JavaFTP下载文件和文件夹

导入apache-net-2.0.jar到工程中以及其他jar

import java.io.File;

import java.io.FileOutputStream;
import java.io.IOException;
import java.net.SocketException;


import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;
import org.apache.log4j.Logger;


/**
 * 采用的是apache commons-net架包中的ftp工具类实现的
 * 
 * @author chiyong
 * 
 */
public class FtpCollectionUtil {
private String username;
private String password;
private String ftpHostName;
private int port = 21;
private FTPClient ftpClient = new FTPClient();
private FileOutputStream fos = null;
private Logger logger = Logger.getLogger(FtpCollectionUtil.class);


public FtpCollectionUtil(String username, String password,
String ftpHostName, int port) {
super();
this.username = username;
this.password = password;
this.ftpHostName = ftpHostName;
this.port = port;
}


/**
* 建立连接b
*/
private void connect() {
try {
logger.debug("开始连接");
// 连接
ftpClient.connect(ftpHostName, port);
int reply = ftpClient.getReplyCode();
if (!FTPReply.isPositiveCompletion(reply)) {
ftpClient.disconnect();
}
// 登录
ftpClient.login(username, password);
ftpClient.setBufferSize(256);


ftpClient.setFileType(FTP.BINARY_FILE_TYPE);


ftpClient.setControlEncoding("utf8");
logger.debug("登录成功！");
logger.debug("开始登录！");
} catch (SocketException e) {
logger.error("", e);
} catch (IOException e) {
logger.error("", e);
}


}
/**
* 关闭输入输出流
* 
* @param fos
*/
private void close(FileOutputStream fos) {
try {
if (fos != null) {
fos.close();
}

ftpClient.logout();
logger.info("退出登录");
ftpClient.disconnect();
logger.info("关闭连接");
} catch (IOException e) {
logger.error("", e);
}
}


/**
* 下载文件
* 
* @param ftpFileName
* @param localDir
*/
public void down(String ftpFileName, String localDir) {
connect();
downFileOrDir(ftpFileName, localDir);
close(fos);
}


private void downFileOrDir(String ftpFileName, String localDir) {
try {
File file = new File(ftpFileName);


File temp = new File(localDir);


if (!temp.exists()) {
temp.mkdirs();
}
// 判断是否是目录
if (isDir(ftpFileName)) {
String[] names = ftpClient.listNames();
for (int i = 0; i < names.length; i++) {
System.out.println(names[i] + "^^^^^^^^^^^^^^");
if (isDir(names[i])) {
downFileOrDir(ftpFileName + '/' + names[i], localDir
+ File.separator + names[i]);
ftpClient.changeToParentDirectory();
} else {
File localfile = new File(localDir + File.separator
+ names[i]);
if (!localfile.exists()) {
fos = new FileOutputStream(localfile);
ftpClient.retrieveFile(names[i], fos);


} else {
logger.debug("开始删除文件");
file.delete();
logger.debug("文件已经删除");
fos = new FileOutputStream(localfile);
ftpClient.retrieveFile(ftpFileName, fos);


}


}
}
} else {


File localfile = new File(localDir + File.separator
+ file.getName());
if (!localfile.exists()) {
fos = new FileOutputStream(localfile);
ftpClient.retrieveFile(ftpFileName, fos);


} else {
logger.debug("开始删除文件");
file.delete();
logger.debug("文件已经删除");
fos = new FileOutputStream(localfile);
ftpClient.retrieveFile(ftpFileName, fos);


}
ftpClient.changeToParentDirectory();


}


logger.info("下载成功！");
} catch (SocketException e) {
logger.error("连接失败！", e);
} catch (IOException e) {
logger.error("下载失败！", e);
}


}


// 判断是否是目录
public boolean isDir(String fileName) {
try {
// 切换目录，若当前是目录则返回true,否则返回true。
boolean falg = ftpClient.changeWorkingDirectory(fileName);
return falg;
} catch (Exception e) {
e.printStackTrace();
logger.error("", e);
}

return false;
}

public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}

public String getFtpHostName() {
return ftpHostName;
}
public void setFtpHostName(String ftpHostName) {
this.ftpHostName = ftpHostName;
}


public int getPort() {
return port;
}
public void setPort(int port) {
this.port = port;
}
public class TestFileUtil {


public static void main(String[] args) {
/**
* apache common-net实现的
*/
FtpCollectionUtil ftpUtil = new FtpCollectionUtil("webfocus1",
"webfocus1", "192.168.0.2", 21);

// /home/webfocus1/apache-tomcat-6.0.37/webapps/NEZA_ROOT/要下载的文件夹。
ftpUtil.down(
"/home/webfocus1/apache-tomcat-6.0.37/webapps/NEZA_ROOT/",
"D://a");



}
}

}