Java读取FTP上的txt文件

package com.etwin.gateway.shopping.utils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.SocketException;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;

/**
* @describe 读取FTP上的文件
* @auto li.wang
* @date 2013-11-18 下午4:07:34
*/
public class FtpUtils {

private FTPClient ftpClient;
private String fileName, strencoding;
private String ip = "113.108.96.3";        // 服务器IP地址
private String userName = "test";        // 用户名
private String userPwd = "test";        // 密码
private int port = 21;      // 端口号
private String path = "/SZX348/OPFQ/";        // 读取文件的存放目录

/**
* init ftp servere
*/
public FtpUtils() {
this.reSet();
}

public void reSet() {
// 以当前系统时间拼接文件名
fileName = "20131112114850793835861000010161141169.txt";
strencoding = "UTF-8";
this.connectServer(ip, port, userName, userPwd, path);
}

/**
* @param ip
* @param port
* @param userName
* @param userPwd
* @param path
* @throws SocketException
* @throws IOException function:连接到服务器
*/
public void connectServer(String ip, int port, String userName, String userPwd, String path) {
ftpClient = new FTPClient();
try {
// 连接
ftpClient.connect(ip, port);
// 登录
ftpClient.login(userName, userPwd);
if (path != null && path.length() > 0) {
// 跳转到指定目录
ftpClient.changeWorkingDirectory(path);
}
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

/**
* @throws IOException function:关闭连接
*/
public void closeServer() {
if (ftpClient.isConnected()) {
try {
ftpClient.logout();
ftpClient.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
}
}

/**
* @param path
* @return function:读取指定目录下的文件名
* @throws IOException
*/
public List<String> getFileList(String path) {
List<String> fileLists = new ArrayList<String>();
// 获得指定目录下所有文件名
FTPFile[] ftpFiles = null;
try {
ftpFiles = ftpClient.listFiles(path);
} catch (IOException e) {
e.printStackTrace();
}
for (int i = 0; ftpFiles != null && i < ftpFiles.length; i++) {
FTPFile file = ftpFiles[i];
if (file.isFile()) {
fileLists.add(file.getName());
}
}
return fileLists;
}

/**
* @param fileName
* @return function:从服务器上读取指定的文件
* @throws ParseException
* @throws IOException
*/
public String readFile() throws ParseException {
InputStream ins = null;
StringBuilder builder = null;
try {
// 从服务器上读取指定的文件
ins = ftpClient.retrieveFileStream(fileName);
BufferedReader reader = new BufferedReader(new InputStreamReader(ins, strencoding));
String line;
builder = new StringBuilder(150);
while ((line = reader.readLine()) != null) {
System.out.println(line);
builder.append(line);
}
reader.close();
if (ins != null) {
ins.close();
}
// 主动调用一次getReply()把接下来的226消费掉. 这样做是可以解决这个返回null问题
ftpClient.getReply();
} catch (IOException e) {
e.printStackTrace();
}
return builder.toString();
}

/**
* @param fileName function:删除文件
*/
public void deleteFile(String fileName) {
try {
ftpClient.deleteFile(fileName);
} catch (IOException e) {
e.printStackTrace();
}
}

/**
* @param args
* @throws ParseException
*/
public static void main(String[] args) throws ParseException {
FtpUtils ftp = new FtpUtils();
String str = ftp.readFile();
System.out.println(str);
}
}