package foo;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class MyLocalClassLoader extends ClassLoader {
private Log log = LogFactory.getLog(this.getClass());
public MyLocalClassLoader() {
super();
}
/* classes文件存放目录 */
private String classesDir;
public MyLocalClassLoader(String classesDir) {
super();
this.classesDir = classesDir;
}
@Override
protected Class findClass(String name) throws ClassNotFoundException {
String classFileName = classesDir + File.separator + StringUtils.replaceChars(name, '.', File.separatorChar) + ".class";
File classF = new File(classFileName);
if (classF.exists()) {
InputStream input = null;
try {
input = FileUtils.openInputStream(classF);
byte[] b = IOUtils.toByteArray(input);
return defineClass(name, b, 0, b.length);
} catch (IOException e) {
log.error(e.getMessage(), e);
} finally {
IOUtils.closeQuietly(input);
}
} else {
log.error(classFileName + "文件不存在！");
}
return super.findClass(name);
}
protected void recursive_loadClass(boolean resolve) throws ClassNotFoundException {
System.out.println("MyLocalClassLoader.recursive_loadClass()");
}
}
测试：
package foo;
import java.lang.reflect.InvocationTargetException;
import java.util.ResourceBundle;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class MyLocalClassLoaderDemo {
private static Log log = LogFactory.getLog(MyLocalClassLoaderDemo.class);
public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException,
SecurityException, IllegalArgumentException, InvocationTargetException {
ResourceBundle res = ResourceBundle.getBundle("foo/conf");
Class clazz = new MyLocalClassLoader(res.getString("classesDir")).loadClass("demo.ClassDemo");
Object obj = clazz.newInstance();
log.info(obj.toString());
clazz = new MyLocalClassLoader(res.getString("classesDir")).loadClass("demo.Parent");
clazz = new MyLocalClassLoader(res.getString("classesDir")).loadClass("demo.Child");
obj = clazz.newInstance();
Class[] cc = {};
Object[] oo = {};
log.info(obj.getClass().getMethod("hello", cc).invoke(obj, oo));
}
}
测试结果：
辅助测试类：
package demo;
public class ClassDemo {
@Override
public String toString() {
return "ClassDemo.toString()";
}
}
package demo;
public abstract class Parent {
public String hello() {
return "Parent.hello()";
}
}
package demo;
public class Child extends Parent {
@Override
public String hello() {
return "Child.hello()";
}
}
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