Java使用HttpClient发送GET和POST（带参数）请求

2024-01-18 19:46| 来源: 网络整理| 查看: 265

发送GET和POST请求

最近和朋友在开展一个新的项目，需要用到JAVA后台，所以这两天我在努力的进行知识迁移和学习，毕竟对JAVA语言不是很熟悉，所以有许多东西需要学习的。今天我需要调用某平台的接口，需要用到常用的GET和POST请求。

看了需对代码示例，我的天哪，JAVA对待我这个新人，还真不友好，写个请求还需要弄一大堆代码，（据了解其实是有很好用的封装类库，我还不会用）。相比之下，Python的Requets还是更好上手一点~好了，废话不多说，下面呢，我们开始自己封装一下，HttpUtil工具类,有了它妈妈再也不用担心我的JAVA了！额…好吧，过来人告诉我，孩子，你想多了！

第一步，引入依赖 org.apache.httpcomponents httpclient 4.5.2 org.apache.httpcomponents httpcore 4.4.5 第二步，好吧，最后一步，封装工具类 package com.example.demo.utils; import java.io.IOException; import java.util.Map; import com.google.gson.JsonObject; import org.apache.http.*; import org.apache.http.clienthods.CloseableHttpResponse; import org.apache.http.clienthods.HttpGet; import org.apache.http.clienthods.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.util.EntityUtils; # 基本类结构 /** * @author Joe_yoy * */ public class HttpUtil { private static final CloseableHttpClient httpclient = HttpClients.createDefault(); // 继续 }

这里是我用到的工具类， PS:关于json处理的包，我使用了gson 具体使用可以查看某网友的gson的简明使用

2.1 GET请求，不带参数

/** * 发送HttpGet请求 * @param url * @return */ public static String sendGet(String url) { HttpGet httpget = new HttpGet(url); CloseableHttpResponse response = null; try { response = httpclient.execute(httpget); } catch (IOException e1) { e1.printStackTrace(); } String result = null; try { HttpEntity entity = response.getEntity(); if (entity != null) { result = EntityUtils.toString(entity); } } catch (ParseException | IOException e) { e.printStackTrace(); } finally { try { response.close(); } catch (IOException e) { e.printStackTrace(); } } return result; }

2.2. GET请求，带参数，放在header里

/** * 发送HttpGet带参请求 * @param url * @param header * @return */ public static String sendGet(String url, Map header) { HttpGet httpGet = new HttpGet(url); //设置头部 for(Map.Entry entry:header.entrySet()){ httpGet.setHeader(entry.getKey().toString(),entry.getValue().toString()); } CloseableHttpResponse response = null; try { response = httpclient.execute(httpGet); } catch (IOException e1) { e1.printStackTrace(); } String result = null; try { HttpEntity entity = response.getEntity(); if (entity != null) { result = EntityUtils.toString(entity); } } catch (ParseException | IOException e) { e.printStackTrace(); } finally { try { response.close(); } catch (IOException e) { e.printStackTrace(); } } return result; }

2.3. POST请求，不带参数

/** * 发送不带参数的HttpPost请求 * @param url * @return */ public static String sendPost(String url) { HttpPost httppost = new HttpPost(url); CloseableHttpResponse response = null; try { response = httpclient.execute(httppost); } catch (IOException e) { e.printStackTrace(); } HttpEntity entity = response.getEntity(); String result = null; try { result = EntityUtils.toString(entity); } catch (ParseException | IOException e) { e.printStackTrace(); } return result; }

