import com.alibaba.fastjson.JSON;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
 
/**
 * @ClassName : HttpUrlConnectionToInterface
 * @Description : jdk類HttpURLConnection調(diào)用第三方http接口
 * @Author : THQ
 * @Date: 2021-09-02 14:09
 * @Version V1.0
 */
public class HttpUrlConnectionToInterface {
 
    /**
     * 以post方式調(diào)用對方接口方法
     * @param pathUrl
     */
    public static void doPost(String pathUrl, String data){
        OutputStreamWriter out = null;
        BufferedReader br = null;
        String result = "";
        try {
            URL url = new URL(pathUrl);
 
            //打開和url之間的連接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 
            //設(shè)定請求的方法為"POST"，默認是GET
            //post與get的不同之處在于post的參數(shù)不是放在URL字串里面，而是放在http請求的正文內(nèi)。
            conn.setRequestMethod("POST");
 
            //設(shè)置30秒連接超時
            conn.setConnectTimeout(30000);
            //設(shè)置30秒讀取超時
            conn.setReadTimeout(30000);
 
            // 設(shè)置是否向httpUrlConnection輸出，因為這個是post請求，參數(shù)要放在http正文內(nèi)，因此需要設(shè)為true, 默認情況下是false;
            conn.setDoOutput(true);
            // 設(shè)置是否從httpUrlConnection讀入，默認情況下是true;
            conn.setDoInput(true);
 
            // Post請求不能使用緩存
            conn.setUseCaches(false);
 
            //設(shè)置通用的請求屬性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");  //維持長鏈接
            conn.setRequestProperty("Content-Type", "application/json;charset=utf-8");
 
            //連接，從上述url.openConnection()至此的配置必須要在connect之前完成，
            conn.connect();
 
            /**
             * 下面的三句代碼，就是調(diào)用第三方http接口
             */
            //獲取URLConnection對象對應(yīng)的輸出流
            //此處getOutputStream會隱含的進行connect(即：如同調(diào)用上面的connect()方法，所以在開發(fā)中不調(diào)用上述的connect()也可以)。
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            //發(fā)送請求參數(shù)即數(shù)據(jù)
            out.write(data);
            //flush輸出流的緩沖
            out.flush();
 
            /**
             * 下面的代碼相當于，獲取調(diào)用第三方http接口后返回的結(jié)果
             */
            //獲取URLConnection對象對應(yīng)的輸入流
            InputStream is = conn.getInputStream();
            //構(gòu)造一個字符流緩存
            br = new BufferedReader(new InputStreamReader(is));
            String str = "";
            while ((str = br.readLine()) != null){
                result += str;
            }
            System.out.println(result);
            //關(guān)閉流
            is.close();
            //斷開連接，disconnect是在底層tcp socket鏈接空閑時才切斷，如果正在被其他線程使用就不切斷。
            conn.disconnect();
 
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                if (out != null){
                    out.close();
                }
                if (br != null){
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
    /**
     * 以get方式調(diào)用對方接口方法
     * @param pathUrl
     */
    public static void doGet(String pathUrl){
        BufferedReader br = null;
        String result = "";
        try {
            URL url = new URL(pathUrl);
 
            //打開和url之間的連接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 
            //設(shè)定請求的方法為"GET"，默認是GET
            //post與get的不同之處在于post的參數(shù)不是放在URL字串里面，而是放在http請求的正文內(nèi)。
            conn.setRequestMethod("GET");
 
            //設(shè)置30秒連接超時
            conn.setConnectTimeout(30000);
            //設(shè)置30秒讀取超時
            conn.setReadTimeout(30000);
 
            // 設(shè)置是否向httpUrlConnection輸出，因為這個是post請求，參數(shù)要放在http正文內(nèi)，因此需要設(shè)為true, 默認情況下是false;
            conn.setDoOutput(true);
            // 設(shè)置是否從httpUrlConnection讀入，默認情況下是true;
            conn.setDoInput(true);
 
            // Post請求不能使用緩存(get可以不使用)
            conn.setUseCaches(false);
 
            //設(shè)置通用的請求屬性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");  //維持長鏈接
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
 
            //連接，從上述url.openConnection()至此的配置必須要在connect之前完成，
            conn.connect();
 
            /**
             * 下面的代碼相當于，獲取調(diào)用第三方http接口后返回的結(jié)果
             */
            //獲取URLConnection對象對應(yīng)的輸入流
            InputStream is = conn.getInputStream();
            //構(gòu)造一個字符流緩存
            br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
            String str = "";
            while ((str = br.readLine()) != null){
                result += str;
            }
            System.out.println(result);
            //關(guān)閉流
            is.close();
            //斷開連接，disconnect是在底層tcp socket鏈接空閑時才切斷，如果正在被其他線程使用就不切斷。
            conn.disconnect();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                if (br != null){
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
    public static void main(String[] args) {
        //post請求一般都是把實體對象轉(zhuǎn)為Json字符串
        LocationPrintDTO locationPrintDTO = new LocationPrintDTO();
        String s = JSON.toJSONString(locationPrintDTO);
        doPost("http://127.0.0.1:9090/ZebraPrinter/locationPrint", s);
        doGet("https://weather.cma.cn/api/climate?stationid=57516");
    }
}

        <!--HttpClient-->
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>

import com.alibaba.fastjson.JSONObject;
import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
 
import java.io.IOException;
 
/**
 * @ClassName : HttpClientToInterface
 * @Description : HttpClient模擬get、post請求并發(fā)送請求參數(shù)（json等）
 * @Author : THQ
 * @Date: 2021-09-02 16:50
 * @Version V1.0
 */
public class HttpClientToInterface {
 
    /**
     * httpClient的get請求方式
     * 使用GetMethod來訪問一個URL對應(yīng)的網(wǎng)頁實現(xiàn)步驟：
     * 1.生成一個HttpClient對象并設(shè)置相應(yīng)的參數(shù)；
     * 2.生成一個GetMethod對象并設(shè)置響應(yīng)的參數(shù)；
     * 3.用HttpClient生成的對象來執(zhí)行GetMethod生成的Get方法；
     * 4.處理響應(yīng)狀態(tài)碼；
     * 5.若響應(yīng)正常，處理HTTP響應(yīng)內(nèi)容；
     * 6.釋放連接。
     * @param url
     * @param charset
     * @return
     */
    public static String doGet(String url, String charset){
        /**
         * 1.生成HttpClient對象并設(shè)置參數(shù)
         */
        HttpClient httpClient = new HttpClient();
        //設(shè)置Http連接超時為5秒
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);
 
        /**
         * 2.生成GetMethod對象并設(shè)置參數(shù)
         */
        GetMethod getMethod = new GetMethod(url);
        //設(shè)置get請求超時為5秒
        getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);
        //設(shè)置請求重試處理，用的是默認的重試處理：請求三次
        getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());
 
        String response = "";
 
        /**
         * 3.執(zhí)行HTTP GET 請求
         */
        try {
            int statusCode = httpClient.executeMethod(getMethod);
 
            /**
             * 4.判斷訪問的狀態(tài)碼
             */
            if (statusCode != HttpStatus.SC_OK){
                System.err.println("請求出錯：" + getMethod.getStatusLine());
            }
 
            /**
             * 5.處理HTTP響應(yīng)內(nèi)容
             */
            //HTTP響應(yīng)頭部信息，這里簡單打印
            Header[] headers = getMethod.getResponseHeaders();
            for (Header h: headers){
                System.out.println(h.getName() + "---------------" + h.getValue());
            }
            //讀取HTTP響應(yīng)內(nèi)容，這里簡單打印網(wǎng)頁內(nèi)容
            //讀取為字節(jié)數(shù)組
            byte[] responseBody = getMethod.getResponseBody();
            response = new String(responseBody, charset);
            System.out.println("-----------response:" + response);
            //讀取為InputStream，在網(wǎng)頁內(nèi)容數(shù)據(jù)量大時候推薦使用
            //InputStream response = getMethod.getResponseBodyAsStream();
 
