPut(url);
            for (String key : headers.keySet()) {
                httpPut.setHeader(key, headers.getString(key));
            }
            StringEntity entity = new StringEntity(params.toJSONString(), ContentType.APPLICATION_JSON);
            httpPut.setEntity(entity);
            httpResponse = httpClient.execute(httpPut);

        } else if (METHOD_DELETE.equals(method)) { // DELETE
            HttpDelete httpDelete = new HttpDelete(url);
            for (String key : headers.keySet()) {
                httpDelete.setHeader(key, headers.getString(key));
            }
            httpResponse = httpClient.execute(httpDelete);

        } else {
            throw new RuntimeException("http method not support");
        }

        HttpResponseEntity res = new HttpResponseEntity();
        res.setStatusCode(httpResponse.getStatusLine().getStatusCode());
        HttpEntity httpEntity = httpResponse.getEntity();

        if (httpEntity != null) {
            res.setContent(EntityUtils.toString(httpEntity, "UTF-8"));
        }
        return res;
    }

    /**
     * 发送HTTP请求
     *
     * @param url
     * @param method
     * @param headers
     * @param payload
     * @return
     * @throws IOException
     */
    public static String doHttpRequest(String url, String method, JSONObject headers, String payload) throws IOException {

        HttpEntityEnclosingRequestBase requestBase = null;
        if (method.equalsIgnoreCase("post")) {
            requestBase = new HttpPost(url);
        } else if (method.equalsIgnoreCase("put")) {
            requestBase = new HttpPut(url);
        } else if (method.equalsIgnoreCase("delete")) {
            requestBase = new HttpDeleteWithBody(url);
        }

        for (String key : headers.keySet()) {
            requestBase.setHeader(key, headers.getString(key));
        }

        if (payload != null && !payload.isEmpty()) {
            requestBase.setEntity(new StringEntity(payload, ContentType.APPLICATION_JSON));
        }

        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpResponse response = httpclient.execute(requestBase);

        String result = null;
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            result = EntityUtils.toString(entity, "UTF-8");
        }
        EntityUtils.consume(entity);
        httpclient.close();

        return result;
    }

}
    

三、JavaHttpRequest的参数设置

1、HTTP请求头设置

使用JavaHttpRequest进行请求时，可能需要设置HTTP请求头，可以通过以下方法来实现：

    
JSONObject headers = new JSONObject();
headers.put("Content-Type", "application/json");
headers.put("Authorization", "Bearer " + token);
HttpResponseEntity responseEntity = HttpRequest.doHttpRequest(url, "POST", headers, requestBody);
log.info(responseEntity.getContent());
    

2、HTTP请求参数设置

除了设置HTTP请求头之外，我们还需要设置HTTP请求参数，在JavaHttpRequest中，我们可以使用JSONObject对象来设置请求参数，具体示例如下：

    
JSONObject params = new JSONObject();
params.put("username", "admin");
params.put("password", "123456");
HttpResponseEntity responseEntity = HttpRequest.doHttpRequest(url, "POST", null, params);
log.info(responseEntity.getContent());
    

四、JavaHttpRequest的响应处理

1、获取HTTP响应码

在JavaHttpRequest中，我们可以通过HttpResponseEntity对象来获取HTTP响应码，具体示例如下：

    
HttpResponseEntity responseEntity = HttpRequest.doHttpRequest(url, "GET", null, null);
int statusCode = responseEntity.getStatusCode();
log.info("statusCode: {}", statusCode);
    

2、获取HTTP响应头

除了获取HTTP响应码之外，我们还可以获取HTTP响应头信息，具体示例如下：

    
HttpResponseEntity responseEntity = HttpRequest.doHttpRequest(url, "GET", null, null);
Map
    headers = responseEntity.getHeaders();
for (String key : headers.keySet()){
    log.info(key + ": " + headers.get(key));
}
    
   

3、获取HTTP响应内容

最重要的是获取HTTP响应内容，JavaHttpRequest提供了很多种获取响应内容的方法，包括获取字符串、文件、流等，具体示例如下：

    
HttpResponseEntity responseEntity = HttpRequest.doHttpRequest(url, "POST", headers, requestBody);
String content = responseEntity.getContent(); // 获取响应字符串
log.info("response content: {}", content);
    

此外，JavaHttpRequest还提供了其他的处理方法，如获取响应流、获取响应文件等，具体请参见官方文档。

五、JavaHttpRequest的异常处理

在JavaHttpRequest中，如果请求失败或出现异常，会抛出异常，我们需要对异常进行捕获和处理，具体示例如下：

    
try {
    HttpResponseEntity responseEntity = HttpRequest.doHttpRequest(url, "GET", null, null);
    int statusCode = responseEntity.getStatusCode();
    log.info("statusCode: {}", statusCode);
} catch (Exception e) {
    log.error("http request error", e);
}
    

六、小结

JavaHttpRequest是一款优秀的http请求工具，支持多种请求方法、参数设置、数据传输等，并提供了丰富的回调函数，方便用户对响应数据进行处理。本文从JavaHttpRequest的介绍、使用、参数设置、响应处理以及异常处理等多个方面进行详细介绍，希望能够对广大Java开发者有所帮助。