Java編譯與2班

Question

這是一些非常簡單的Java OOP，但我還沒有在一段時間做這從另一個

引用一個Java類的時候......我得到「沒有找到符號」一個錯誤級＃1：

package toaV2; 

import java.sql.Connection; 

public class vehicle_model 
{ 
    public db_model DB; 
    public Connection conn; 

    public static void main(String[] args) { 
     vehicle_model v = new vehicle_model("system"); 
    } 

    public vehicle_model(String sys) {  
     DB = new db_model(sys); 
     conn = DB.connect(); 

     if(conn != null) { 
      System.err.println("Got a connection."); 
     } 
     else { 
      System.err.println("Couldn't get a connection...");   
     } 
    } 
} 

類＃2：

package toaV2; 

import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.SQLException; 

public class db_model 
{ 
    private static String driver = "com.mysql.jdbc.Driver"; 

    private static String dbUser = "user"; 
    private static String dbPass = "pass"; 
    private static String dbUrl = "jdbc:mysql://url"; 

    private static String system; 
    public static Connection conn; 

    public db_model(String sys) 
    { 
     system = sys; 
    } 

    public static Connection connect() 
    { 
     conn = null; 
     try 
     { 
      String dbName = system.toUpperCase(); 
      String dbHost = dbUrl + dbName; 

      Class.forName(driver).newInstance(); 
      conn = DriverManager.getConnection(dbUrl, dbUser, dbPass); 
     } 
     catch(Exception e) 
     { 
      System.err.println("Exception: " + e.getMessage()); 
     } 

     return conn; 
    } 
} 

而且錯誤，我得到的編譯：

 
$ javac vehicle_model.java 
vehicle_model.java:10: cannot find symbol 
symbol : class db_model 
location: class toaV2.vehicle_model 
    public db_model DB; 
      ^
vehicle_model.java:24: cannot find symbol 
symbol : class db_model 
location: class toaV2.vehicle_model 
     DB = new db_model(system); 
         ^
2 errors 

Answer 1

您必須編譯兩個文件中相同的命令，像

javac vehicle_model.java db_model.java 

Answer 2

你需要在編譯時提供classpath到其他java文件。 即javac的-classpath路徑/到/ Class2中vehicle_model.java