HttpClient請求工具類

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){
        //建立httpclient物件
        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();
            //建立httpGet請求
            HttpGet httpGet=new HttpGet(uri);
            //執行請求
            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){
        //建立httpclient物件
        CloseableHttpClient httpClient = HttpClients.createDefault();
        CloseableHttpResponse response=null;
        String resultString="";
        //建立httpPost請求
        HttpPost httpPost = new HttpPost(url);
        //建立引數列表
        if(param!=null){
            List<NameValuePair> paramList=new ArrayList<>();
            for (String key:param.keySet()){
                paramList.add(new BasicNameValuePair(key,param.get(key)));
            }
            try {
                //模擬表單
                UrlEncodedFormEntity entity=new UrlEncodedFormEntity(paramList);
                httpPost.setEntity(entity);
                //執行http請求
                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請求
     * @param url
     * @param requestType 請求型別：post、delete、patch
     * @param json
     * @return
     */
    public static String doRequest(String url,String requestType,String json){
        //建立HttpClient物件
        CloseableHttpClient httpClient=HttpClients.createDefault();
        CloseableHttpResponse response=null;
        String resultString="";
        try {
            //建立不同型別的請求
            HttpPost httpPost=new HttpPost(url);
            HttpDeleteWithBody httpDelete =new HttpDeleteWithBody(url);
            HttpPatch httpPatch=new HttpPatch(url);
            //建立請求內容
            StringEntity entity=new StringEntity(json, ContentType.APPLICATION_JSON);
            //執行http請求
            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依賴如下：

<!-- 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>