2.4. POST请求，带参数

/** * 发送HttpPost请求，参数为map * @param url * @param map * @return */ public static String sendPost(String url, Map map) { JsonObject jsonObject = new JsonObject(); for(Map.Entry entry:map.entrySet()){ jsonObject.addProperty(entry.getKey().toString(),entry.getValue().toString()); } // 以上循环操作是将 Map对象转化成 JsonObject对象 // System.out.println(jsonObject.toString()); StringEntity entity = new StringEntity(jsonObject.toString(), Consts.UTF_8); HttpPost httppost = new HttpPost(url); httppost.setEntity(entity); //设置请求体 CloseableHttpResponse response = null; try { response = httpclient.execute(httppost); } catch (IOException e) { e.printStackTrace(); } HttpEntity entity1 = response.getEntity(); String result = null; try { result = EntityUtils.toString(entity1); } catch (ParseException | IOException e) { e.printStackTrace(); } return result; } 具体的关键解释，放在代码注释里，如果有什么疑问，咱们再作交流~ 下面，我将完整代码放于下方 package com.example.demo.utils; import java.io.IOException; import java.util.Map; import com.google.gson.JsonObject; import org.apache.http.*; import org.apache.http.clienthods.CloseableHttpResponse; import org.apache.http.clienthods.HttpGet; import org.apache.http.clienthods.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.util.EntityUtils; /** * @author Joe_yoy * */ public class HttpUtil { private static final CloseableHttpClient httpclient = HttpClients.createDefault(); /** * 发送HttpGet请求 * @param url * @return */ public static String sendGet(String url) { HttpGet httpget = new HttpGet(url); CloseableHttpResponse response = null; try { response = httpclient.execute(httpget); } catch (IOException e1) { e1.printStackTrace(); } String result = null; try { HttpEntity entity = response.getEntity(); if (entity != null) { result = EntityUtils.toString(entity); } } catch (ParseException | IOException e) { e.printStackTrace(); } finally { try { response.close(); } catch (IOException e) { e.printStackTrace(); } } return result; } /** * 发送HttpGet带参请求 * @param url * @param header * @return */ public static String sendGet(String url, Map header) { HttpGet httpGet = new HttpGet(url); //设置头部 for(Map.Entry entry:header.entrySet()){ // System.out.println(entry.getKey()+ "###########" + entry.getValue()); httpGet.setHeader(entry.getKey().toString(),entry.getValue().toString()); } // System.out.println(jsonObject.toString()); // HttpGet httpget = new HttpGet(url); CloseableHttpResponse response = null; try { response = httpclient.execute(httpGet); } catch (IOException e1) { e1.printStackTrace(); } String result = null; try { HttpEntity entity = response.getEntity(); if (entity != null) { result = EntityUtils.toString(entity); } } catch (ParseException | IOException e) { e.printStackTrace(); } finally { try { response.close(); } catch (IOException e) { e.printStackTrace(); } } return result; } /** * 发送HttpPost请求，参数为map * @param url * @param map * @return */ public static String sendPost(String url, Map map) { // JsonObject formparams = new JsonObject(); // for (Map.Entry entry : map.entrySet()) { // formparams.add(entry.getKey(), entry.getValue(); // } //json 格式 // UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, Consts.UTF_8); JsonObject jsonObject = new JsonObject(); for(Map.Entry entry:map.entrySet()){ // System.out.println(entry.getKey()+ "###########" + entry.getValue()); jsonObject.addProperty(entry.getKey().toString(),entry.getValue().toString()); } // System.out.println(jsonObject.toString()); StringEntity entity = new StringEntity(jsonObject.toString(), Consts.UTF_8); HttpPost httppost = new HttpPost(url); httppost.setEntity(entity); CloseableHttpResponse response = null; try { response = httpclient.execute(httppost); } catch (IOException e) { e.printStackTrace(); } HttpEntity entity1 = response.getEntity(); String result = null; try { result = EntityUtils.toString(entity1); } catch (ParseException | IOException e) { e.printStackTrace(); } return result; } /** * 发送不带参数的HttpPost请求 * @param url * @return */ public static String sendPost(String url) { HttpPost httppost = new HttpPost(url); CloseableHttpResponse response = null; try { response = httpclient.execute(httppost); } catch (IOException e) { e.printStackTrace(); } HttpEntity entity = response.getEntity(); String result = null; try { result = EntityUtils.toString(entity); } catch (ParseException | IOException e) { e.printStackTrace(); } return result; } }

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