sun.misc.Unsafe.staticFieldBase()方法的使用及代码示例

x33g5p2x  于2022-01-31 转载在 其他  
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本文整理了Java中sun.misc.Unsafe.staticFieldBase()方法的一些代码示例，展示了Unsafe.staticFieldBase()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Unsafe.staticFieldBase()方法的具体详情如下：
包路径：sun.misc.Unsafe
类名称：Unsafe
方法名：staticFieldBase

Unsafe.staticFieldBase介绍

[英]Returns the base address for accessing some static field in the given class. This method is implemented as follows:

public Object staticFieldBase(Class c) { 
Field[] fields = c.getDeclaredFields(); 
for (int i = 0; i < fields.length; i++) { 
if (Modifier.isStatic(fields[i].getModifiers())) { 
return staticFieldBase(fields[i]); 
} 
} 
return null; 
}

[中]返回访问给定类中某个静态字段的基址。此方法的实现如下：

public Object staticFieldBase(Class c) { 
Field[] fields = c.getDeclaredFields(); 
for (int i = 0; i < fields.length; i++) { 
if (Modifier.isStatic(fields[i].getModifiers())) { 
return staticFieldBase(fields[i]); 
} 
} 
return null; 
}

代码示例

代码示例来源：origin: apache/ignite

/**
 * Returns static field base.
 *
 * @param field Field.
 * @return Static field base.
 */
public static Object staticFieldBase(Field field) {
  return UNSAFE.staticFieldBase(field);
}

代码示例来源：origin: wildfly/wildfly

private static ObjectStreamField[] getDeclaredSerialPersistentFields(Class<?> clazz) {
  final Field field;
  try {
    field = clazz.getDeclaredField("serialPersistentFields");
  } catch (NoSuchFieldException e) {
    return null;
  }
  if (field == null) {
    return null;
  }
  final int requiredModifiers = Modifier.STATIC | Modifier.PRIVATE | Modifier.FINAL;
  if ((field.getModifiers() & requiredModifiers) != requiredModifiers) {
    return null;
  }
  try {
    return (ObjectStreamField[]) unsafe.getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
  } catch (ClassCastException e) {
    return null;
  }
}

代码示例来源：origin: com.google.protobuf/protobuf-java

@Override
 public Object getStaticObject(Field field) {
  return getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
 }
}

代码示例来源：origin: org.apache.ignite/ignite-core

/**
 * Returns static field base.
 *
 * @param field Field.
 * @return Static field base.
 */
public static Object staticFieldBase(Field field) {
  return UNSAFE.staticFieldBase(field);
}

代码示例来源：origin: com.tomitribe.tribestream/tribestream-metrics-bytecode

public static Object staticFieldBase(final Field f) {
  return UNSAFE.staticFieldBase(f);
}

代码示例来源：origin: com.tomitribe.tribestream/tribestream-metrics-bytecode

@Deprecated
public static Object staticFieldBase(final Class<?> aClass) {
  return UNSAFE.staticFieldBase(aClass);
}

代码示例来源：origin: jboss-remoting/jboss-marshalling

private static ObjectStreamField[] getDeclaredSerialPersistentFields(Class<?> clazz) {
  final Field field;
  try {
    field = clazz.getDeclaredField("serialPersistentFields");
  } catch (NoSuchFieldException e) {
    return null;
  }
  if (field == null) {
    return null;
  }
  final int requiredModifiers = Modifier.STATIC | Modifier.PRIVATE | Modifier.FINAL;
  if ((field.getModifiers() & requiredModifiers) != requiredModifiers) {
    return null;
  }
  try {
    return (ObjectStreamField[]) unsafe.getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
  } catch (ClassCastException e) {
    return null;
  }
}

代码示例来源：origin: net.openhft/chronicle-core

private static long maxDirectMemory0() {
  try {
    Class<?> clz;
    if (IS_JAVA_9_PLUS) {
      clz = Class.forName("jdk.internal.misc.VM");
    } else {
      clz = Class.forName("sun.misc.VM");
    }
    final Field f = clz.getDeclaredField("directMemory");
    long offset = UNSAFE.staticFieldOffset(f);
    Object base = UNSAFE.staticFieldBase(f);
    return UNSAFE.getLong(base, offset);
  } catch (Exception e) {
    // ignore
  }
  System.err.println(Jvm.class.getName() + ": Unable to determine max direct memory");
  return 0L;
}

代码示例来源：origin: OpenHFT/Chronicle-Core

private static long maxDirectMemory0() {
  try {
    Class<?> clz;
    if (IS_JAVA_9_PLUS) {
      clz = Class.forName("jdk.internal.misc.VM");
    } else {
      clz = Class.forName("sun.misc.VM");
    }
    final Field f = clz.getDeclaredField("directMemory");
    long offset = UNSAFE.staticFieldOffset(f);
    Object base = UNSAFE.staticFieldBase(f);
    return UNSAFE.getLong(base, offset);
  } catch (Exception e) {
    // ignore
  }
  System.err.println(Jvm.class.getName() + ": Unable to determine max direct memory");
  return 0L;
}

