Java調用實現調用http請求的幾種常見方式

Java項目中調用第三方接口的幾種方式：

通過JDK網絡類 java.net.HttpURLConnection
通過common封裝好的 HttpClient
通過Apache封裝好的CloseableHttpClient
通過SpringBoot-RestTemplate

通過JDK網絡類 java.net.HttpURLConnection

實現過程：
Get：
1. 創建遠程連接
2. 設置連接方式
3. 設置連接超時時間
4. 設置響應讀取時間
5. 發起請求
6. 獲取請求數據
7. 關閉連接

Post：
1. 創建遠程連接
2. 設置連接方式
3. 設置連接超時時間
4. 設置響應讀取時間
5. 當向遠程服務器傳送數據/寫數據時，需設置爲 true （setDoOutput）
6. 當向遠程服務器讀取數據時，設置爲true， 該參數可有可無 （setDoInput）
7. 設置傳入參數的格式：（setRequestProperty）
8. 設置鑑權信息：Authorization：（setRequestProperty）
9. 設置參數
10. 發起請求
11. 獲取請求數據
12. 關閉連接

代碼：

package com.riemann.springbootdemo.util.common.httpConnectionUtil;

import org.springframework.lang.Nullable;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * @author riemann
 * @date 2019/05/24 23:42
 */
public class HttpURLConnectionUtil {

    /**
     * Http get請求
     * @param httpUrl 連接
     * @return 響應數據
     */
    public static String doGet(String httpUrl){
        //鏈接
        HttpURLConnection connection = null;
        InputStream is = null;
        BufferedReader br = null;
        StringBuffer result = new StringBuffer();
        try {
            //創建連接
            URL url = new URL(httpUrl);
            connection = (HttpURLConnection) url.openConnection();
            //設置請求方式
            connection.setRequestMethod("GET");
            //設置連接超時時間
            connection.setReadTimeout(15000);
            //開始連接
            connection.connect();
            //獲取響應數據
            if (connection.getResponseCode() == 200) {
                //獲取返回的數據
                is = connection.getInputStream();
                if (null != is) {
                    br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                    String temp = null;
                    while (null != (temp = br.readLine())) {
                        result.append(temp);
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != is) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            //關閉遠程連接
            connection.disconnect();
        }
        return result.toString();
    }

    /**
     * Http post請求
     * @param httpUrl 連接
     * @param param 參數
     * @return
     */
    public static String doPost(String httpUrl, @Nullable String param) {
        StringBuffer result = new StringBuffer();
        //連接
        HttpURLConnection connection = null;
        OutputStream os = null;
        InputStream is = null;
        BufferedReader br = null;
        try {
            //創建連接對象
            URL url = new URL(httpUrl);
            //創建連接
            connection = (HttpURLConnection) url.openConnection();
            //設置請求方法
            connection.setRequestMethod("POST");
            //設置連接超時時間
            connection.setConnectTimeout(15000);
            //設置讀取超時時間
            connection.setReadTimeout(15000);
            //DoOutput設置是否向httpUrlConnection輸出，DoInput設置是否從httpUrlConnection讀入，此外發送post請求必須設置這兩個
            //設置是否可讀取
            connection.setDoOutput(true);
            connection.setDoInput(true);
            //設置通用的請求屬性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            connection.setRequestProperty("Content-Type", "application/json;charset=utf-8");

            //拼裝參數
            if (null != param && param.equals("")) {
                //設置參數
                os = connection.getOutputStream();
                //拼裝參數
                os.write(param.getBytes("UTF-8"));
            }
            //設置權限
            //設置請求頭等
            //開啓連接
            connection.connect();
            //讀取響應
            if (connection.getResponseCode() == 200) {
                is = connection.getInputStream();
                if (null != is) {
                    br = new BufferedReader(new InputStreamReader(is, "GBK"));
                    String temp = null;
                    while (null != (temp = br.readLine())) {
                        result.append(temp);
                        result.append("\r\n");
                    }
                }
            }

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //關閉連接
            if(br!=null){
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(os!=null){
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(is!=null){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            //關閉連接
            connection.disconnect();
        }
        return result.toString();
    }

    public static void main(String[] args) {
        String message = doPost("https://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "");
        System.out.println(message);
    }
}

通過apache common 封裝好的 HttpClient

步驟：
1. 生成一個 HttpClient 對象並設置相應的參數
2. 生成一個GetMethod對象或PostMethod並設置響應的參數
3. 用HttpClient生成的對象來執行GetMethod生成的Get方法
4. 處理響應狀態碼
5. 若響應正常，處理Http響應內容
6. 釋放連接

