文件下载添加断点续传功能

src/main/java/com/founder/util/FtpUtil.java

@@ -126,14 +126,59 @@ public class FtpUtil {
 			}
 			ftp.changeWorkingDirectory(remotePath);// 转移到FTP服务器目录
 			ftp.enterLocalPassiveMode();
+			ftp.setFileType(FTP.BINARY_FILE_TYPE);
 			FTPFile[] fs = ftp.listFiles();
 			for (FTPFile ff : fs) {
-				if (ff.getName().equals(fileName)) {
-					File localFile = new File(localPath + "/" + ff.getName());
+				String remotefileName = ff.getName();
+				if (remotefileName.equals(fileName)) {
+					File localFile = new File(localPath +"/" + remotefileName);
+					long remotesize = ff.getSize();
+					// 本地存在文件，进行断点下载
+					if(localFile.exists()){
+						System.out.println("文件已存在");
+						long localsize = localFile.length();
+						if(localsize>=remotesize){
+							//文件已下载完毕
+							System.out.println("文件已存在，无需下载");
+							continue;
+						}
+						// 进行断点续传，并记录状态
+						// 找出本地已经接收了多少
+						ftp.setRestartOffset(localsize);
+						FileOutputStream fos = null;
+						try {
+							System.out.println(localPath);
+							System.out.println(localFile.getName());
+							System.out.println(localFile.getAbsolutePath());
+
+							localFile.createNewFile();
+							fos = new FileOutputStream(localFile,true);
+							System.out.println("断点续传下载中：" + fileName);
+							ftp.retrieveFile(fileName, fos);
+							fos.close();
+						} catch (Exception e) {
+							e.printStackTrace();
+						} finally {
+						}
+					}else{
+						OutputStream fos = null;
+						try {
+							System.out.println(localPath);
+							System.out.println(localFile.getName());
+							System.out.println(localFile.getAbsolutePath());
+
+							localFile.createNewFile();
+							fos = new FileOutputStream(localFile);
+							System.out.println("下载中：" + fileName);
+							ftp.retrieveFile(fileName, fos);
+							fos.close();
+						} catch (Exception e) {
+							e.printStackTrace();
+						} finally {
+						}
+
+					}
 
-					OutputStream is = new FileOutputStream(localFile);
-					ftp.retrieveFile(ff.getName(), is);
-					is.close();
 				}
 			}
 
@@ -146,6 +191,7 @@ public class FtpUtil {
 				try {
 					ftp.disconnect();
 				} catch (IOException ioe) {
+					ioe.printStackTrace();
 				}
 			}
 		}
@@ -155,7 +201,6 @@ public class FtpUtil {
 
 	public  static boolean uploadFtp(InputStream in,String wjmc) {
 
-
 		//上传文件到ftp文件服务器begin20180806
 	/*	String  ip = ftpConfig.getServerip();
 		int  port =  Integer.parseInt(ftpConfig.getPortid());
@@ -172,12 +217,13 @@ public class FtpUtil {
 
 	public static void main(String[] args) {
 		try {
-	        FileInputStream in=new FileInputStream(new File("D:\\JCCJ-R1100000500002014070001.xml"));
+	       // FileInputStream in=new FileInputStream(new File("D:\\JCCJ-R1100000500002014070001.xml"));
 	      //  boolean flag = uploadFile("47.92.129.99", 4546, "ftpuser", "fou3rfnder4SD1", "/home/ftpuser/","/2016/", "JCCJ-两岸三地R1100000500002014070001.xml", in);
-			boolean flag = downloadFile("47.92.129.99", 4546, "ftpuser", "fou3rfnder4SD1", "2016/", "appone.zip","D:\\");
+			boolean flag = downloadFile("47.92.129.99", 4546, "ftpuser", "fou3rfnder4SD1", "2016/", "appone.zip","C:/tmp");
 	        System.out.println(flag);
-	    } catch (FileNotFoundException e) {
+	    } catch (Exception e) {
 	        e.printStackTrace();
 	    }
 	}
+
 }