一、下载所需要的jar包
http://commons.apache.org/net/download_net.cgi
二、编码实现
这里没有用到filter，如果用filter就可以过滤想要的文件。
public class Ftp {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Ftp ftp = new Ftp();
String hostname = "www.strawberry.com";
Integer port = 21;
String username = "username";
String password = "password";
String remote = "/c.txt";
String local = "/home/tin/LeonChen/FTP/";
try {
ftp.connect(hostname, port, username, password);
System.out.println("接收状态："+ftp.download(remote, local));
ftp.disconnect();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private FTPClient ftpClient = new FTPClient();
/*
* * 连接到FTP服务器
* * @param hostname 主机名
* * @param port 端口
* * @param username 用户名
* * @param password 密码
* * @return 是否连接成功
* * @throws IOException
*/
private boolean connect(String hostname, int port, String username,
String password) throws IOException {
ftpClient.connect(hostname, port);
ftpClient.setControlEncoding("UTF-8");
if (FTPReply.isPositiveCompletion(ftpClient.getReplyCode())) {
if (ftpClient.login(username, password)) {
return true;
}
}
disconnect();
return false;
}
/*
* 从FTP服务器上下载文件,支持断点续传，上传百分比汇报
*
* @param remote 远程文件路径
*
* @param local 本地文件路径
*
* @return 上传的状态
*
* @throws IOException
*/
public DownloadStatus download(String remote, String local)
throws IOException {
// 设置被动模式
ftpClient.enterLocalPassiveMode();
// 设置以二进制方式传输
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
DownloadStatus result;
// 检查远程文件是否存在
FTPFile[] files = ftpClient.listFiles(new String(remote
.getBytes("UTF-8"), "iso-8859-1"));
if (files.length != 1) {
System.out.println("远程文件不存在");
return DownloadStatus.Remote_File_Noexist;
}
long lRemoteSize = files[0].getSize();
String fildName = files[0].getName();
// 本地存在文件，进行断点下载
File f = new File(local+fildName);
if (f.exists()) {
long localSize = f.length();
if (localSize >= lRemoteSize) {
System.out.println("本地文件大于远程文件，下载中止");
return DownloadStatus.Local_Bigger_Remote;
}
// 进行断点续传，并记录状态
FileOutputStream out = new FileOutputStream(f, true);
ftpClient.setRestartOffset(localSize);
InputStream in = ftpClient.retrieveFileStream(new String(remote.getBytes("UTF-8"), "iso-8859-1"));
byte[] bytes = new byte[1024];
long step = lRemoteSize / 100;
long process = localSize / step;
int c;
while ((c = in.read(bytes)) != -1) {
out.write(bytes, 0, c);
localSize += c;
long nowProcess = localSize / step;
if (nowProcess > process) {
process = nowProcess;
if (process % 10 == 0)
System.out.println("下载进度：" + process);
// TODO 更新文件下载进度,值存放在process变量中
}
}
in.close();
out.close();
boolean isDo = ftpClient.completePendingCommand();
if (isDo) {
result = DownloadStatus.Download_From_Break_Success;
} else {
result = DownloadStatus.Download_From_Break_Failed;
}
} else {
OutputStream out = new FileOutputStream(f);
InputStream in = ftpClient.retrieveFileStream(new String(remote.getBytes("UTF-8"), "iso-8859-1"));
byte[] bytes = new byte[1024];
long step = lRemoteSize / 100;
long process = 0;
long localSize = 0L;
int c;
while ((c = in.read(bytes)) != -1) {
out.write(bytes, 0, c);
localSize += c;
long nowProcess = localSize / step;
if (nowProcess > process) {
process = nowProcess;
if (process % 10 == 0)
System.out.println("下载进度：" + process);
// TODO 更新文件下载进度,值存放在process变量中
}
}
in.close();
out.close();
boolean upNewStatus = ftpClient.completePendingCommand();
if (upNewStatus) {
result = DownloadStatus.Download_New_Success;
} else {
result = DownloadStatus.Download_New_Failed;
}
}
return result;
}
private void disconnect() throws IOException {
if (ftpClient.isConnected()) {
ftpClient.disconnect();
}
}
}