对Java解序列化早作防备(三)
e;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import com.ibm.ba.scg.LookAheadDeserializer.Bicycle;
public class LookAheadDeserializer {
private static byte[] serialize(Object obj) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(obj);
byte[] buffer = baos.toByteArray();
oos.close();
baos.close();
return buffer;
}
private static Object deserialize(byte[] buffer) throws IOException,
ClassNotFoundException {
ByteArrayInputStream bais = new ByteArrayInputStream(buffer);
// We use LookAheadObjectInputStream instead of InputStream
ObjectInputStream ois = new LookAheadObjectInputStream(bais);
Object obj = ois.readObject();
ois.close();
bais.close();
return obj;
}
public static void main(String[] args) {
try { www.2cto.com
// Serialize a Bicycle instance
byte[] serializedBicycle = serialize(new Bicycle(0, "Unicycle", 1));
// Serialize a File instance
byte[] serializedFile = serialize(new File("Pierre Ernst"));
// Deserialize the Bicycle instance (legitimate use case)
Bicycle bicycle0 = (Bicycle) deserialize(serializedBicycle);
System.out.println(bicycle0.getName() + " has been deserialized.");
// Deserialize the File instance (error case)
Bicycle bicycle1 = (Bicycle) deserialize(serializedFile);
} catch (Exception ex) {
ex.printStackTrace(System.err);
}
}
}
当运行该应用程序时，在试图去java.io.File的对象进行解序列化之前，JVM就抛出异常，如图1所示：
图1. 应用程序输出
结论
需要记住的是，整棵对象树(根对象，及其所有的成员对象)是在解序列化过程中进行组建的。在更为复杂的情况下，你可能必须允许更多的类可被解序列化。