        } catch (HttpException e) {
            //發(fā)生致命的異常，可能是協(xié)議不對或者返回的內(nèi)容有問題
            System.out.println("請檢查輸入的URL!");
            e.printStackTrace();
        } catch (IOException e){
            //發(fā)生網(wǎng)絡(luò)異常
            System.out.println("發(fā)生網(wǎng)絡(luò)異常!");
        }finally {
            /**
             * 6.釋放連接
             */
            getMethod.releaseConnection();
        }
        return response;
    }
 
    /**
     * post請求
     * @param url
     * @param json
     * @return
     */
    public static String doPost(String url, JSONObject json){
        HttpClient httpClient = new HttpClient();
        PostMethod postMethod = new PostMethod(url);
 
        postMethod.addRequestHeader("accept", "*/*");
        postMethod.addRequestHeader("connection", "Keep-Alive");
        //設(shè)置json格式傳送
        postMethod.addRequestHeader("Content-Type", "application/json;charset=utf-8");
        //必須設(shè)置下面這個Header
        postMethod.addRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
        //添加請求參數(shù)
        postMethod.addParameter("commentId", json.getString("commentId"));
 
        String res = "";
        try {
            int code = httpClient.executeMethod(postMethod);
            if (code == 200){
                res = postMethod.getResponseBodyAsString();
                System.out.println(res);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return res;
    }
 
    public static void main(String[] args) {
        doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "UTF-8");
        System.out.println("-----------分割線------------");
        System.out.println("-----------分割線------------");
        System.out.println("-----------分割線------------");
 
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("commentId", "13026194071");
        doPost("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm", jsonObject);
    }
}

        <!--CloseableHttpClient-->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.28</version>
        </dependency>

import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
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.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
 
import java.io.IOException;
 
/**
 * @ClassName : CloseableHttpClientToInterface
 * @Description : Apache封裝好的CloseableHttpClient
 * @Author : THQ
 * @Date: 2021-09-02 17:16
 * @Version V1.0
 */
public class CloseableHttpClientToInterface {
    private static String tokenString = "";
    private static String AUTH_TOKEN_EXPIRED = "AUTH_TOKEN_EXPIRED";
    private static CloseableHttpClient httpClient = null;
 
    /**
     * 以get方式調(diào)用第三方接口
     * @param url
     * @return
     */
    public static String doGet(String url, String token){
        //創(chuàng)建HttpClient對象
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        HttpGet get = new HttpGet(url);
 
        try {
            if (tokenString != null && !tokenString.equals("")){
                tokenString = getToken();
            }
            //api_gateway_auth_token自定義header頭，用于token驗證使用
            get.addHeader("api_gateway_auth_token", tokenString);
            get.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
            HttpResponse response = httpClient.execute(get);
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
                //返回json格式
                String res = EntityUtils.toString(response.getEntity());
                return res;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
 
    /**
     * 以post方式調(diào)用第三方接口
     * @param url
     * @param json
     * @return
     */
    public static String doPost(String url, JSONObject json){
 
        try {
            if (httpClient == null){
                httpClient = HttpClientBuilder.create().build();
            }
 
            HttpPost post = new HttpPost(url);
 
            if (tokenString != null && !tokenString.equals("")){
                tokenString = getToken();
            }
 
            //api_gateway_auth_token自定義header頭，用于token驗證使用
            post.addHeader("api_gateway_auth_token", tokenString);
            post.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
 
            StringEntity s = new StringEntity(json.toString());
            s.setContentEncoding("UTF-8");
            //發(fā)送json數(shù)據(jù)需要設(shè)置contentType
            s.setContentType("application/x-www-form-urlencoded");
            //設(shè)置請求參數(shù)
            post.setEntity(s);
            HttpResponse response = httpClient.execute(post);
 
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
                //返回json格式
                String res = EntityUtils.toString(response.getEntity());
                return res;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if (httpClient != null){
                try {
                    httpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }
 
    /**
     * 獲取第三方接口的token
     */
    public static String getToken(){
 
        String token = "";
 
        JSONObject object = new JSONObject();
        object.put("appid", "appid");
        object.put("secretkey", "secretkey");
 
        try {
            if (httpClient == null){
                httpClient = HttpClientBuilder.create().build();
            }
            HttpPost post = new HttpPost("http://localhost/login");
 
            post.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
 
            StringEntity s = new StringEntity(object.toString());
            s.setContentEncoding("UTF-8");
            //發(fā)送json數(shù)據(jù)需要設(shè)置contentType
            s.setContentType("application/x-www-form-urlencoded");
            //設(shè)置請求參數(shù)
            post.setEntity(s);
            HttpResponse response = httpClient.execute(post);
 