導入jar包：

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

<!--fastjson-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.32</version>
</dependency>

代碼實現：

package com.riemann.springbootdemo.util.common.httpConnectionUtil;

import com.alibaba.fastjson.JSONObject;
import org.apache.commons.httpclient.*;
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;

/**
 * @author riemann
 * @date 2019/05/25 0:58
 */
public class HttpClientUtil {
    /**
     * httpClient的get請求方式
     * 使用GetMethod來訪問一個URL對應的網頁實現步驟：
     * 1.生成一個HttpClient對象並設置相應的參數；
     * 2.生成一個GetMethod對象並設置響應的參數；
     * 3.用HttpClient生成的對象來執行GetMethod生成的Get方法；
     * 4.處理響應狀態碼；
     * 5.若響應正常，處理HTTP響應內容；
     * 6.釋放連接。
     * @param url
     * @param charset
     * @return
     */
    public static String doGet(String url, String charset) {
        //1.生成HttpClient對象並設置參數
        HttpClient httpClient = new HttpClient();
        //設置Http連接超時爲5秒
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);
        //2.生成GetMethod對象並設置參數
        GetMethod getMethod = new GetMethod(url);
        //設置get請求超時爲5秒
        getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);
        //設置請求重試處理，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.執行HTTP GET 請求
        try {
            int statusCode = httpClient.executeMethod(getMethod);
            //4.判斷訪問的狀態碼
            if (statusCode != HttpStatus.SC_OK) {
                System.err.println("請求出錯：" + getMethod.getStatusLine());
            }
            //5.處理HTTP響應內容
            //HTTP響應頭部信息，這裏簡單打印
            Header[] headers = getMethod.getResponseHeaders();
            for(Header h : headers) {
                System.out.println(h.getName() + "---------------" + h.getValue());
            }
            //讀取HTTP響應內容，這裏簡單打印網頁內容
            //讀取爲字節數組
            byte[] responseBody = getMethod.getResponseBody();
            response = new String(responseBody, charset);
            System.out.println("-----------response:" + response);
            //讀取爲InputStream，在網頁內容數據量大時候推薦使用
            //InputStream response = getMethod.getResponseBodyAsStream();
        } catch (HttpException e) {
            //發生致命的異常，可能是協議不對或者返回的內容有問題
            System.out.println("請檢查輸入的URL!");
            e.printStackTrace();
        } catch (IOException e) {
            //發生網絡異常
            System.out.println("發生網絡異常!");
        } 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");
        //設置json格式傳送
        postMethod.addRequestHeader("Content-Type", "application/json;charset=GBK");
        //必須設置下面這個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
        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) {
        System.out.println(doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "GBK"));
        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");
        System.out.println(doPost("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", jsonObject));
    }
}

通過Apache 封裝好的 CloseableHttpClient

CloseableHttpClient 是在 HttpClient 的基礎上修改更新而來的。

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

<!--fastjson-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.32</version>
</dependency>

package com.riemann.springbootdemo.util.common.httpConnectionUtil;

import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
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.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

/**
 * @author riemann
 * @date 2019/05/25 1:35
 */
public class CloseableHttpClientUtil {

    private static String tokenString = "";
    private static String AUTH_TOKEN_EXPIRED = "AUTH_TOKEN_EXPIRED";
    private static CloseableHttpClient httpClient = null;

