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詳解java實(shí)現(xiàn)HTTP請(qǐng)求的三種方式

發(fā)布時(shí)間:2020-09-10 10:23:23 來源:腳本之家 閱讀:157 作者:君臨-行者無界 欄目:編程語言

目前JAVA實(shí)現(xiàn)HTTP請(qǐng)求的方法用的最多的有兩種:一種是通過HTTPClient這種第三方的開源框架去實(shí)現(xiàn)。HTTPClient對(duì)HTTP的封裝性比較不錯(cuò),通過它基本上能夠滿足我們大部分的需求,HttpClient3.1 是 org.apache.commons.httpclient下操作遠(yuǎn)程 url的工具包,雖然已不再更新,但實(shí)現(xiàn)工作中使用httpClient3.1的代碼還是很多,HttpClient4.5是org.apache.http.client下操作遠(yuǎn)程 url的工具包,最新的;另一種則是通過HttpURLConnection去實(shí)現(xiàn),HttpURLConnection是JAVA的標(biāo)準(zhǔn)類,是JAVA比較原生的一種實(shí)現(xiàn)方式。

自己在工作中三種方式都用到過,總結(jié)一下分享給大家,也方便自己以后使用,話不多說上代碼。

第一種方式:java原生HttpURLConnection

package com.powerX.httpClient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class HttpClient {
  public static String doGet(String httpurl) {
    HttpURLConnection connection = null;
    InputStream is = null;
    BufferedReader br = null;
    String result = null;// 返回結(jié)果字符串
    try {
      // 創(chuàng)建遠(yuǎn)程url連接對(duì)象
      URL url = new URL(httpurl);
      // 通過遠(yuǎn)程url連接對(duì)象打開一個(gè)連接,強(qiáng)轉(zhuǎn)成httpURLConnection類
      connection = (HttpURLConnection) url.openConnection();
      // 設(shè)置連接方式:get
      connection.setRequestMethod("GET");
      // 設(shè)置連接主機(jī)服務(wù)器的超時(shí)時(shí)間:15000毫秒
      connection.setConnectTimeout(15000);
      // 設(shè)置讀取遠(yuǎn)程返回的數(shù)據(jù)時(shí)間:60000毫秒
      connection.setReadTimeout(60000);
      // 發(fā)送請(qǐng)求
      connection.connect();
      // 通過connection連接,獲取輸入流
      if (connection.getResponseCode() == 200) {
        is = connection.getInputStream();
        // 封裝輸入流is,并指定字符集
        br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
        // 存放數(shù)據(jù)
        StringBuffer sbf = new StringBuffer();
        String temp = null;
        while ((temp = br.readLine()) != null) {
          sbf.append(temp);
          sbf.append("\r\n");
        }
        result = sbf.toString();
      }
    } catch (MalformedURLException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 關(guān)閉資源
      if (null != br) {
        try {
          br.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }

      if (null != is) {
        try {
          is.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }

      connection.disconnect();// 關(guān)閉遠(yuǎn)程連接
    }

    return result;
  }

  public static String doPost(String httpUrl, String param) {

    HttpURLConnection connection = null;
    InputStream is = null;
    OutputStream os = null;
    BufferedReader br = null;
    String result = null;
    try {
      URL url = new URL(httpUrl);
      // 通過遠(yuǎn)程url連接對(duì)象打開連接
      connection = (HttpURLConnection) url.openConnection();
      // 設(shè)置連接請(qǐng)求方式
      connection.setRequestMethod("POST");
      // 設(shè)置連接主機(jī)服務(wù)器超時(shí)時(shí)間:15000毫秒
      connection.setConnectTimeout(15000);
      // 設(shè)置讀取主機(jī)服務(wù)器返回?cái)?shù)據(jù)超時(shí)時(shí)間:60000毫秒
      connection.setReadTimeout(60000);

      // 默認(rèn)值為:false,當(dāng)向遠(yuǎn)程服務(wù)器傳送數(shù)據(jù)/寫數(shù)據(jù)時(shí),需要設(shè)置為true
      connection.setDoOutput(true);
      // 默認(rèn)值為:true,當(dāng)前向遠(yuǎn)程服務(wù)讀取數(shù)據(jù)時(shí),設(shè)置為true,該參數(shù)可有可無
      connection.setDoInput(true);
      // 設(shè)置傳入?yún)?shù)的格式:請(qǐng)求參數(shù)應(yīng)該是 name1=value1&name2=value2 的形式。
      connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
      // 設(shè)置鑒權(quán)信息:Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0
      connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
      // 通過連接對(duì)象獲取一個(gè)輸出流
      os = connection.getOutputStream();
      // 通過輸出流對(duì)象將參數(shù)寫出去/傳輸出去,它是通過字節(jié)數(shù)組寫出的
      os.write(param.getBytes());
      // 通過連接對(duì)象獲取一個(gè)輸入流,向遠(yuǎn)程讀取
      if (connection.getResponseCode() == 200) {

        is = connection.getInputStream();
        // 對(duì)輸入流對(duì)象進(jìn)行包裝:charset根據(jù)工作項(xiàng)目組的要求來設(shè)置
        br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

