如何解決Java錯誤「系統找不到指定的路徑」？

Question

我正在運行Mac OS X並且代碼正常工作。我的隊友正在運行Windows 7，並且他得到了錯誤（即使他的系統上存在目錄結構和文件）。有任何想法嗎？我已經花了幾個小時對此無法弄清楚。謝謝。

import java.io.BufferedReader; 
import java.io.FileReader; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; // Not used 
import java.sql.ResultSet; // Not used 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.util.ArrayList; // Not used 
import java.util.Scanner; // Not used 

public class CreateDB { 

    public CreateDB() { 
    } 

    public void createDB() { 

     Connection conn = null; 

     String url = "jdbc:mysql://localhost:3306/"; 
     String dbName = ""; // Not used (yet?) 
     String driver = "com.mysql.jdbc.Driver"; 
     String userName = "root"; // Tell user userName is "root". OR/TODO: Change to something more secure? 
     String password = ""; // Tell user password is "". Or/TODO: Change to something more secure? 
     String line; 
     String sqlDump = null; 
     String [] sqlDumpArray; 

     String fileSeperator = System.getProperty("file.separator"); 
     System.out.println("fileSeperator is: " + fileSeperator); // Testing 
     String path = System.getProperty("user.dir"); 
     System.out.println("path is: " + path); // Testing 
     String pathToFile = (path + fileSeperator + "src" + fileSeperator + "files" + fileSeperator); 
     System.out.println("pathToFile is: " + pathToFile); // Testing. 
     String fileName = "create_db_and_tables.sql"; // NOTE: Rename file, if necessary. Make sure it's in right place. 
     System.out.println("pathToFile + fileName is: " + pathToFile + fileName); // Testing. 

     try { 
     Class.forName(driver).newInstance(); 
     conn = DriverManager.getConnection(url, userName, password); 
     System.out.println("Connected to the database.\n"); // Testing 

     BufferedReader reader = new BufferedReader(new FileReader(pathToFile + fileName)); 
     line = reader.readLine(); 
     while (line != null) { 
      sqlDump += line + "\n"; 
      line = reader.readLine(); 
     } 

     System.out.println(sqlDump); // Testing 
     sqlDumpArray = sqlDump.split(";"); 
     System.out.println("sqlDumpArray size is " + sqlDumpArray.length); // Testing 

     for (int i = 0; i < sqlDumpArray.length; i++) { 
      System.out.println("\nsqlDumpArray[" + i + "] is: " + sqlDumpArray[i]); // Testing 
     } 

     for (int j = 1; j < sqlDumpArray.length -1; j++) { 
      try { 
       Statement statement = conn.createStatement(); 
       statement.addBatch(sqlDumpArray[j]); 
       statement.executeBatch(); // Could refactor or us another method 
      } 
      catch (SQLException e) { 
       System.err.println("SQLException: " + e.getMessage()); 

      } 
      catch (Exception e) { 
       System.err.println("Exception: " + e.getMessage()); 
      } 
     } 
     } 
     catch (java.lang.ClassNotFoundException e) { 
     System.err.println("ClassNotFoundException: " + e.getMessage()); 

     } 
     catch (SQLException e) { 
     System.err.println("SQLException: " + e.getMessage()); 

     } 
     catch (Exception e) { 
     System.err.println("Exception: " + e.getMessage()); 
     } 
     finally { 
     try { 
      // conn.commit(); // Not necessary 
      conn.close(); 
      System.out.println("Successfully disconnected from database. Yeah!"); 
     } 
     catch (SQLException e) { 
      System.err.println("SQLException in 'finally' block: " + e.getMessage()); 
     } 
     } 
    } 
    public static void main(String[] args) { 
    CreateDB create = new CreateDB(); 
    create.createDB(); 
    } 
} 

當試圖執行數據庫創建過程時，Windows上的用戶已收到錯誤。

String fileSeperator = System.getProperty("file.separator"); 
System.out.println("fileSeperator is: " + fileSeperator); 
String path = System.getProperty("user.dir"); 
System.out.println("path is: " + path); 
String pathToFile = (path + fileSeperator + "src" + fileSeperator + "files" + fileSeperator); 
System.out.println("pathToFile is: " + pathToFile); 
String fileName = "create_db_and_tables.sql"; 
System.out.println("pathToFile + fileName is: " + pathToFile + fileName); 

這是什麼一個例子：即使在路徑和文件似乎是正確的，比如什麼是下面的System.out.println語句文件中返回（以下高亮顯示）時出現此錯誤在Windows 7計算機上的語句返回：

Exception: C:\Users\USER\workspace\mrbs2011a\src\files\create_db_and_tables.sql (The system cannot find the path specified) 

這被打印出來，即使用戶已經位於「SRC /文件」文件夾中的文件「create_db_and_tables.sql」。

Answer 1

這有可能是文件被鎖定或用戶權限下在Java程序運行不允許訪問該文件。

如果該文件是居然還有，那麼該文件被鎖定（例如正在舉行開放給其他進程寫入）可能是原因。 documentation for FileReader表示如果「指定的文件不存在，是目錄而不是常規文件，或者出於某種其他原因無法打開以供閱讀，則它將拋出FileNotFoundException」。