以编程方式计算Java对象占用的内存,包括它引用的对象

import java.lang.instrument.Instrumentation;

public class ObjectSizeAgent {
    private static Instrumentation instrumentation;

    public static void premain(String agentArgs, Instrumentation inst) {
        instrumentation = inst;
    }

    public static long getObjectSize(Object o) {
        return instrumentation.getObjectSize(o);
    }
}

import com.google.common.primitives.Ints;

public class Main {
    public static void main(String[] args) {
        MyClass obj = new MyClass();
        int size = Ints.checkedCast(SizeOf.deepSizeOf(obj));
        System.out.println("Size of " + obj.getClass() + " is " + size + " bytes");
    }
}