            //這里可以把返回的結(jié)果按照自定義的返回數(shù)據(jù)結(jié)果，把string轉(zhuǎn)換成自定義類
            //ResultTokenBO result = JSONObject.parseObject(response, ResultTokenBO.class);
 
            //把response轉(zhuǎn)為jsonObject
            JSONObject result = JSONObject.parseObject(String.valueOf(response));
            if (result.containsKey("token")){
                token = result.getString("token");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return token;
    }
 
    /**
     * 測試
     */
    public static void test(String telephone){
 
        JSONObject object = new JSONObject();
        object.put("telephone", telephone);
 
        try {
            //首先獲取token
            tokenString = getToken();
            String response = doPost("http://localhost/searchUrl", object);
 
            //如果返回的結(jié)果是list形式的，需要使用JSONObject.parseArray轉(zhuǎn)換
            //List<Result> list = JSONObject.parseArray(response, Result.class);
 
            System.out.println(response);
 
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    public static void main(String[] args) {
        test("12345678910");
    }

        <!--okhttp3-->
        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>4.9.1</version>
        </dependency>

import okhttp3.*;
 
import java.io.IOException;
 
/**
 * @ClassName : OkHttpToInterface
 * @Description :
 * @Author : THQ
 * @Date: 2021-09-02 17:36
 * @Version V1.0
 */
public class OkHttpToInterface {
 
    public static final MediaType JSON = MediaType.get("application/json; charset=utf-8");
 
    /**
     * 以get方式調(diào)用第三方接口
     * @param url
     */
    public static void doGet(String url) {
        OkHttpClient okHttpClient = new OkHttpClient();
        final Request request = new Request.Builder()
                .url(url)
                .get()//默認就是GET請求，可以不寫
                .build();
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                System.out.println( "onFailure: ");
            }
 
            @Override
            public void onResponse(Call call, Response response) throws IOException {
                System.out.println("onResponse: " + response.body().string());
            }
        });
    }
 
    /**
     * post請求
     * @param url
     * @param json
     */
    public static void doPost(String url, String json){
        MediaType mediaType = MediaType.parse("text/x-markdown; charset=utf-8");
        String requestBody = json;
        Request request = new Request.Builder()
                .url(url)
                .post(RequestBody.create(mediaType, requestBody))
                .build();
        OkHttpClient okHttpClient = new OkHttpClient();
        okHttpClient.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                System.out.println("onFailure: " + e.getMessage());
            }
 
            @Override
            public void onResponse(Call call, Response response) throws IOException {
                System.out.println(response.protocol() + " " +response.code() + " " + response.message());
                Headers headers = response.headers();
                for (int i = 0; i < headers.size(); i++) {
                    System.out.println(headers.name(i) + ":" + headers.value(i));
                }
                System.out.println("onResponse: " + response.body().string());
            }
        });
    }
 
    public static void main(String[] args) {
        doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071");
        doPost("https://api.github.com/markdown/raw","I am Jdqm.");
    }
}

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
    </parent>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;
 
/**
 * @ClassName : RestTemplateConfig 
 * @Description :
 * @Author : THQ
 * @Date: 2021-09-02 20:00
 * @Version V1.0
 */
@Configuration
public class RestTemplateConfig {
 
    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory factory){
        return new RestTemplate(factory);
    }
 
    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory(){
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        factory.setConnectTimeout(15000);
        factory.setReadTimeout(5000);
        return factory;
    }
}

import com.alibaba.fastjson.JSONObject;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.*;
import org.springframework.web.client.RestTemplate;
 
/**
 * @ClassName : RestTemplateToInterface
 * @Description :
 * @Author : THQ
 * @Date: 2021-09-02 20:03
 * @Version V1.0
 */
public class RestTemplateToInterface {
 
    @Autowired
    private RestTemplate restTemplate;
 