代码示例来源：origin: org.jboss.marshalling/jboss-marshalling

private static ObjectStreamField[] getDeclaredSerialPersistentFields(Class<?> clazz) {
  final Field field;
  try {
    field = clazz.getDeclaredField("serialPersistentFields");
  } catch (NoSuchFieldException e) {
    return null;
  }
  if (field == null) {
    return null;
  }
  final int requiredModifiers = Modifier.STATIC | Modifier.PRIVATE | Modifier.FINAL;
  if ((field.getModifiers() & requiredModifiers) != requiredModifiers) {
    return null;
  }
  try {
    return (ObjectStreamField[]) unsafe.getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
  } catch (ClassCastException e) {
    return null;
  }
}

代码示例来源：origin: io.fastjson/boon

protected UnsafeField ( Field field  )  {
  super(field);
  if ( super.isStatic() ) {
    base = unsafe.staticFieldBase( field );
    offset = unsafe.staticFieldOffset( field );
  } else {
    offset = unsafe.objectFieldOffset( field );
    base = null;
  }
  this.field = field;
}

代码示例来源：origin: org.jboss.marshalling/jboss-marshalling-osgi

private static ObjectStreamField[] getDeclaredSerialPersistentFields(Class<?> clazz) {
  final Field field;
  try {
    field = clazz.getDeclaredField("serialPersistentFields");
  } catch (NoSuchFieldException e) {
    return null;
  }
  if (field == null) {
    return null;
  }
  final int requiredModifiers = Modifier.STATIC | Modifier.PRIVATE | Modifier.FINAL;
  if ((field.getModifiers() & requiredModifiers) != requiredModifiers) {
    return null;
  }
  try {
    return (ObjectStreamField[]) unsafe.getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
  } catch (ClassCastException e) {
    return null;
  }
}

代码示例来源：origin: boonproject/boon

protected UnsafeField ( Field field  )  {
  super(field);
  if ( super.isStatic() ) {
    base = unsafe.staticFieldBase( field );
    offset = unsafe.staticFieldOffset( field );
  } else {
    offset = unsafe.objectFieldOffset( field );
    base = null;
  }
  this.field = field;
}

代码示例来源：origin: boonproject/boon

protected UnsafeField ( Field field  )  {
  super(field);
  if ( super.isStatic() ) {
    base = unsafe.staticFieldBase( field );
    offset = unsafe.staticFieldOffset( field );
  } else {
    offset = unsafe.objectFieldOffset( field );
    base = null;
  }
  this.field = field;
}

代码示例来源：origin: io.advantageous.boon/boon-reflekt

protected UnsafeField ( Field field  )  {
  super(field);
  if ( super.isStatic() ) {
    base = unsafe.staticFieldBase( field );
    offset = unsafe.staticFieldOffset( field );
  } else {
    offset = unsafe.objectFieldOffset( field );
    base = null;
  }
  this.field = field;
}

代码示例来源：origin: com.github.advantageous/boon-reflekt

protected UnsafeField ( Field field  )  {
  super(field);
  if ( super.isStatic() ) {
    base = unsafe.staticFieldBase( field );
    offset = unsafe.staticFieldOffset( field );
  } else {
    offset = unsafe.objectFieldOffset( field );
    base = null;
  }
  this.field = field;
}

代码示例来源：origin: peter-lawrey/Performance-Examples

public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException, IOException, InstantiationException {
    System.out.println("Starting");
    Object o = UNSAFE.staticFieldBase(Unsafe4Demo.class);
    Field _x = Unsafe4Demo.class.getDeclaredField("x");
    _x.setAccessible(true);
    long xOff = UNSAFE.staticFieldOffset(_x);
    UNSAFE.compareAndSwapInt(o, xOff, 5, 42);
    System.out.println("x=" + UNSAFE.getInt(o, xOff) + " x is now " + _x.get(null));

/*
    MyEnum mt = (MyEnum) UNSAFE.allocateInstance(MyEnum.class);
    Field name = Enum.class.getDeclaredField("name");
    name.setAccessible(true);
    name.set(mt, "A");
    System.out.println("Done " + mt);
    System.out.println(mt.equals(MyEnum.A));
*/

  }

代码示例来源：origin: com.github.os72/protobuf-java-shaded-351

@Override
 public Object getStaticObject(Field field) {
  return getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
 }
}

代码示例来源：origin: org.apache.ratis/ratis-proto-shaded

@Override
 public Object getStaticObject(Field field) {
  return getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
 }
}

代码示例来源：origin: io.bitsensor/proto

@Override
 public Object getStaticObject(Field field) {
  return getObject(unsafe.staticFieldBase(field), unsafe.staticFieldOffset(field));
 }
}

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