        StringBuffer sbf = new StringBuffer();
        String temp = null;
        // 循環(huán)遍歷一行一行讀取數(shù)據(jù)
        while ((temp = br.readLine()) != null) {
          sbf.append(temp);
          sbf.append("\r\n");
        }
        result = sbf.toString();
      }
    } catch (MalformedURLException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 關(guān)閉資源
      if (null != br) {
        try {
          br.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      if (null != os) {
        try {
          os.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      if (null != is) {
        try {
          is.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      // 斷開與遠(yuǎn)程地址url的連接
      connection.disconnect();
    }
    return result;
  }
}

第二種方式:apache HttpClient3.1

package com.powerX.httpClient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;

public class HttpClient3 {

  public static String doGet(String url) {
    // 輸入流
    InputStream is = null;
    BufferedReader br = null;
    String result = null;
    // 創(chuàng)建httpClient實(shí)例
    HttpClient httpClient = new HttpClient();
    // 設(shè)置http連接主機(jī)服務(wù)超時(shí)時(shí)間:15000毫秒
    // 先獲取連接管理器對(duì)象,再獲取參數(shù)對(duì)象,再進(jìn)行參數(shù)的賦值
    httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
    // 創(chuàng)建一個(gè)Get方法實(shí)例對(duì)象
    GetMethod getMethod = new GetMethod(url);
    // 設(shè)置get請(qǐng)求超時(shí)為60000毫秒
    getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
    // 設(shè)置請(qǐng)求重試機(jī)制,默認(rèn)重試次數(shù):3次,參數(shù)設(shè)置為true,重試機(jī)制可用,false相反
    getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));
    try {
      // 執(zhí)行Get方法
      int statusCode = httpClient.executeMethod(getMethod);
      // 判斷返回碼
      if (statusCode != HttpStatus.SC_OK) {
        // 如果狀態(tài)碼返回的不是ok,說明失敗了,打印錯(cuò)誤信息
        System.err.println("Method faild: " + getMethod.getStatusLine());
      } else {
        // 通過getMethod實(shí)例,獲取遠(yuǎn)程的一個(gè)輸入流
        is = getMethod.getResponseBodyAsStream();
        // 包裝輸入流
        br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

        StringBuffer sbf = new StringBuffer();
        // 讀取封裝的輸入流
        String temp = null;
        while ((temp = br.readLine()) != null) {
          sbf.append(temp).append("\r\n");
        }

        result = sbf.toString();
      }

    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 關(guān)閉資源
      if (null != br) {
        try {
          br.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      if (null != is) {
        try {
          is.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      // 釋放連接
      getMethod.releaseConnection();
    }
    return result;
  }

  public static String doPost(String url, Map<String, Object> paramMap) {
    // 獲取輸入流
    InputStream is = null;
    BufferedReader br = null;
    String result = null;
    // 創(chuàng)建httpClient實(shí)例對(duì)象
    HttpClient httpClient = new HttpClient();
    // 設(shè)置httpClient連接主機(jī)服務(wù)器超時(shí)時(shí)間:15000毫秒
    httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
    // 創(chuàng)建post請(qǐng)求方法實(shí)例對(duì)象
    PostMethod postMethod = new PostMethod(url);
    // 設(shè)置post請(qǐng)求超時(shí)時(shí)間
    postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);

    NameValuePair[] nvp = null;
    // 判斷參數(shù)map集合paramMap是否為空
    if (null != paramMap && paramMap.size() > 0) {// 不為空
      // 創(chuàng)建鍵值參數(shù)對(duì)象數(shù)組,大小為參數(shù)的個(gè)數(shù)
      nvp = new NameValuePair[paramMap.size()];
      // 循環(huán)遍歷參數(shù)集合map
      Set<Entry<String, Object>> entrySet = paramMap.entrySet();
      // 獲取迭代器
      Iterator<Entry<String, Object>> iterator = entrySet.iterator();

      int index = 0;
      while (iterator.hasNext()) {
        Entry<String, Object> mapEntry = iterator.next();
        // 從mapEntry中獲取key和value創(chuàng)建鍵值對(duì)象存放到數(shù)組中
        try {
          nvp[index] = new NameValuePair(mapEntry.getKey(),
              new String(mapEntry.getValue().toString().getBytes("UTF-8"), "UTF-8"));
        } catch (UnsupportedEncodingException e) {
          e.printStackTrace();
        }
        index++;
      }
    }
    // 判斷nvp數(shù)組是否為空
    if (null != nvp && nvp.length > 0) {
      // 將參數(shù)存放到requestBody對(duì)象中
      postMethod.setRequestBody(nvp);
    }
    // 執(zhí)行POST方法
    try {
      int statusCode = httpClient.executeMethod(postMethod);
      // 判斷是否成功
      if (statusCode != HttpStatus.SC_OK) {
        System.err.println("Method faild: " + postMethod.getStatusLine());
      }
      // 獲取遠(yuǎn)程返回的數(shù)據(jù)
      is = postMethod.getResponseBodyAsStream();
      // 封裝輸入流
      br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

