一、下載客戶端代碼
package javadownload; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; /** * @說明導出虛擬機* @author wxt * @version 1.0 * @since */ public class GetVM { /** * 測試* @param args */ public static void main(String[] args) { String url = "http://192.168.5.102:8845/xx"; byte[] btImg = getVMFromNetByUrl(url); if(null != btImg && btImg.length > 0){ System.out.println("讀取到：" + btImg.length + " 字節"); String fileName = "ygserver"; writeImageToDisk(btImg, fileName); }else{ System.out.println("沒有從該連接獲得內容"); } } /** * 將vm 寫入到磁盤* @param vm 數據流* @param fileName 文件保存時的名稱*/ public static void writeImageToDisk(byte[] vm, String fileName){ try { File file = new File("./" + fileName); FileOutputStream fops = new FileOutputStream(file); fops.write(vm); fops.flush(); fops.close(); System.out.println("下載完成"); } catch (Exception e) { e.printStackTrace(); } } /** * 根據地址獲得數據的字節流* @param strUrl 網絡連接地址* @return */ public static byte[] getVMFromNetByUrl(String strUrl){ try { URL url = new URL(strUrl); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5 * 1000); InputStream inStream = conn.getInputStream();//通過輸入流獲取數據byte[] btImg = readInputStream(inStream);//得到的二進制數據return btImg; } catch (Exception e) { e.printStackTrace(); } return null; } /** * 從輸入流中獲取數據* @param inStream 輸入流* @return * @throws Exception */ public static byte[] readInputStream(InputStream inStream) throws Exception{ ByteArrayOutputStream outStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while( (len=inStream.read(buffer)) != -1 ){ outStream.write(buffer, 0, len); } inStream.close(); return outStream.toByteArray(); } }上述代碼只適合下載小文件，如果下載大文件則會出現Exception in thread "main" java.lang.OutOfMemoryError: Java heap space 錯誤，所以如果下載大文件需要對上述代碼進行改造，代碼如下：
package javadownload; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; /** * @說明導出虛擬機* @author wxt * @version 1.0 * @since */ public class GetBigFile { /** * 測試* @param args */ public static void main(String[] args) { String url = "http://192.168.5.76:8080/export?uuid=123"; String fileName="yserver"; getVMFromNetByUrl(url,fileName); } /** * 根據地址獲下載文件* @param strUrl 網絡連接地址* @param fileName 下載文件的存儲名稱*/ public static void getVMFromNetByUrl(String strUrl,String fileName){ try { URL url = new URL(strUrl); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5 * 1000); InputStream inStream = conn.getInputStream();//通過輸入流獲取數據byte[] buffer = new byte[4096]; int len = 0; File file = new File("./" + fileName); FileOutputStream fops = new FileOutputStream(file); while( (len=inStream.read(buffer)) != -1 ){ fops.write(buffer, 0, len); } fops.flush(); fops.close(); } catch (Exception e) { e.printStackTrace(); } } }二、上傳文件客戶端：
package javadownload; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; public class FileUpload { /** * 發送請求* * @param url * 請求地址* @param filePath * 文件在服務器保存路徑（這裡是為了自己測試方便而寫，可以將該參數去掉） * @return * @throws IOException */ public int send(String url, String filePath) throws IOException { File file = new File(filePath); if (!file.exists() || !file.isFile()) { return -1; } /** * 第一部分*/ URL urlObj = new URL(url); HttpURLConnection con = (HttpURLConnection) urlObj.openConnection(); /** * 設置關鍵值*/ con.setRequestMethod("POST"); // 以Post方式提交表單，默認get方式con.setDoInput(true); con.setDoOutput(true); con.setUseCaches(false); // post方式不能使用緩存// 設置請求頭信息con.setRequestProperty("Connection", "close");//Keep-Alive con.setRequestProperty("Charset", "UTF-8"); // 設置邊界String BOUNDARY = "----------" + System.currentTimeMillis(); con.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY); // 請求正文信息// 第一部分： StringBuilder sb = new StringBuilder(); sb.append("--"); // ////////必須多兩道線sb.append(BOUNDARY); sb.append("/r/n"); sb.append("Content-Disposition: form-data;name=/"file_name/";filename=/"" + file.getName() + "/"/r/n"); sb.append("Content-Type:application/octet-stream/r/n/r/n"); sb.append("Connection:close/r/n/r/n"); byte[] head = sb.toString().getBytes("utf-8"); // 獲得輸出流OutputStream out = new DataOutputStream(con.getOutputStream()); out.write(head); // 文件正文部分DataInputStream in = new DataInputStream(new FileInputStream(file)); int bytes = 0; byte[] bufferOut = new byte[1024]; while ((bytes = in.read(bufferOut)) != -1) { out.write(bufferOut, 0, bytes); } in.close(); // 結尾部分byte[] foot = ("/r/n--" + BOUNDARY + "--/r/n").getBytes("utf-8");// 定義最後數據分隔線out.write(foot); out.flush(); out.close(); /** * 讀取服務器響應，必須讀取,否則提交不成功*/ return con.getResponseCode(); /** * 下面的方式讀取也是可以的*/ // try { // // 定義BufferedReader輸入流來讀取URL的響應// BufferedReader reader = new BufferedReader(new InputStreamReader( // con.getInputStream())); // String line = null; // while ((line = reader.readLine()) != null) { // System.out.println(line); // } // } catch (Exception e) { // System.out.println("發送POST請求出現異常！" + e); // e.printStackTrace(); // } } public static void main(String[] args) throws IOException { FileUpload up = new FileUpload(); System.out.println(up.send("http://192.168.5.102:8845/xx", "./vif.xml")); ; } }總結
以上所述是小編給大家介紹的Java下http下載文件客戶端和上傳文件客戶端實例代碼，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對武林網網站的支持！