    /**
     * 以get方式請求第三方http接口 getForEntity
     * @param url
     * @return
     */
    public User doGetWith1(String url){
        ResponseEntity<User> responseEntity = restTemplate.getForEntity(url, User.class);
        User user = responseEntity.getBody();
        return user;
    }
 
    /**
     * 以get方式請求第三方http接口 getForObject
     * 返回值返回的是響應(yīng)體，省去了我們再去getBody()
     * @param url
     * @return
     */
    public User doGetWith2(String url){
        User user  = restTemplate.getForObject(url, User.class);
        return user;
    }
 
    /**
     * 以post方式請求第三方http接口 postForEntity
     * @param url
     * @return
     */
    public String doPostWith1(String url){
        User user = new User("小白", 20);
        ResponseEntity<String> responseEntity = restTemplate.postForEntity(url, user, String.class);
        String body = responseEntity.getBody();
        return body;
    }
 
    /**
     * 以post方式請求第三方http接口 postForEntity
     * @param url
     * @return
     */
    public String doPostWith2(String url){
        User user = new User("小白", 20);
        String body = restTemplate.postForObject(url, user, String.class);
        return body;
    }
 
    /**
     * exchange
     * @return
     */
    public String doExchange(String url, Integer age, String name){
        //header參數(shù)
        HttpHeaders headers = new HttpHeaders();
        String token = "asdfaf2322";
        headers.add("authorization", token);
        headers.setContentType(MediaType.APPLICATION_JSON);
 
        //放入body中的json參數(shù)
        JSONObject obj = new JSONObject();
        obj.put("age", age);
        obj.put("name", name);
 
        //組裝
        HttpEntity<JSONObject> request = new HttpEntity<>(obj, headers);
        ResponseEntity<String> responseEntity = restTemplate.exchange(url, HttpMethod.POST, request, String.class);
        String body = responseEntity.getBody();
        return body;
    }
 
}

        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.7.1</version>
        </dependency>

import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.CharsetUtil;
import cn.hutool.http.HttpUtil;
 
import java.util.HashMap;
 
/**
 * @ClassName : HttpUtilToInterface
 * @Description :
 * @Author : THQ
 * @Date: 2021-09-02 20:15
 * @Version V1.0
 */
public class HttpUtilToInterface {
 
    /**
     * get請求示例
     */
    public static void doGet() {
        // 最簡單的HTTP請求，可以自動通過header等信息判斷編碼，不區(qū)分HTTP和HTTPS
        String result1 = HttpUtil.get("https://www.baidu.com");
 
        // 當無法識別頁面編碼的時候，可以自定義請求頁面的編碼
        String result2 = HttpUtil.get("https://www.baidu.com", CharsetUtil.CHARSET_UTF_8);
 
        //可以單獨傳入http參數(shù)，這樣參數(shù)會自動做URL編碼，拼接在URL中
        HashMap<String, Object> paramMap = new HashMap<>();
        paramMap.put("city", "北京");
        String result3 = HttpUtil.get("https://www.baidu.com", paramMap);
    }
 
    /**
     * post請求示例
     */
    public static void doPost() {
        //post普通請求示例
        HashMap<String, Object> paramMap = new HashMap<>();
        paramMap.put("city", "北京");
        String result= HttpUtil.post("https://www.baidu.com", paramMap);
 
        //文件上傳示例
        HashMap<String, Object> paramMap1 = new HashMap<>();
        //文件上傳只需將參數(shù)中的鍵指定（默認file），值設(shè)為文件對象即可，對于使用者來說，文件上傳與普通表單提交并無區(qū)別
        paramMap1.put("file", FileUtil.file("D:\\face.jpg"));
        String result1= HttpUtil.post("https://www.baidu.com", paramMap1);
 
        //下載文件（很少用）
        String fileUrl = "http://mirrors.sohu.com/centos/8.4.2105/isos/x86_64/CentOS-8.4.2105-x86_64-dvd1.iso";
        //將文件下載后保存在E盤，返回結(jié)果為下載文件大小
        long size = HttpUtil.downloadFile(fileUrl, FileUtil.file("e:/"));
        System.out.println("Download size: " + size);
    }
}