Use urlclassloader to dynamically load all jar files in the specified path

Package test. tool. Gui. dbtool. util;

Import java. Io. file;
Import java.net. malformedurlexception;
Import java.net. url;
Import java.net. urlclassloader;
Import org. Apache. log4j. Logger;
Import test. tool. Gui. dbtool. consts. const;

Public class jarloadutil {

Private Static logger log = logger. getlogger (jarloadutil. Class );
Private Static URL lib_url = classloader. getsystemclassloader (). getresource ("lib ");
Private Static urlclassloader loader = NULL;
/*
* Load all jar files in the lib directory and return the corresponding urlclassloader.
*/
Public static urlclassloader geturlclassloader (){

If (loader = NULL ){
String filenames [] = listfilenames ();
If (filenames! = NULL & filenames. length> 0 ){
URL URLs [] = new URL [filenames. Length];
For (INT I = 0; I <filenames. length; I ++ ){
Try {
URLs [I] = new URL (lib_url + "/" + filenames [I]);
} Catch (malformedurlexception e ){
If ("true". Equals (configutil. getconfinfo (). Get (Const. is_log) + "")){
Log. Error ("An error occurred while loading the JAR file in the lib directory! ", E );
}
Throw new runtimeexception ("An error occurred while loading the JAR file in the lib directory! ", E );
}
}
Loader = new urlclassloader (URLs );
}
}
Return loader;
}
/*
* Query the names of all files in the lib directory.
*/
Private Static string [] listfilenames (){
File file_directory = new file ("lib ");
Return file. List ();
}
}

 

Usage:

 

Urlclassloader loader = jarloadutil. geturlclassloader ();
Class <?> Clazz = loader. loadclass (Ds. getdriverclassname ());
Driver driver = (driver) clazz. newinstance ();

Properties P = new properties ();
P. Put ("user", DS. GetUserName ());
P. Put ("password", DS. getpwd ());

Connection con = driver. Connect (Ds. geturl (), P );