使用反射 调用更改后的.class 文件

/**
 * @author:         吴永行
 * @dateTime:      2014-2-17 下午8:51:10
 * @description:
 *
 */
package 深入理解java虚拟机.第九章类加载即执行子系统的案例与实战;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;

public class JavaClassExecuter {
    public static String execute(byte[] classByte) throws IOException {
        HackSystem.clearBuffer();
        ClassModifier cm = new ClassModifier(classByte);

        byte[] modiBytes = cm.modifyUTF8Constant("java/lang/System",
         "深入理解java虚拟机/第九章类加载即执行子系统的案例与实战/HackSystem");
        HotSwapClassLoader loader = new HotSwapClassLoader();


        /*OutputStream is = new FileOutputStream("aaa.class");
        is.write(modiBytes);
        is.close();
        */

        Class clazz = loader.loadByte(modiBytes);

        try {
            Method method = clazz.getMethod("main",
             new Class[] { String[].class });
            method.invoke(null, new String[] { null });
        } catch (Throwable e) {
            // TODO: handle exception
            e.printStackTrace(HackSystem.out);
        }
        return HackSystem.getBufferString();

    }
}