为避免GC的负效应, 使用DirectByteBuffer管理原始(Raw)数据会为高负载的系统带来性能的提升. DirectByteBuffer默认是由GC来回收的, 这通常能够满足需求, 若要想自己控制回收的时机, 可以使用这段代码.
Java代码
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* {@link DirectByteBufferCleaner}
*
* @author <a href=mailto:zhong.lunfu@gmail.com>zhongl</a>
* @created 2011-1-14
*/
public final class DirectByteBufferCleaner {
private DirectByteBufferCleaner() {}
public static void clean(final ByteBuffer byteBuffer) {
if (!byteBuffer.isDirect()) return;
try {
Object cleaner = invoke(byteBuffer, "cleaner");
invoke(cleaner, "clean");
} catch (Exception e) { /* ignore */ }
}
private static Object invoke(final Object target, String methodName) throws Exception {
final Method method = target.getClass().getMethod(methodName);
return AccessController.doPrivileged(new PrivilegedAction<Object>() {
@Override
public Object run() {
try {
return method.invoke(target);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
});
}
}
http://www.buildapp.net/java/show.asp?id=10000
Java代码
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* {@link DirectByteBufferCleaner}
*
* @author <a href=mailto:zhong.lunfu@gmail.com>zhongl</a>
* @created 2011-1-14
*/
public final class DirectByteBufferCleaner {
private DirectByteBufferCleaner() {}
public static void clean(final ByteBuffer byteBuffer) {
if (!byteBuffer.isDirect()) return;
try {
Object cleaner = invoke(byteBuffer, "cleaner");
invoke(cleaner, "clean");
} catch (Exception e) { /* ignore */ }
}
private static Object invoke(final Object target, String methodName) throws Exception {
final Method method = target.getClass().getMethod(methodName);
return AccessController.doPrivileged(new PrivilegedAction<Object>() {
@Override
public Object run() {
try {
return method.invoke(target);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
});
}
}
http://www.buildapp.net/java/show.asp?id=10000
本文介绍如何通过使用DirectByteBuffer管理原始数据,避免垃圾回收的负效应,从而为高负载系统带来性能提升。提供了Java代码实现,包括导入依赖、自定义类DirectByteBufferCleaner及其方法clean,用于控制内存回收的时机。
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