Java源码

				package AM.vm_impl.util;
				
				
				/**
				 * Created by IntelliJ IDEA. User: yellowicq Date: 2004-4-27 Time: 13:16:40
				 * To change this template use File | Settings | File Templates.
				 */
				
				
				import java.io.*;
				
				public class SystemClassLoader
				    extends ClassLoader {
				
				    // basePath gives the path to which this class
				    // loader appends "/.class" to get the
				    // full path name of the class file to load
				    private String basePath;
				
				    public SystemClassLoader(String basePath) {
				
				        this.basePath = basePath;
				    }
				
				    public SystemClassLoader(ClassLoader parent, String basePath) {
				
				        super(parent);
				        this.basePath = basePath;
				    }
				
				    protected Class findClass(String className)
				        throws ClassNotFoundException {
				
				        byte classData[];
				
				        // Try to load it from the basePath directory.
				        classData = getTypeFromBasePath(className);
				        if (classData == null) {
				            throw new ClassNotFoundException();
				        }
				
				        // Parse it
				        return defineClass(className, classData, 0,
				            classData.length);
				    }
				
				    private byte[] getTypeFromBasePath(String typeName) {
				
				        FileInputStream fis;
				        String fileName = basePath + File.separatorChar
				            + typeName.replace('.', File.separatorChar)
				            + ".class";
				
				        try {
				            fis = new FileInputStream(fileName);
				        }
				        catch (FileNotFoundException e) {
				            return null;
				        }
				
				        BufferedInputStream bis = new BufferedInputStream(fis);
				
				        ByteArrayOutputStream out = new ByteArrayOutputStream();
				
				        try {
				            int c = bis.read();
				            while (c != -1) {
				                out.write(c);
				                c = bis.read();
				            }
				        }
				        catch (IOException e) {
				            return null;
				        }
				
				        return out.toByteArray();
				    }
				}