javac：如何在多个目录中编译多个类？

Question

I'm trying to create a client-server architecture and I want use only javac to compile my code. I'd like to have these directories tree:

/Project/Server/src/Server.java
                   /ClientConnection.java
               /bin/Server.class
                   /ClientConnection.Class

        /Global/src/Constants.java
                   /Packet.java
               /bin/Constants.class
                   /Packet.Class

        /Client/src/(it doesn't matter at the moment)
               /bin/(it doesn't matter at the moment)

I want to use the Constant and the Packet classes either in the server than in the client but with javac I'm not able to do it. I really can't understand how packages and import keyword work. For example I can't understand why the code below is wrong:

Small Server code piece:

import Global.src.Constants;
import Server.src.*

public class Server extends ThreadPoolExecutor{
   private Iterator<ClientConnection> iterator;
   private NodeServer[] map;
   private ServerSocket listener;
   private ArrayList<ClientConnection> clients;
   private HashSet<ClientConnection> clientsDisconnected;

Commands to compile and relative errors:

javac -sourcepath ~/Documenti/Project Server.java

Server.java:1: error: cannot access Constants
   import Global.src.Constants;
             ^
bad source file: /home/francesco/Documenti/Project/Global/src/Constants.java
file does not contain class Global.src.Constants
Please remove or make sure it appears in the correct subdirectory of the sourcepath.

Can anyone help me to have the directories structure previously described?

Thank you in advance!

Seashell I like your solution but I don't understand how to applay it. I crated the common.jar file but I don't know how to import it. Futhermore I don't got whether I need to create a package yet. Could you give me any clarifications please?

Answer 1

try this for multiple files.

javac file1.java file2.java (space is needed b/w file names)

or for all files in the current directory

javac *

Answer 2

Do it following way. In your case, your codes have dependencies (server depends on global, client will probably depend on global and server). You need to compile things in order.

javac -d Project/Global/bin Project/Global/src/*.java
javac -d Project/Server/bin -cp Project/Global/bin Project/Server/src/*

This way, Global codes will be placed inside bin and will be used during Server compilation via class path.

In case you want to use javac and you have nested directories inside your sources, you can use find

find Project/Global/src "*.java" -exec javac -d Project/Global/bin {} \;

As for the error:

Server.java:1: error: cannot access Constants
   import Global.src.Constants;

I guess you want to have slightly different source structure. Eg

Project
  +-Global
    +-src
      +-some_package

and then, inside Constants.java you can put

/* Constants.java */

package some_package;

public class Constants { ... }

Then, inside your code you want to import

import some_package.Constants;