偏移地址

public class  {

    public static Unsafe getInstance() throws Exception {
        Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe");
        unsafeField.setAccessible(true);
        return (Unsafe) unsafeField.get(null);
    }
}

// VO.java
public class VO {
    public static int a = 1;
    private long b = 19l;
}

// OffsetTest.java
public class OffsetTest {

    public static void main(String[] args) {
        try {
            Unsafe unsafe = UnsafeUtils.getInstance();
            long aFieldOffset = unsafe.staticFieldOffset(VO.class.getField("a"));
            long bFieldOffset = unsafe.objectFieldOffset(VO.class.getDeclaredField("b"));
            System.out.println("aFieldOffset is: " + aFieldOffset);
            System.out.println("bFieldOffset is: " + bFieldOffset);
            VO vo = new VO();
            long bFieldValue = unsafe.getLong(vo, bFieldOffset);
            System.out.println("bFieldValue is: " + bFieldValue);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}