优化技术之内存消耗测试

2013-06-29

内存消耗测试

当一个Java应用程序运行时，有很多需要消耗内存的因素存在，如对象、加载类、线程等。在这里只考虑程序中的对象所消耗的虚拟机堆空间，这样我们就可以利用Runtime类的freeMemory()和totalMomery()方法。

public class Handler implements InvocationHandler {

  private Object obj;

  public Handler(Object obj) {

    this.obj = obj;

  }

  public static Object newInstance(Object obj) {

    Object result = Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), new Handler(obj));

    return result;

  }

  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

    Object result;

    try {

      Log.i(“Handler”, "begin method " + method.getName());

      long start = Memory.used();

      result = method.invoke(obj, args);

      long end = Memory.used();

      Log.i(“Handler”, "the method " + method.getName() + “ lasts ” + (end – start) + “ms”);

    } catch (InvocationTargetException e) {

      throw e.getTargetException();

    } catch (Exception e) {

      throw new RuntimeException(“unexpected invocation exception: ” + e.getMessage());

    } finally {

      Log.i(“Handler”, "end method " + method.getName());

    }

  }

}

public class Memory {

  public static long used() {

    long total = Runtime.getRuntime().totalMemory();

    long free = Runtime.getRuntime().freeMemory();

    return (total - free);

  }

}