HttpClient请求工具类

 package com.yangche.utils;

 import org.apache.http.NameValuePair;
 import org.apache.http.client.ClientProtocolException;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
 import org.apache.http.client.methods.*;
 import org.apache.http.client.utils.URIBuilder;
 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.message.BasicNameValuePair;
 import org.apache.http.util.EntityUtils;
 import org.springframework.util.StringUtils;

 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;

 public class HttpClientUtil {
     public static String doGet(String url, Map<String,Object> param){
         //创建httpclient对象
         CloseableHttpClient httpClient = HttpClients.createDefault();
         String resultString="";
         CloseableHttpResponse response=null;
         try {
             URIBuilder builder=new URIBuilder(url);
             if(param!=null){
                 for (String key:param.keySet()){
                     if(param.get(key) instanceof List){
                         List list=(List)param.get(key);
                         for (Object liString:list){
                             builder.addParameter(key,String.valueOf(liString));
                         }
                     }else {
                         builder.addParameter(key,String.valueOf(param.get(key)));
                     }
                 }
             }
             URI uri=builder.build();
             //创建httpGet请求
             HttpGet httpGet=new HttpGet(uri);
             //执行请求
             response=httpClient.execute(httpGet);
             resultString= EntityUtils.toString(response.getEntity(),"UTF-8");
         } catch (URISyntaxException e) {
             e.printStackTrace();
         } catch (ClientProtocolException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }finally {
             try {
                 if(response!=null){
                     response.close();
                 }
                 httpClient.close();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return resultString;
     }
     public static String doGet(String url){
         return doGet(url,null);
     }
     public static String doPost(String url,Map<String,String> param){
         //创建httpclient对象
         CloseableHttpClient httpClient = HttpClients.createDefault();
         CloseableHttpResponse response=null;
         String resultString="";
         //创建httpPost请求
         HttpPost httpPost = new HttpPost(url);
         //创建参数列表
         if(param!=null){
             List<NameValuePair> paramList=new ArrayList<>();
             for (String key:param.keySet()){
                 paramList.add(new BasicNameValuePair(key,param.get(key)));
             }
             try {
                 //模拟表单
                 UrlEncodedFormEntity entity=new UrlEncodedFormEntity(paramList);
                 httpPost.setEntity(entity);
                 //执行http请求
                 response=httpClient.execute(httpPost);
                 resultString=EntityUtils.toString(response.getEntity(),"UTF-8");
             } catch (UnsupportedEncodingException e) {
                 e.printStackTrace();
             } catch (ClientProtocolException e) {
                 e.printStackTrace();
             } catch (IOException e) {
                 e.printStackTrace();
             }finally {
                 try {
                     response.close();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
             }
         }
         return resultString;
     }
     public static String doPost(String url){
         return doPost(url,null);
     }

     /**
      * restful请求
      * @param url
      * @param requestType 请求类型：post、delete、patch
      * @param json
      * @return
      */
     public static String doRequest(String url,String requestType,String json){
         //创建HttpClient对象
         CloseableHttpClient httpClient=HttpClients.createDefault();
         CloseableHttpResponse response=null;
         String resultString="";
         try {
             //创建不同类型的请求
             HttpPost httpPost=new HttpPost(url);
             HttpDeleteWithBody httpDelete =new HttpDeleteWithBody(url);
             HttpPatch httpPatch=new HttpPatch(url);
             //创建请求内容
             StringEntity entity=new StringEntity(json, ContentType.APPLICATION_JSON);
             //执行http请求
             if(!StringUtils.isEmpty(requestType)&&requestType.equalsIgnoreCase("post")){
                 httpPost.setEntity(entity);
                 response=httpClient.execute(httpPost);
             }else if(!StringUtils.isEmpty(requestType)&&requestType.equalsIgnoreCase("delete")){
                 httpDelete.setEntity(entity);
                 response=httpClient.execute(httpDelete);
             }else if(!StringUtils.isEmpty(requestType)&&requestType.equalsIgnoreCase("patch")){
                 httpPatch.setEntity(entity);
                 response=httpClient.execute(httpPatch);
             }
             resultString=EntityUtils.toString(response.getEntity(),"UTF-8");
         } catch (IOException e) {
             e.printStackTrace();
         } finally {
             try {
                 response.close();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return resultString;
     }

     private static class HttpDeleteWithBody extends HttpEntityEnclosingRequestBase {
         public static final String METHOD_NAME="DELETE";
         @Override
         public String getMethod() {
             return METHOD_NAME;
         }
         public HttpDeleteWithBody (final String uri){
             super();
             setURI(URI.create(uri));
         }
         public HttpDeleteWithBody (final URI uri){
             super();
             setURI(uri);
         }
         public HttpDeleteWithBody(){
             super();
         }
     }
 }

以上所需的maven依赖如下：

 <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore -->
 <dependency>
     <groupId>org.apache.httpcomponents</groupId>
     <artifactId>httpcore</artifactId>
     <version>4.4.10</version>
 </dependency>

 <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
 <dependency>
     <groupId>org.apache.httpcomponents</groupId>
     <artifactId>httpclient</artifactId>
     <version>4.5.6</version>
 </dependency>