      StringBuffer sbf = new StringBuffer();
      String temp = null;
      while ((temp = br.readLine()) != null) {
        sbf.append(temp).append("\r\n");
      }

      result = sbf.toString();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 關(guān)閉資源
      if (null != br) {
        try {
          br.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      if (null != is) {
        try {
          is.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      // 釋放連接
      postMethod.releaseConnection();
    }
    return result;
  }
}

第三種方式:apache  httpClient4.5

package com.powerX.httpClient;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class HttpClient4 {

  public static String doGet(String url) {
    CloseableHttpClient httpClient = null;
    CloseableHttpResponse response = null;
    String result = "";
    try {
      // 通過址默認(rèn)配置創(chuàng)建一個(gè)httpClient實(shí)例
      httpClient = HttpClients.createDefault();
      // 創(chuàng)建httpGet遠(yuǎn)程連接實(shí)例
      HttpGet httpGet = new HttpGet(url);
      // 設(shè)置請(qǐng)求頭信息,鑒權(quán)
      httpGet.setHeader("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
      // 設(shè)置配置請(qǐng)求參數(shù)
      RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 連接主機(jī)服務(wù)超時(shí)時(shí)間
          .setConnectionRequestTimeout(35000)// 請(qǐng)求超時(shí)時(shí)間
          .setSocketTimeout(60000)// 數(shù)據(jù)讀取超時(shí)時(shí)間
          .build();
      // 為httpGet實(shí)例設(shè)置配置
      httpGet.setConfig(requestConfig);
      // 執(zhí)行g(shù)et請(qǐng)求得到返回對(duì)象
      response = httpClient.execute(httpGet);
      // 通過返回對(duì)象獲取返回?cái)?shù)據(jù)
      HttpEntity entity = response.getEntity();
      // 通過EntityUtils中的toString方法將結(jié)果轉(zhuǎn)換為字符串
      result = EntityUtils.toString(entity);
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 關(guān)閉資源
      if (null != response) {
        try {
          response.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      if (null != httpClient) {
        try {
          httpClient.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }
    return result;
  }

  public static String doPost(String url, Map<String, Object> paramMap) {
    CloseableHttpClient httpClient = null;
    CloseableHttpResponse httpResponse = null;
    String result = "";
    // 創(chuàng)建httpClient實(shí)例
    httpClient = HttpClients.createDefault();
    // 創(chuàng)建httpPost遠(yuǎn)程連接實(shí)例
    HttpPost httpPost = new HttpPost(url);
    // 配置請(qǐng)求參數(shù)實(shí)例
    RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 設(shè)置連接主機(jī)服務(wù)超時(shí)時(shí)間
        .setConnectionRequestTimeout(35000)// 設(shè)置連接請(qǐng)求超時(shí)時(shí)間
        .setSocketTimeout(60000)// 設(shè)置讀取數(shù)據(jù)連接超時(shí)時(shí)間
        .build();
    // 為httpPost實(shí)例設(shè)置配置
    httpPost.setConfig(requestConfig);
    // 設(shè)置請(qǐng)求頭
    httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
    // 封裝post請(qǐng)求參數(shù)
    if (null != paramMap && paramMap.size() > 0) {
      List<NameValuePair> nvps = new ArrayList<NameValuePair>();
      // 通過map集成entrySet方法獲取entity
      Set<Entry<String, Object>> entrySet = paramMap.entrySet();
      // 循環(huán)遍歷,獲取迭代器
      Iterator<Entry<String, Object>> iterator = entrySet.iterator();
      while (iterator.hasNext()) {
        Entry<String, Object> mapEntry = iterator.next();
        nvps.add(new BasicNameValuePair(mapEntry.getKey(), mapEntry.getValue().toString()));
      }

      // 為httpPost設(shè)置封裝好的請(qǐng)求參數(shù)
      try {
        httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
      }
    }
    try {
      // httpClient對(duì)象執(zhí)行post請(qǐng)求,并返回響應(yīng)參數(shù)對(duì)象
      httpResponse = httpClient.execute(httpPost);
      // 從響應(yīng)對(duì)象中獲取響應(yīng)內(nèi)容
      HttpEntity entity = httpResponse.getEntity();
      result = EntityUtils.toString(entity);
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 關(guān)閉資源
      if (null != httpResponse) {
        try {
          httpResponse.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      if (null != httpClient) {
        try {
          httpClient.close();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }
    return result;
  }
}

有時(shí)候我們?cè)谑褂胮ost請(qǐng)求時(shí),可能傳入的參數(shù)是json或者其他格式,此時(shí)我們則需要更改請(qǐng)求頭及參數(shù)的設(shè)置信息,以httpClient4.5為例,更改下面兩列配置:httpPost.setEntity(new StringEntity("你的json串"));      httpPost.addHeader("Content-Type", "application/json")。

以上所述是小編給大家介紹的java實(shí)現(xiàn)HTTP請(qǐng)求的三種方式詳解整合,希望對(duì)大家有所幫助,如果大家有任何疑問請(qǐng)給我留言,小編會(huì)及時(shí)回復(fù)大家的。在此也非常感謝大家對(duì)億速云網(wǎng)站的支持!

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