HttpURLConnection实现HttpClient工具类（get/post请求，文件上传）

一时失言乱红尘 2022-06-04 00:08 273阅读 0赞

本博客简单介绍一下HttpURLConnection实现的POST和GET请求以及文件上传，还有文件上传的服务器代码实现。

  1. import java.io.BufferedReader;
  2. import java.io.DataOutputStream;
  3. import java.io.File;
  4. import java.io.FileInputStream;
  5. import java.io.InputStream;
  6. import java.io.InputStreamReader;
  7. import java.io.OutputStream;
  8. import java.net.HttpURLConnection;
  9. import java.net.URL;
  10. import java.net.URLEncoder;
  11. import java.util.HashMap;
  12. import java.util.Map;
  14. import org.apache.http.client.HttpResponseException;
  15. import org.slf4j.Logger;
  16. import org.slf4j.LoggerFactory;
  18. public class HttpClient {
  19.     protected final static Logger logger = LoggerFactory.getLogger(HttpClient.class);
  21.     /**
  22.       * Description:文件上传，以及可以传递参数，支持文件批量上传
  23.       * 
  24.       * @param actionUrl 请求地址
  25.       * @param params  参数
  26.       * @param files  多个文件
  27.       * @return
  28.       * @throws Exception
  29.      */
  30.     public static Map<String, Object> post(String actionUrl, Map<String, String> params, Map<String, File> files)
  31.             throws Exception {
  32.         Map<String, Object> map = new HashMap<String, Object>();
  33.         logger.info("post file  url:" + actionUrl + "  params:" + params);
  34.         String BOUNDARY = java.util.UUID.randomUUID().toString();
  35.         String PREFIX = "--", LINEND = "\r\n";
  36.         String MULTIPART_FROM_DATA = "multipart/form-data";
  37.         String CHARSET = "UTF-8";
  39.         URL uri = new URL(actionUrl);
  40.         HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
  41.         conn.setReadTimeout(10 * 1000); // cache max time
  42.         conn.setConnectTimeout(5*1000);
  43.         conn.setDoInput(true);// allow input
  44.         conn.setDoOutput(true);// allow output
  45.         conn.setUseCaches(false); // cache is disable
  46.         conn.setRequestMethod("POST");
  47.         conn.setRequestProperty("connection", "keep-alive");
  48.         conn.setRequestProperty("Charsert", "UTF-8");
  49.         conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA + ";boundary=" + BOUNDARY);
  50.         // construct params for Text
  51.         StringBuilder sb = new StringBuilder();
  52.         for (Map.Entry<String, String> entry : params.entrySet()) {
  53.             sb.append(PREFIX);
  54.             sb.append(BOUNDARY);
  55.             sb.append(LINEND);
  56.             sb.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"" + LINEND);
  57.             sb.append("Content-Type: text/plain; charset=" + CHARSET + LINEND);
  58.             sb.append("Content-Transfer-Encoding: 8bit" + LINEND);
  59.             sb.append(LINEND);
  60.             sb.append(entry.getValue());
  61.             sb.append(LINEND);
  62.         }
  64.         DataOutputStream outStream = new DataOutputStream(conn.getOutputStream());
  65.         outStream.write(sb.toString().getBytes("utf-8"));
  66.         // send data
  67.         if (files != null) {
  68.             for (Map.Entry<String, File> file : files.entrySet()) {
  69.                 StringBuilder sb1 = new StringBuilder();
  70.                 sb1.append(PREFIX);
  71.                 sb1.append(BOUNDARY);
  72.                 sb1.append(LINEND);
  73.                 sb1.append("Content-Disposition: form-data; name=\"" + file.getKey() + "\"; filename=\""
  74.                         + file.getValue() + "\"" + LINEND);
  75.                 sb1.append("Content-Type: application/octet-stream; charset=" + CHARSET + LINEND);
  76.                 sb1.append(LINEND);
  77.                 outStream.write(sb1.toString().getBytes());
  79.                 InputStream is = new FileInputStream(file.getValue());
  80.                 try {
  81.                     byte[] buffer = new byte[(int) file.getValue().length()];
  82.                     int len = 0;
  83.                     while ((len = is.read(buffer)) != -1) {
  84.                         outStream.write(buffer, 0, len);
  85.                     }
  86.                 } catch (Exception e) {
  87.                     throw e;
  88.                 } finally {
  89.                     is.close();
  90.                     outStream.write(LINEND.getBytes());
  91.                 }
  93.             }
  94.         }
  96.         // the finsh flag
  97.         byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes();
  98.         outStream.write(end_data);
  99.         outStream.flush();
  101.         // get response
  102.         int res = conn.getResponseCode();
  103.         map.put("status", res);
  104.         InputStream in = null;
  105.         String result = null;
  106.         switch (res) {
  107.         case 200:
  108.             in = conn.getInputStream();
  109.             int ch;
  110.             StringBuilder sb2 = new StringBuilder();
  111.             while ((ch = in.read()) != -1) {
  112.                 sb2.append((char) ch);
  113.             }
  114.             result = sb2.toString();
  115.             map.put("returnString", result);
  116.             break;
  117.         case 403:
  118.             throw new HttpResponseException(res, "request forbided");
  119.         case 404:
  120.             throw new HttpResponseException(res, "not fonud such address");
  121.         default:
  122.             throw new Exception("undefine error:" + res);
  123.         }
  124.         conn.disconnect();
  125.         return map;
  126.     }
  128.     public static String post(String actionUrl, Map<String, String> params) throws Exception {
  129.         String contentType = "application/x-www-form-urlencoded";
  130.         URL uri = new URL(actionUrl);
  131.         HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
  132.         conn.setReadTimeout(5 * 1000); // Cache max time
