[Java] 使用 Apache的 Commons-net库 实现FTP操作

Posted 2020-06-25 Phantom01

    因为最近工作中需要用到FTP操作，而手上又没有现成的FTP代码。就去网上找了一下，发现大家都使用Apache的 Commons-net库中的FTPClient。

    但是，感觉用起来不太方便。又在网上找到了很多封装过的。觉得也不是很好用。于是就自己写了一个。网上大多是例子都是直接对文件进行操作，而我更需要的是读到内存，或者从内存上写。并且有很多实用单例模式，但是我觉得如果调用比较多的话，可能会出现问题。

  1 /**
  2  * 封装了一些FTP操作
  3  */
  4 import java.io.BufferedReader;
  5 import java.io.FileOutputStream;
  6 import java.io.IOException;
  7 import java.io.InputStreamReader;
  8 import java.io.OutputStream;
  9 import java.io.OutputStreamWriter;
 10 
 11 import org.apache.commons.net.ftp.FTP;
 12 import org.apache.commons.net.ftp.FTPClient;
 13 import org.apache.commons.net.ftp.FTPCmd;
 14 import org.apache.commons.net.ftp.FTPReply;
 15 import org.apache.log4j.Logger;
 16 
 17 public class FTPUtil {
 18     private static Logger logger = Logger.getLogger(FTPUtil.class);
 19 
 20     private static FTPClient getConnection() {
 21         FTPClient client = new FTPClient();
 22         client.setDataTimeout(30000);
 23         client.setDefaultTimeout(30000);
 24         return client;
 25     }
 26 
 27     public static FTPClient getConnection(String host) throws IOException {
 28         FTPClient client = getConnection();
 29         client.connect(host);
 30         if (!FTPReply.isPositiveCompletion(client.getReplyCode())) {
 31             throw new IOException("connect error");
 32         }
 33         return client;
 34     }
 35     public static FTPClient getConnection(String host, int port) throws IOException {
 36         FTPClient client = getConnection();
 37         client.connect(host, port);
 38         if (!FTPReply.isPositiveCompletion(client.getReplyCode())) {
 39             throw new IOException("connect error");
 40         }
 41         return client;
 42     }
 43 
 44     static FTPClient getConnection(String host, String username, String password) throws IOException {
 45         FTPClient client= getConnection(host);
 46         client.login(username, password);
 47         if (!FTPReply.isPositiveCompletion(client.getReplyCode())) {
 48             throw new IOException("login error");
 49         }
 50         return client;
 51     }
 52 
 53     static FTPClient getConnection(String host, int port, String username, String password)
 54             throws IOException {
 55         FTPClient client = getConnection(host, port);
 56         client.login(username, password);
 57         if (!FTPReply.isPositiveCompletion(client.getReplyCode())) {
 58             throw new IOException("login error");
 59         }
 60         return client;
 61     }
 62 
 63     /**
 64      * 移动文件(若目标文件存在则不移动，并返回false)
 65      */
 66     static boolean moveFile(String curFileName, String targetFileName, FTPClient client)
 67             throws IOException {
 68         int reply;
 69         reply = client.sendCommand(FTPCmd.RNFR, curFileName);
 70         if (FTPReply.isNegativePermanent(reply)) {
 71             //logger.error("FTP move file error. code:" + reply);
 72             System.out.println("FTP move file error. code:" + reply);
 73             return false;
 74         }
 75         reply = client.sendCommand(FTPCmd.RNTO, targetFileName);
 76         if (FTPReply.isNegativePermanent(reply)) {
 77             //logger.error("FTP move file error. code:" + reply);
 78             System.out.println("FTP move file error. code:" + reply);
 79             return false;
 80         }
 81         return true;
 82     }
 83 
 84     /**
 85      * 读取文件列表
 86      */
 87     @Deprecated
 88     static String[] getFileNameList(FTPClient client) throws IOException {
 89         String names[] = client.listNames();
 90         if (!FTPReply.isPositiveCompletion(client.getReply())) {
 91             throw new IOException("get file name list error");
 92         }
 93         return names;
 94     }
 95 
 96     /**
 97      * 读文件
 98      */
 99     static String readFile(String path, FTPClient client) throws IOException {
100         client.setFileType(FTP.EBCDIC_FILE_TYPE);
101         BufferedReader bf = new BufferedReader(
102                 new InputStreamReader(client.retrieveFileStream(path), "UTF-8"));
103         StringBuilder sb = new StringBuilder();
104         String str;
105         while ((str = bf.readLine()) != null) {
106             sb.append(str).append("\n");
107         }
108         return sb.toString();
109     }
110 
111     @Deprecated
112     static boolean downFile(String remotePath, String localPath, FTPClient client)
113             throws IOException {
114         FileOutputStream fos = new FileOutputStream(localPath);
115         client.setFileType(FTPClient.BINARY_FILE_TYPE);
116         client.retrieveFile(remotePath, fos);
117         return false;
118     }
119 
120     /**
121      * 写文件
122      */
123     static boolean storeAsFile(String context, String remotePath, FTPClient client)
124             throws IOException {
125         OutputStream out = client.storeFileStream(remotePath);
126         OutputStreamWriter writer = new OutputStreamWriter(out, "UTF-8");
127         writer.write(context);
128         writer.flush();
129         writer.close();
130         return true;
131     }
132 
133     static void close(FTPClient client) {
134         try {
135             if (client != null) {
136                 client.disconnect();
137             }
138         } catch (IOException e) {
139 
140         }
141     }
142 }

FTPUtil