Java新手尝试基本的FTP。试图将Apache Commons Net FTP教程变成一个可以正常运行的程序，用户可以在其中输入服务器，用户，传递并可以修改/添加/查看/删除文件。
但是，每当我进入“列表文件”命令时，都会收到一个异常错误。错误是：
Exception in thread "main" java.lang.Error: Unresolved compilation problems:
The import org.apache.oro cannot be resolved
The import org.apache.oro cannot be resolved
The import org.apache.oro cannot be resolved
The import org.apache.oro cannot be resolved
The import org.apache.oro cannot be resolved
The import org.apache.oro cannot be resolved
Pattern cannot be resolved to a type
MatchResult cannot be resolved to a type
PatternMatcher cannot be resolved to a type
_matcher_ cannot be resolved
Perl5Matcher cannot be resolved to a type
pattern cannot be resolved
Perl5Compiler cannot be resolved to a type
MalformedPatternException cannot be resolved to a type
result cannot be resolved or is not a field
_matcher_ cannot be resolved
pattern cannot be resolved or is not a field
result cannot be resolved or is not a field
_matcher_ cannot be resolved
result cannot be resolved or is not a field
result cannot be resolved or is not a field
result cannot be resolved or is not a field
result cannot be resolved or is not a field
result cannot be resolved or is not a field
result cannot be resolved or is not a field
result cannot be resolved or is not a field
at org.apache.commons.net.ftp.parser.RegexFTPFileEntryParserImpl.<init>(RegexFTPFileEntryParserImpl.java:19)
at org.apache.commons.net.ftp.parser.ConfigurableFTPFileEntryParserImpl.<init>(ConfigurableFTPFileEntryParserImpl.java:57)
at org.apache.commons.net.ftp.parser.UnixFTPEntryParser.<init>(UnixFTPEntryParser.java:136)
at org.apache.commons.net.ftp.parser.UnixFTPEntryParser.<init>(UnixFTPEntryParser.java:119)
at org.apache.commons.net.ftp.parser.DefaultFTPFileEntryParserFactory.createUnixFTPEntryParser(DefaultFTPFileEntryParserFactory.java:169)
at org.apache.commons.net.ftp.parser.DefaultFTPFileEntryParserFactory.createFileEntryParser(DefaultFTPFileEntryParserFactory.java:94)
at org.apache.commons.net.ftp.FTPClient.initiateListParsing(FTPClient.java:2359)
at org.apache.commons.net.ftp.FTPClient.listFiles(FTPClient.java:2142)
at org.apache.commons.net.ftp.FTPClient.listFiles(FTPClient.java:2188)
at ftpconnecter.FTPConnecter.run(FTPConnecter.java:74)
at ftpconnecter.Main.main(Main.java:11)
该类本身在下面。在makeDir中为路径输入空白行是触发错误的原因。但是，错误消息说它发生在第74行，如果是createDir方法，则为其他情况。也没有列出任何异常，这在Java错误消息中我从未见过。
作为一个附带的问题，用一个大的try-catch块设置这种方法的方法是构造该程序的有效方法吗？
package ftpconnecter;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Scanner;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;
public class FTPConnecter {
public void run() {
Scanner reader = new Scanner(System.in);
while(true) {
System.out.println("Connect to FTP? (Anything other than Yes quits app)");
String input = reader.nextLine();
if (!input.equals("Yes")) {
break;
}
System.out.println("Server address?");
String server = reader.nextLine().trim();
System.out.println("Username");
String user = reader.nextLine();
System.out.println("Password:");
String pass = reader.nextLine();
int port = 21;
FTPClient ftpClient = new FTPClient();
try {
ftpClient.connect(server, port);
showServerReply(ftpClient);
int replyCode = ftpClient.getReplyCode();
if (!FTPReply.isPositiveCompletion(replyCode)) {
System.out.println("Connect failed");
continue;
}
boolean success = ftpClient.login(user, pass);
showServerReply(ftpClient);
if (!success) {
System.out.println("Could not login to the server");
continue;
}
while(true) {
System.out.println("Commands: " + "\n" +
"1. List Files & Directories (L)" + "\n" +
"2. Create New Directory (D)" + "\n" +
"3. Create Nested Directory (N)");
String command = reader.nextLine();
if (command.equals("L")) {
System.out.println("What is the file path? (Press enter for all)");
String filePath = reader.nextLine();
FTPFile[] files = ftpClient.listFiles(filePath);
printFileDetails(files);
} else if (command.equals("D")) {
createDir(ftpClient);
} else if (command.equals("N")) {
System.out.println("What is your directory path?");
String path = reader.nextLine();
makeDir(ftpClient, path);
} else {
break;
}
}
ftpClient.logout();
ftpClient.disconnect();
} catch (IOException ex) {
System.out.println("Oops! Something went wrong");
ex.printStackTrace();
}
}
}
private static void showServerReply(FTPClient ftpClient) {
String[] replies = ftpClient.getReplyStrings();
if (replies != null && replies.length > 0) {
for (String aReply : replies) {
System.out.println("SERVER: " + aReply);
}
}
}
private void createDir(FTPClient ftpClient) throws IOException {
Scanner reader = new Scanner(System.in);
System.out.println("What is the directory to be created?");
String dirToCreate = reader.nextLine();
boolean success = ftpClient.makeDirectory(dirToCreate);
showServerReply(ftpClient);
if (success) {
System.out.println("Successfully created directory: " + dirToCreate);
} else {
System.out.println("Failed to create directory. See server's reply.");
}
}
private void makeDir(FTPClient ftpClient, String dirPath) throws IOException {
String[] pathElements = dirPath.split("/");
if (pathElements != null && pathElements.length > 0) {
for (String singleDir : pathElements) {
boolean exists = ftpClient.changeWorkingDirectory(singleDir);
if (!exists) {
boolean created = ftpClient.makeDirectory(singleDir);
if (created) {
System.out.println("Created directory " + singleDir);
} else {
System.out.println("Could not create directory " + singleDir);
}
}
}
}
}
private void printFileDetails(FTPFile[] files) {
DateFormat dateFormater = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
for (FTPFile file : files) {
String details = file.getName();
if (file.isDirectory()) {
details = "[" + details + "]";
}
details += "\t\t" + file.getSize();
details += "\t\t" + dateFormater.format(file.getTimestamp().getTime());
System.out.println(details);
}
}
}