  133.         conn.setConnectTimeout(5*1000);
  134.         conn.setDoInput(true);// allow input
  135.         conn.setDoOutput(true);// Allow output
  136.         conn.setUseCaches(false); // cache is disable
  137.         conn.setRequestMethod("POST");
  138.         conn.setRequestProperty("connection", "keep-alive");
  139.         conn.setRequestProperty("Charsert", "UTF-8");
  140.         conn.setRequestProperty("Content-Type", contentType);
  141.         StringBuilder sb = new StringBuilder();
  143.         for (Map.Entry<String, String> entry : params.entrySet()) {
  144.             if (sb.length() > 0) {
  145.                 sb.append("&");
  146.             }
  147.             sb.append(entry.getKey());
  148.             sb.append("=");
  149.             sb.append(URLEncoder.encode(entry.getValue()));
  150.         }
  151.         OutputStream output = conn.getOutputStream();
  152.         output.write(sb.toString().getBytes());
  153.         output.flush();
  155.         int res = conn.getResponseCode();
  156.         InputStream in = null;
  157.         String result = null;
  158.         switch (res) {
  159.             case 200:
  160.                 in = conn.getInputStream();
  161.                 String line;
  162.                 StringBuilder sb2 = new StringBuilder();
  163.                 BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(in,"UTF-8")); 
  164.                 while ((line = bufferedReader.readLine()) != null) {  
  165.                     sb2.append(line);  
  166.                 }  
  167.                 result = sb2.toString();
  168.                 break;
  169.             case 403:
  170.                 throw new HttpResponseException(res, "request forbided");
  171.             case 404:
  172.                 throw new HttpResponseException(res, "not fonud such address");
  173.             default:
  174.                 throw new Exception("undefine error:" + res);
  175.         }
  176.         return result;
  177.     }
  179.     public static String get(String actionUrl, Map<String, String> params) throws Exception {
  180.         String contentType = "application/x-www-form-urlencoded";
  182.         StringBuilder sb = new StringBuilder();
  183.         for (Map.Entry<String, String> entry : params.entrySet()) {
  184.             if (sb.length() > 0) {
  185.                 sb.append("&");
  186.             }
  187.             sb.append(entry.getKey());
  188.             sb.append("=");
  189.             sb.append(URLEncoder.encode(entry.getValue()));
  190.         }
  191.         if (actionUrl.endsWith("?")) {
  192.             actionUrl += sb.toString();
  193.         } else {
  194.             actionUrl += "?" + sb.toString();
  195.         }
  196.         URL uri = new URL(actionUrl);
  197.         HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
  198.         conn.setReadTimeout(5 * 1000); // Cache max time
  199.         conn.setDoInput(true);// allow input
  200.         conn.setDoOutput(true);// Allow output
  201.         conn.setUseCaches(false); // cache is disable
  202.         conn.setRequestMethod("GET");
  203.         conn.setRequestProperty("connection", "keep-alive");
  204.         conn.setRequestProperty("Charsert", "UTF-8");
  205.         conn.setRequestProperty("Content-Type", contentType);
  207.         int res = conn.getResponseCode();
  208.         // Log.i("le_assistant","actionUrl:" +actionUrl+"  ResponseCode:"+res);
  209.         InputStream in = null;
  210.         String result = null;
  211.         switch (res) {
  212.         case 200:
  213.             in = conn.getInputStream();
  214.             String line;
  215.             StringBuilder sb2 = new StringBuilder();
  216.             BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(in,"UTF-8")); 
  217.             while ((line = bufferedReader.readLine()) != null) {  
  218.                 sb2.append(line);  
  219.             }
  220.             result = sb2.toString();
  221.             break;
  222.         case 403:
  223.             throw new HttpResponseException(res, "request forbided");
  224.         case 404:
  225.             throw new HttpResponseException(res, "not fonud such address");
  226.         default:
  227.             throw new Exception("undefine error:" + res);
  228.         }
  229.         return result;
  230.     }
  232.     public static void main(String[] args) {
  233.         String url = "http://localhost:8990/file/Upload";
  234.         Map<String,String> params = new HashMap<String, String>();
  235.         Map<String, File> files = new HashMap<String, File>();
  236.         File file = new File("d:\\a.png");
  237.         files.put("file", file);
  239.         try {
  240.             System.out.println(post(url, params,files));
  241.         } catch (Exception e) {
  242.             e.printStackTrace();
  243.         }
  244.     }
  247. }

文件上传的服务器代码实现(Java)：

  1. @RestController
  2. @RequestMapping("/file")
  3. public class FileUploadController {
  5.     /**
  6.      * 图片上传
  7.      * @param file
  8.      * @return
  9.      */
  10.     @RequestMapping("/upload")
  11.     @ResponseBody
  12.     public Object fileUpload(@RequestParam(value = "file", required = false) MultipartFile file){
  13.         JSONObject object = new JSONObject();
  14.         try {
  15.             if(file!=null){
  16.                 //保存文件
  17.                 String fileName = file.getOriginalFilename();
  18.                 String fileExt = getExtention(fileName);
  19.                 byte[] fileByte = file.getBytes();
  20.                 //文件处理
  22.             }
  23.         } catch (IOException e) {
  24.             e.printStackTrace();
  25.         }
  26.         return object;
  27.     }
  29. }

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