将文件或者图片保存在FTP服务器上，使用commons-net包。

import java.io.File;  import java.io.FileInputStream;  import java.io.IOException;  import java.io.InputStream;     import org.apache.commons.net.ftp.FTP;  import org.apache.commons.net.ftp.FTPClient;  import org.apache.commons.net.ftp.FTPFile;     public class FTPUploader {         public String username = "";      public String password = "";      public String ip = "";      public Integer port = 21;         public FTPUploader(String username, String password, String ip, int port) {          this.username = username;          this.password = password;          this.ip = ip;          this.port = port;      }         public void upload(File file, String remoteFileName, String remoteFilePath)              throws Exception {          upload(ip, port, username, password, file, remoteFilePath,                  remoteFileName);      }         private void upload(String ip, int port, String userName, String password,              File file, String remotePathName, String remoteName)              throws Exception {          FTPClient ftpClient = new FTPClient();          try {              ftpClient.connect(ip, port);              ftpClient.login(userName, password);              ftpClient.setFileType(FTP.BINARY_FILE_TYPE);              ftpClient.enterLocalPassiveMode();              upload(ftpClient, file, remotePathName, remoteName);          } catch (Exception e) {              throw new Exception("upload to ftp faild");          } finally {              if (ftpClient != null && ftpClient.isConnected()) {                  try {                      ftpClient.disconnect();                  } catch (IOException e) {                  }              }          }      }         private void upload(FTPClient ftpClient, File file, String remotePathName,              String remoteName) throws Exception {          changeDirectory(ftpClient, remotePathName);          uploadFile(ftpClient, file, remotePathName, remoteName);          backToRootDirectory(ftpClient);      }         private void changeDirectory(FTPClient ftpClient, String path)              throws IOException {          int nextSeperator = path.indexOf("/", 1);          String currentPath = null;          if (nextSeperator < 0) {              nextSeperator = path.length();              currentPath = path.substring(1, nextSeperator);              changeDirectory0(ftpClient, currentPath);              return;          } else {              currentPath = path.substring(1, nextSeperator);              changeDirectory0(ftpClient, currentPath);              changeDirectory(ftpClient, path.substring(nextSeperator));          }      }         private void changeDirectory0(FTPClient ftpClient, String path)              throws IOException {          if (!ftpClient.changeWorkingDirectory(path)) {              ftpClient.makeDirectory(path);          }          ftpClient.changeWorkingDirectory(path);      }         private void backToRootDirectory(FTPClient ftpClient) throws IOException {          ftpClient.changeWorkingDirectory("/");      }         private void uploadFile(FTPClient ftpClient, File file,              String remotePathName, String remoteName) throws Exception {          String localPathName = file.getAbsolutePath();          FTPFile[] files = ftpClient.listFiles(remoteName);          if (files.length == 1) {              if (!ftpClient.deleteFile(remoteName)) {                  throw new Exception("fail to delete remote file ["                          + remotePathName + "] before uploading");              }          }          File f = new File(localPathName);          InputStream is = new FileInputStream(f);          if (!ftpClient.storeFile(remoteName, is)) {              is.close();          }          is.close();      }  }

测试

import java.io.File;     import org.junit.Before;  import org.junit.Test;     import com.isharec.jutils.ftp.FTPUploader;     public class FTPUploaderTest {         private FTPUploader ftpUploader;         @Before      public void before() {          ftpUploader = new FTPUploader("username", "password",                  "ip", 21);      }         @Test      public void testUploader() {          File f = new File("E:\\123.txt");          try {              ftpUploader.upload(f, "123.txt", "/aaa/test/");          } catch (Exception e) {              e.printStackTrace();          }      }  }