    /**
     * 以get方式調用第三方接口
     * @param url
     * @param token
     * @return
     */
    public static String doGet(String url, String token) {
        //創建HttpClient對象
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        HttpGet httpGet = new HttpGet(url);
        if (null != tokenString && !tokenString.equals("")) {
            tokenString = getToken();
        }
        //api_gateway_auth_token自定義header頭，用於token驗證使用
        httpGet.addHeader("api_gateway_auth_token",tokenString);
        httpGet.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");
        try {
            HttpResponse response = httpClient.execute(httpGet);
            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方式調用第三方接口
     * @param url
     * @param json
     * @return
     */
    public static String doPost(String url, JSONObject json) {
        if (null == httpClient) {
            httpClient = HttpClientBuilder.create().build();
        }
        HttpPost httpPost = new HttpPost(url);
        if (null != tokenString && tokenString.equals("")) {
            tokenString = getToken();
        }
        //api_gateway_auth_token自定義header頭，用於token驗證使用
        httpPost.addHeader("api_gateway_auth_token", tokenString);
        httpPost.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");
        try {
            StringEntity se = new StringEntity(json.toString());
            se.setContentEncoding("UTF-8");
            //發送json數據需要設置contentType
            se.setContentType("application/x-www-form-urlencoded");
            //設置請求參數
            httpPost.setEntity(se);
            HttpResponse response = httpClient.execute(httpPost);
            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();
        } 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");
        if (null == httpClient) {
            httpClient = HttpClientBuilder.create().build();
        }
        HttpPost httpPost = new HttpPost("http://localhost/login");
        httpPost.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");
        try {
            StringEntity se = new StringEntity(object.toString());
            se.setContentEncoding("UTF-8");
            //發送json數據需要設置contentType
            se.setContentType("application/x-www-form-urlencoded");
            //設置請求參數
            httpPost.setEntity(se);
            HttpResponse response = httpClient.execute(httpPost);
            //這裏可以把返回的結果按照自定義的返回數據結果，把string轉換成自定義類
            //ResultTokenBO result = JSONObject.parseObject(response, ResultTokenBO.class);
            //把response轉爲jsonObject
            JSONObject result = (JSONObject) JSONObject.parseObject(String.valueOf(response));
            if (result.containsKey("token")) {
                token = result.getString("token");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return token;
    }

    /**
     * 測試
     */
    public static void test(String telephone) {

        JSONObject object = new JSONObject();
        object.put("telephone", telephone);

        //首先獲取token
        tokenString = getToken();
        String response = doPost("http://localhost/searchUrl", object);
        //如果返回的結果是list形式的，需要使用JSONObject.parseArray轉換
        //List<Result> list = JSONObject.parseArray(response, Result.class);
        System.out.println(response);
    }

    public static void main(String[] args) {
        test("12345678910");
    }
}

通過SpringBoot-RestTemplate

springBoot-RestTemplate 是上面三種方式的集大成者，代碼編寫更加簡單，目前可以採用的調用第三方接口有：

delete() 在特定的URL上對資源執行HTTP DELETE操作
exchange() 在URL上執行特定的HTTP方法，返回包含對象的ResponseEntity，這個對象是從響應體中映射得到的
execute() 在URL上執行特定的HTTP方法，返回一個從響應體映射得到的對象
getForEntity() 發送一個HTTP GET請求，返回的ResponseEntity包含了響應體所映射成的對象
getForObject() 發送一個HTTP GET請求，返回的請求體將映射爲一個對象
postForEntity() POST 數據到一個URL，返回包含一個對象的ResponseEntity，這個對象是從響應體中映射得到的
postForObject() POST 數據到一個URL，返回根據響應體匹配形成的對象
headForHeaders() 發送HTTP HEAD請求，返回包含特定資源URL的HTTP頭
optionsForAllow() 發送HTTP OPTIONS請求，返回對特定URL的Allow頭信息
postForLocation() POST 數據到一個URL，返回新創建資源的URL
put() PUT 資源到特定的URL

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
    </parent>

    <dependencies>
        <!--CloseableHttpClient-->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>

        <!--spring restTemplate-->
        <!-- @ConfigurationProperties annotation processing (metadata for IDEs)
                生成spring-configuration-metadata.json類，需要引入此類-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

在啓動類同包下創建RestTemplateConfig.java 類

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;

/**
 * @author riemann
 * @date 2019/05/25 2:16
 */
@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;
    }
}

然後在Service類（RestTemplateToInterface）中注入使用

import com.alibaba.fastjson.JSONObject;
import com.swordfall.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.*;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

/**
 * @author riemann
 * @date 2019/05/25 2:20
 */
@Service
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
        HttpHeaders headers = new HttpHeaders();
        String token = "asdfaf2322";
        headers.add("authorization", token);
        headers.setContentType(MediaType.APPLICATION_JSON);

        //放入body中的json參數
        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;
    }
}

Java調用實現調用http請求的幾種常見方式

通過JDK網絡類 java.net.HttpURLConnection

通過apache common 封裝好的 HttpClient

通過Apache 封裝好的 CloseableHttpClient

通過SpringBoot-RestTemplate

nginx 路由匹配規則

nginx 小功能

Java實現http請求的幾種常見方式

資深架構師成長路線 -- 設計思想解讀開源框架

Java 基礎篇

Mac下配置sublime實現LaTeX

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

linux以太網驅動總結