【IT168技术文档】

     要在项目里实现用ftp下载文件. 遇到了很多问题. 于是我推荐他用Jakarta-Commons项目中的net组件在实现. 其实之前我也没有实际用过, 稍稍看了一下文档,知道里面有个ftp包能完成相关的操作. 于是我的同事就兴致勃勃的拿去用了. 可用了以后才发现有很多问题, 搞得焦头烂额. 经过我们的努力, 终于把问题都解决了, 下面我把遇到的问题和解决方案写下来, 以备其他想要用common-net包的朋友参考.

首先把代码贴出来:

public class ClientTest {
2     public static void main(String[] args) {
3         String url = "172.17.1.38";
4         String user = "test";
5         String pwd = "test";
6
7         FTPClient ftp = new FTPClient();
8         ftp.setControlEncoding("GBK");
9         FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_NT);
10         conf.setServerLanguageCode("zh");
11         ftp.configure(conf);
12
13         try {
14             ftp.connect(url);
15             if (ftp.login(user, pwd)) {
16                 int reply = ftp.getReplyCode();
17                 if (!FTPReply.isPositiveCompletion(reply)) {
18                     ftp.disconnect();
19                     System.out.println("disconnect");
20                 } else {
21                     ftp.enterLocalPassiveMode();
22                     ftp.setFileType(FTP.BINARY_FILE_TYPE);
23
24                     File dir = new File("down");
25                     if (!dir.exists()) {
26                         dir.mkdirs();
27                     }
28
29                     String[] names = ftp.listNames();
30                     for (String name : names) {
31                         File file = new File(dir.getPath() + File.separator + name);
32                         if (!file.exists()) {
33                             file.createNewFile();
34                         }
35                         long pos = file.length();
36                         RandomAccessFile raf = new RandomAccessFile(file, "rw");
37                         raf.seek(pos);
38                         ftp.setRestartOffset(pos);
39
40                         InputStream is = ftp.retrieveFileStream(name);
41                         if (is == null) {
42                             System.out.println("no such file:" + name);
43                         } else {
44                             System.out.println("start getting file:" + name);
45
46                             int b;
47                             while ((b = is.read()) != -1) {
48                                 raf.write(b);
49                             }
50                             if (ftp.getReply() == FTPReply.CODE_226) {
51                                 System.out.println("done!");
52                             }
53                             is.close();
54                         }
55                         raf.close();
56                     }
57                 }
58                 ftp.logout();
59             }
60         } catch (IOException e) {
61             e.printStackTrace();
62         }
63     }
64 }