本文介紹了JAVA通過HttpURLConnection 上傳和下載文件的方法，分享給大家，具體如下：
HttpURLConnection文件上傳
HttpURLConnection采用模擬瀏覽器上傳的數據格式，上傳給服務器
上傳代碼如下：
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package com.util;import java.io.BufferedInputStream;import java.io.BufferedReader;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.net.URLConnection;import java.util.Iterator;import java.util.Map;/** * Java原生的API可用于發送HTTP請求，即java.net.URL、java.net.URLConnection，這些API很好用、很常用， * 但不夠簡便； * * 1.通過統一資源定位器（java.net.URL）獲取連接器（java.net.URLConnection） 2.設置請求的參數 3.發送請求 * 4.以輸入流的形式獲取返回內容 5.關閉輸入流 * * @author H__D * */public class HttpConnectionUtil { /** * 多文件上傳的方法 * * @param actionUrl：上傳的路徑 * @param uploadFilePaths：需要上傳的文件路徑，數組 * @return */ @SuppressWarnings("finally") public static String uploadFile(String actionUrl, String[] uploadFilePaths) { String end = "\r\n"; String twoHyphens = "--"; String boundary = "*****"; DataOutputStream ds = null; InputStream inputStream = null; InputStreamReader inputStreamReader = null; BufferedReader reader = null; StringBuffer resultBuffer = new StringBuffer(); String tempLine = null; try { // 統一資源 URL url = new URL(actionUrl); // 連接類的父類，抽象類 URLConnection urlConnection = url.openConnection(); // http的連接類 HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection; // 設置是否從httpUrlConnection讀入，默認情況下是true; httpURLConnection.setDoInput(true); // 設置是否向httpUrlConnection輸出 httpURLConnection.setDoOutput(true); // Post 請求不能使用緩存 httpURLConnection.setUseCaches(false); // 設定請求的方法，默認是GET httpURLConnection.setRequestMethod("POST"); // 設置字符編碼連接參數 httpURLConnection.setRequestProperty("Connection", "Keep-Alive"); // 設置字符編碼 httpURLConnection.setRequestProperty("Charset", "UTF-8"); // 設置請求內容類型 httpURLConnection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary); // 設置DataOutputStream ds = new DataOutputStream(httpURLConnection.getOutputStream()); for (int i = 0; i < uploadFilePaths.length; i++) { String uploadFile = uploadFilePaths[i]; String filename = uploadFile.substring(uploadFile.lastIndexOf("//") + 1); ds.writeBytes(twoHyphens + boundary + end); ds.writeBytes("Content-Disposition: form-data; " + "name=\"file" + i + "\";filename=\"" + filename + "\"" + end); ds.writeBytes(end); FileInputStream fStream = new FileInputStream(uploadFile); int bufferSize = 1024; byte[] buffer = new byte[bufferSize]; int length = -1; while ((length = fStream.read(buffer)) != -1) { ds.write(buffer, 0, length); } ds.writeBytes(end); /* close streams */ fStream.close(); } ds.writeBytes(twoHyphens + boundary + twoHyphens + end); /* close streams */ ds.flush(); if (httpURLConnection.getResponseCode() >= 300) { throw new Exception( "HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode()); } if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK) { inputStream = httpURLConnection.getInputStream(); inputStreamReader = new InputStreamReader(inputStream); reader = new BufferedReader(inputStreamReader); tempLine = null; resultBuffer = new StringBuffer(); while ((tempLine = reader.readLine()) != null) { resultBuffer.append(tempLine); resultBuffer.append("\n"); } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { if (ds != null) { try { ds.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (reader != null) { try { reader.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (inputStreamReader != null) { try { inputStreamReader.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return resultBuffer.toString(); } } public static void main(String[] args) { // 上傳文件測試 String str = uploadFile("http://127.0.0.1:8080/image/image.do",new String[] { "/Users//H__D/Desktop//1.png","//Users/H__D/Desktop/2.png" }); System.out.println(str); }} |
HttpURLConnection文件下載
下載代碼如下：
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package com.util;import java.io.BufferedInputStream;import java.io.BufferedReader;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.net.URLConnection;import java.util.Iterator;import java.util.Map;/** * Java原生的API可用于發送HTTP請求，即java.net.URL、java.net.URLConnection，這些API很好用、很常用， * 但不夠簡便； * * 1.通過統一資源定位器（java.net.URL）獲取連接器（java.net.URLConnection） 2.設置請求的參數 3.發送請求 * 4.以輸入流的形式獲取返回內容 5.關閉輸入流 * * @author H__D * */public class HttpConnectionUtil { /** * * @param urlPath * 下載路徑 * @param downloadDir * 下載存放目錄 * @return 返回下載文件 */ public static File downloadFile(String urlPath, String downloadDir) { File file = null; try { // 統一資源 URL url = new URL(urlPath); // 連接類的父類，抽象類 URLConnection urlConnection = url.openConnection(); // http的連接類 HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection; // 設定請求的方法，默認是GET httpURLConnection.setRequestMethod("POST"); // 設置字符編碼 httpURLConnection.setRequestProperty("Charset", "UTF-8"); // 打開到此 URL 引用的資源的通信鏈接（如果尚未建立這樣的連接）。 httpURLConnection.connect(); // 文件大小 int fileLength = httpURLConnection.getContentLength(); // 文件名 String filePathUrl = httpURLConnection.getURL().getFile(); String fileFullName = filePathUrl.substring(filePathUrl.lastIndexOf(File.separatorChar) + 1); System.out.println("file length---->" + fileLength); URLConnection con = url.openConnection(); BufferedInputStream bin = new BufferedInputStream(httpURLConnection.getInputStream()); String path = downloadDir + File.separatorChar + fileFullName; file = new File(path); if (!file.getParentFile().exists()) { file.getParentFile().mkdirs(); } OutputStream out = new FileOutputStream(file); int size = 0; int len = 0; byte[] buf = new byte[1024]; while ((size = bin.read(buf)) != -1) { len += size; out.write(buf, 0, size); // 打印下載百分比 // System.out.println("下載了-------> " + len * 100 / fileLength + // "%\n"); } bin.close(); out.close(); } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { return file; } } public static void main(String[] args) { // 下載文件測試 downloadFile("http://localhost:8080/images/1467523487190.png", "/Users/H__D/Desktop"); }} |
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持服務器之家。
原文鏈接：http://www.cnblogs.com/h--d/p/5638092.html
