在JAVA程序中,经常需要和FTP打交道,比如向FTP服务器上传文件、下载文件,本文简单介绍如何利用jakarta commons中的FTPClient(在commons-net包中)实现上传下载文件。
一、上传文件
原理就不介绍了,大家直接看代码吧
- public static boolean uploadFile(String url,int port,String username, String password, String path, String filename, InputStream input) {
- boolean success = false;
- FTPClient ftp = new FTPClient();
- try {
- int reply;
- ftp.connect(url, port);
-
- ftp.login(username, password);
- reply = ftp.getReplyCode();
- if (!FTPReply.isPositiveCompletion(reply)) {
- ftp.disconnect();
- return success;
- }
- ftp.changeWorkingDirectory(path);
- ftp.storeFile(filename, input);
-
- input.close();
- ftp.logout();
- success = true;
- } catch (IOException e) {
- e.printStackTrace();
- } finally {
- if (ftp.isConnected()) {
- try {
- ftp.disconnect();
- } catch (IOException ioe) {
- }
- }
- }
- return success;
- }<pre></pre>
下面我们写两个小例子:
1.将本地文件上传到FTP服务器上,代码如下:
- @Test
- public void testUpLoadFromDisk(){
- try {
- FileInputStream in=new FileInputStream(new File("D:/test.txt"));
- boolean flag = uploadFile("127.0.0.1", 21, "test", "test", "D:/ftp", "test.txt", in);
- System.out.println(flag);
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- }
- }<pre></pre>
2.在FTP服务器上生成一个文件,并将一个字符串写入到该文件中
- @Test
- public void testUpLoadFromString(){
- try {
- InputStream input = new ByteArrayInputStream("test ftp".getBytes("utf-8"));
- boolean flag = uploadFile("127.0.0.1", 21, "test", "test", "D:/ftp", "test.txt", input);
- System.out.println(flag);
- } catch (UnsupportedEncodingException e) {
- e.printStackTrace();
- }
- }<pre></pre>
二、下载文件
从FTP服务器下载文件的代码也很简单,参考如下:
- public static boolean downFile(String url, int port,String username, String password, String remotePath,String fileName,String localPath) {
- boolean success = false;
- FTPClient ftp = new FTPClient();
- try {
- int reply;
- ftp.connect(url, port);
-
- ftp.login(username, password);
- reply = ftp.getReplyCode();
- if (!FTPReply.isPositiveCompletion(reply)) {
- ftp.disconnect();
- return success;
- }
- ftp.changeWorkingDirectory(remotePath);
- FTPFile[] fs = ftp.listFiles();
- for(FTPFile ff:fs){
- if(ff.getName().equals(fileName)){
- File localFile = new File(localPath+"/"+ff.getName());
-
- OutputStream is = new FileOutputStream(localFile);
- ftp.retrieveFile(ff.getName(), is);
- is.close();
- }
- }
-
- ftp.logout();
- success = true;
- } catch (IOException e) {
- e.printStackTrace();
- } finally {
- if (ftp.isConnected()) {
- try {
- ftp.disconnect();
- } catch (IOException ioe) {
- }
- }
- }
- return success;
- }<pre></pre>