获取java对象地址的一个工具类
By:Roy.LiuLast updated:2019-10-25
一个获取java对象地址的工具类:
import java.lang.reflect.Field;
import sun.misc.Unsafe;
public class Addresser {
private static Unsafe unsafe;
static
{
try
{
Field field = Unsafe.class.getDeclaredField("theUnsafe");
field.setAccessible(true);
unsafe = (Unsafe)field.get(null);
}
catch (Exception e)
{
e.printStackTrace();
}
}
public static long addressOf(Object o)
throws Exception
{
Object[] array = new Object[] {o};
long baseOffset = unsafe.arrayBaseOffset(Object[].class);
int addressSize = unsafe.addressSize();
long objectAddress;
switch (addressSize)
{
case 4:
objectAddress = unsafe.getInt(array, baseOffset);
break;
case 8:
objectAddress = unsafe.getLong(array, baseOffset);
break;
default:
throw new Error("unsupported address size: " + addressSize);
}
return(objectAddress);
}
public static void main(String... args)
throws Exception
{
Object mine = "Hi there".toCharArray();
Object another = "Hi there".toCharArray();
long address = addressOf(mine);
long addressAnother = addressOf(another);
Object mine2 = mine;
long addressMine2 = addressOf(mine);
System.out.println("mine Addess: " + address);
System.out.println("mine2 Addess: " + addressMine2);
System.out.println("another Addess: " + addressAnother);
//Verify address works - should see the characters in the array in the output
printBytes(address, 27);
}
public static void printBytes(long objectAddress, int num)
{
for (long i = 0; i < num; i++)
{
int cur = unsafe.getByte(objectAddress + i);
System.out.print((char)cur);
}
System.out.println();
}
}
From:一号门
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