classloader

[vijayabaskar]

Hey i have create servlet container using osgi framework. i have multiple war files and then i extract it.. after extract the war it has multiple class files.. i have doubt on how to get multiple war files in main function and the how to get class files using classloader.. i hope you will help me to develope my project..

classByte = loadClassData(classPath);
System.out.println("classpath"+classByte.length );
result = defineClass(className,classByte,0,classByte.length );
System.out.println("classes"+classes);
classes.put(className,result);
System.out.println("return"+result);
return result;

but the result only return null value.. i need to get the classname in claspath.. so help to find..

[Eranga]

i need to get the classname in claspath.. so help to find..

Can you explain a bit more what you want to do here?

[vijayabaskar]

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

//import sun.awt.image.ByteInterleavedRaster;
//import sun.misc.URLClassPath;

/**
* A custom class loader that loads servlets on the fly
*
* @author Adarsh
* @author Sivaraman
*/
public class CustomClassLoader extends ClassLoader {


/**
* classPath contains the CLASSPATH system variable
*/
private String classPath;

/**
* main() method is used to Test this class loader as a standalone application
*/

// public static void main(String[] args) {

// CustomClassLoader cl = new CustomClassLoader();
// //Class cls = cl.getClass("/home/adarsh/sample/WEB-INF/classes/mypackage/Hello.class", "mypackage.Hello");
// Class cls = cl.getClass("D:\\QRD\\deployer\\wars\\sample\\WEB-INF\\classes\\mypackage\\Hello.class", "mypackage.Hello");
// try {
// HttpServlet hs = (HttpServlet) cls.newInstance();
// } catch (InstantiationException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// } catch (IllegalAccessException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
// }

/**
* Returns the class requested for
*
* @param classPath The classPath system variable
* @param className The className is the complete class name the user requested for
*/

public Class getClass(String classPath, String className) {
this.classPath = classPath;
return loadClass(className, true);
}

/**
* Returns the class bytes
*/

private byte[] getBytes() throws IOException {
File f = new File(classPath);
long len = f.length();
byte raw[] = new byte[(int) len];
FileInputStream fis = new FileInputStream(f);
int r = fis.read(raw);
if (r != len)
System.out.println("cant read");
fis.close();
return raw;

}

/**
* (non-Javadoc)
*
* @param name The complete class name
* @param resolve boolean value indicating whether the class should be resolved
* @see ClassLoader#loadClass(String, boolean)
*/

protected Class loadClass(String name, boolean resolve) {
System.out.println(name);
Class clazz = null;
try {
// Load the class from the JVM
clazz = CustomClassLoader.class.getClassLoader().loadClass (name);
return clazz;
} catch (ClassNotFoundException e) {
System.out.println(name + " Not Found in current directory");
}
byte raw[] = null;
try {
// Get the raw bytes of the class
raw = getBytes();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}


clazz = defineClass(name, raw, 0, raw.length);

return clazz;
}

}




CustomClassLoader cc = new CustomClassLoader();
contexts[0][1]=classpath
contexts[0][2]=org.qrd.openmayyam.helloworld
Class cls = cc.getClass(contexts[j][1], contexts[j][2]);

i need to get only the class name that means hellowold..
now am getting only null
please help to fine

[vijayabaskar]

try {
// Load the class from the JVM
clazz = CustomClassLoader.class.getClassLoader().loadClass (name);
return clazz;
} catch (ClassNotFoundException e) {
System.out.println(name + " Not Found in current directory");
}


this only throwing exception

[vijayabaskar]

do u have any idea

[vijayabaskar]

how to class name form class path using classloader

[vijayabaskar]

how to get class name form class path using classloader

[Eranga]

Did you read the Java API for classloader? I'm mess-up what you exactly want to do is. Load the class on last code segment(in try-catch block) And now something different.

ClassLoader (Java 2 Platform SE v1.4.2)

[vijayabaskar]

hi eranga.. i read it.. but now i have to put the list of servlet class files in hashtable and get from hashtable.. can u sent me the example program for it..