转载地址:
http://blog.csdn.net/hbcui1984/archive/2008/07/27/2720204.aspx
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
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public
static
boolean
uploadFile(String url,
int
port,String username, String password, String path, String filename, InputStream input) {
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boolean
success =
false
;
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FTPClient ftp =
new
FTPClient();
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try
{
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int
reply;
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ftp.connect(url, port);
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ftp.login(username, password);
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reply = ftp.getReplyCode();
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if
(!FTPReply.isPositiveCompletion(reply)) {
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ftp.disconnect();
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return
success;
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}
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ftp.changeWorkingDirectory(path);
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ftp.storeFile(filename, input);
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input.close();
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ftp.logout();
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success =
true
;
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}
catch
(IOException e) {
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e.printStackTrace();
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}
finally
{
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if
(ftp.isConnected()) {
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try
{
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ftp.disconnect();
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}
catch
(IOException ioe) {
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}
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}
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}
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return
success;
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}
/**
* Description: 向FTP服务器上传文件
* @Version1.0 Jul 27, 2008 4:31:09 PM by 崔红保(cuihongbao@d-heaven.com)创建
* @param url FTP服务器hostname
* @param port FTP服务器端口
* @param username FTP登录账号
* @param password FTP登录密码
* @param path FTP服务器保存目录
* @param filename 上传到FTP服务器上的文件名
* @param input 输入流
* @return 成功返回true,否则返回false
*/
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);//连接FTP服务器
//如果采用默认端口,可以使用ftp.connect(url)的方式直接连接FTP服务器
ftp.login(username, password);//登录
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;
}
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:
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@Test
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public
void
testUpLoadFromDisk(){
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try
{
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FileInputStream in=
new
FileInputStream(
new
File(
"D:/test.txt"
));
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boolean
flag = uploadFile(
"127.0.0.1"
,
21
,
"test"
,
"test"
,
"D:/ftp"
,
"test.txt"
, in);
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System.out.println(flag);
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}
catch
(FileNotFoundException e) {
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e.printStackTrace();
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}
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}
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
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@Test
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public
void
testUpLoadFromString(){
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try
{
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InputStream input =
new
ByteArrayInputStream(
"test ftp"
.getBytes(
"utf-8"
));
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boolean
flag = uploadFile(
"127.0.0.1"
,
21
,
"test"
,
"test"
,
"D:/ftp"
,
"test.txt"
, input);
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System.out.println(flag);
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}
catch
(UnsupportedEncodingException e) {
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e.printStackTrace();
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}
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}
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:
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public
static
boolean
downFile(String url,
int
port,String username, String password, String remotePath,String fileName,String localPath) {
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boolean
success =
false
;
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FTPClient ftp =
new
FTPClient();
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try
{
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int
reply;
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ftp.connect(url, port);
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ftp.login(username, password);
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reply = ftp.getReplyCode();
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if
(!FTPReply.isPositiveCompletion(reply)) {
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ftp.disconnect();
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return
success;
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}
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ftp.changeWorkingDirectory(remotePath);
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FTPFile[] fs = ftp.listFiles();
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for
(FTPFile ff:fs){
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if
(ff.getName().equals(fileName)){
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File localFile =
new
File(localPath+
"/"
+ff.getName());
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OutputStream is =
new
FileOutputStream(localFile);
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ftp.retrieveFile(ff.getName(), is);
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is.close();
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}
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}
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ftp.logout();
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success =
true
;
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}
catch
(IOException e) {
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e.printStackTrace();
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}
finally
{
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if
(ftp.isConnected()) {
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try
{
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ftp.disconnect();
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}
catch
(IOException ioe) {
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}
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}
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}
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return
success;
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}