Question

这是情景：

我在类中实例化了一个String，然后我在HEAP中获得了它的位置：

public class UnsafeExperiment {

    static String s = "ciao";

    public UnsafeExperiment() throws Exception {
        Unsafe unsafe = getUnsafeInstance();
        Field field = this.getClass().getDeclaredField("s");
        field.setAccessible(true);

        long position = unsafe.staticFieldOffset(field);
        wait();

    }

    private  Unsafe getUnsafeInstance() throws Exception {
        Field theUnsafeInstance = Unsafe.class.getDeclaredField("theUnsafe");
        theUnsafeInstance.setAccessible(true);
        return (Unsafe) theUnsafeInstance.get(Unsafe.class);
    }
}

从另一个类，如何使用其地址调用HEAP中的String？（请，我对考虑使用这种方法的机会不感兴趣..我从图书馆了解到它是不安全的）

Answer 1

您可以按如下方式从position访问字符串：

String s = (String) unsafe.getObject(UnsafeExperiment.class, position);

Java：如何从HEAP获取对象？

1 个答案: