httpclient 发送请求

喜欢ヅ旅行 2023-10-07 22:48 80阅读 0赞

HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

## 一、使用的Jar包 ##

首先需要在maven中引入如下包

<dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.13</version>
    </dependency>
    
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>2.0.18</version>
    </dependency>

## 二、接口代码 ##

1.  #### Get的无参/有参请求 ####

/**
     * @param url     接口地址
     * @param headers 请求头
     * @Description get请求
     */
    public static String getData(String url, Map<String, String> headers) {
        String StringResult = "";
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet(url);
        if (headers != null && !headers.isEmpty()) {
            for (String head : headers.keySet()) {
                httpGet.addHeader(head, headers.get(head));
            }
        }
        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpGet);
            HttpEntity entity = response.getEntity();
            StringResult = EntityUtils.toString(entity, StandardCharsets.UTF_8).trim();
            EntityUtils.consume(entity);
        } catch (Exception e) {
            e.printStackTrace();
            StringResult = "errorException:" + e.getMessage();
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return StringResult;
    }

请求实列：在这里无参请求就不展示，可自行试验

Map<String, String> headers = new HashMap<>();
    headers.put("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36");
    String data = getData("https://api.vvhan.com/api/covid?city=重庆", headers);
    System.out.println(data);

请求结果：

{
      "success": true,
      "data": {
        "updatetime": "2022-12-23 09:46:10",
        "country": "中国",
        "province": "重庆",
        "city": "重庆",
        "now": {
          "sure_new_loc": "未公布",
          "sure_new_hid": "未公布",
          "sure_present": 3108
        },
        "history": {
          "sure_cnt": 10452,
          "cure_cnt": 7337,
          "die_cnt": 7
        },
        "danger": {
          "high_risk": 0,
          "medium_risk": 0
        }
      }
    }

1.  #### Post请求（application/x-www-form-urlencoded） ####

/**
     * @param url     接口地址
     * @param list    NameValuePair（简单名称值对节点类型）类似html中的input
     * @param headers 请求头（默认Content-Type：application/x-www-form-urlencoded; charset=UTF-8）
     * @Description post请求
     */
    public static String postData(String url, ArrayList<NameValuePair> list, Map<String, String> headers) {
        String StringResult = "";
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        if (list != null && !list.isEmpty()) {
            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(list, Consts.UTF_8);
            httpPost.setEntity(formEntity);
        }
        httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
        if (headers != null && !headers.isEmpty()) {
            for (String head : headers.keySet()) {
                httpPost.addHeader(head, headers.get(head));
            }
        }
        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpPost);
            HttpEntity entity = response.getEntity();
            StringResult = EntityUtils.toString(entity, StandardCharsets.UTF_8);
            EntityUtils.consume(entity);
        } catch (Exception e) {
            StringResult = "errorException:" + e.getMessage();
            e.printStackTrace();
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return StringResult;
    }

请求实列：

ArrayList<NameValuePair> list = new ArrayList<>();
    list.add(new BasicNameValuePair("username", "用户名"));
    list.add(new BasicNameValuePair("password", "1234"));
    String s = postData("http://127.0.0.1:3000/aaa/file/testPost.jsp", list, null);
    System.out.println(s);

请求结果：

用户名
    1234
    application/x-www-form-urlencoded; charset=UTF-8

1.  #### Post请求（*application/json*） ####

/**
     * @param url        接口地址
     * @param jsonString json字符串
     * @param headers    请求头(默认Content-Type：application/json; charset=UTF-8)
     * @Description post Json 请求
     */
    public static String postJsonData(String url, @NotNull String jsonString, Map<String, String> headers) {
        String StringResult = "";
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
    
        StringEntity jsonEntity = new StringEntity(jsonString, Consts.UTF_8);
        jsonEntity.setContentEncoding(Consts.UTF_8.name());
    
        httpPost.setEntity(jsonEntity);
        httpPost.addHeader("Content-Type", "application/json; charset=UTF-8");
        if (headers != null && !headers.isEmpty()) {
            for (String head : headers.keySet()) {
                httpPost.addHeader(head, headers.get(head));
            }
        }
        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpPost);
            HttpEntity entity = response.getEntity();
            StringResult = EntityUtils.toString(entity, StandardCharsets.UTF_8);
            EntityUtils.consume(entity);
        } catch (Exception e) {
            StringResult = "errorException:" + e.getMessage();
            e.printStackTrace();
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return StringResult;
    }

请求实列：

JSONObject jsonObject = new JSONObject();
    jsonObject.put("demo", "456789");
    jsonObject.put("demo1", "哈哈哈爱发火");
    String s = postJsonData("http://127.0.0.1:3000/api/workflow/v1/insert2", jsonObject.toJSONString(), null);
    System.out.println(s);

请求结果：

![bcb97fd0a8ecd54b41af3dc3ec193997.png][]

1.  #### Get请求url拼接 ####

/**
     * @param url    接口地址(无参数/有参)
     * @param params 拼接参数集合
     * @Description get请求URL拼接参数 & URL编码
     */
    public static String getAppendUrl(String url, Map<String, String> params) {
        StringBuffer buffer = new StringBuffer(url);
        if (params != null && !params.isEmpty()) {
            for (String key : params.keySet()) {
                if (buffer.indexOf("?") >= 0) {
                    buffer.append("&");
                } else {
                    buffer.append("?");
                }
                String value = "";
                try {
                    value = URLEncoder.encode(params.get(key), StandardCharsets.UTF_8.name());
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                buffer.append(key)
                        .append("=")
                        .append(value);
            }
        }
        return buffer.toString();
    }

请求实列：

Map<String, String> params = new HashMap<>();
    params.put("city", "重庆");
    params.put("number", "手机号");
    String appendUrl = getAppendUrl("https://TestGetSplice/index", params);
    String appendUrl1 = getAppendUrl("https://TestGetSplice/index?a=33", params);
    System.out.println(appendUrl);
    System.out.println(appendUrl1);

请求结果：

https://TestGetSplice/index?number=%E6%89%8B%E6%9C%BA%E5%8F%B7&city=%E9%87%8D%E5%BA%86
    https://TestGetSplice/index?a=33&number=%E6%89%8B%E6%9C%BA%E5%8F%B7&city=%E9%87%8D%E5%BA%86

### 三、使用的类 ###

import com.alibaba.fastjson.JSONObject;
    import com.sun.istack.internal.NotNull;
    import org.apache.http.Consts;
    import org.apache.http.HttpEntity;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.entity.StringEntity;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    import java.net.URLEncoder;
    import java.nio.charset.StandardCharsets;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.Map;

### 四、标准字符集的常量定义 ###

这些字符集保证在Java平台的每个实现上都可用。

import java.nio.charset.StandardCharsets;
    StandardCharsets.UTF_8

### 五、请求状态常量 ###

import org.apache.http.HttpStatus;
    // 200
    HttpStatus.SC_OK

[bcb97fd0a8ecd54b41af3dc3ec193997.png]: https://img-blog.csdnimg.cn/img_convert/bcb97fd0a8ecd54b41af3dc3ec193997.png