Recently, you need to compare two object properties, one of which is oldobj, and the other is that Newobj,oldobj is the previous state of newobj, so you need to copy one of the same objects in a state of newobj, because Java does not support deep copy, So specifically wrote a method
The implementation of the method is simple and offers two ways:
One is to serialize to a stream of data, provided that all objects (objects contained in the object ...) are serialized. You need to inherit the serializable interface, and if you inherit it, it's easy, if you don't inherit it, and you don't want to modify all the classes, you can use the second way.
The second is to serialize the object into JSON, using JSON to implement the copy, which requires the use of net.sf.json.JSONObject.
The specific code is as follows:
Copy Code code as follows:
public class Deepcopy {
/**
* Deep Copy
*
* @param <T>
* @param obj
* @return
* @throws Exception
*/
public static <T> t copy (T obj) throws Exception {
//Whether the serialization interface is implemented, even if the class is implemented, the object he owns may not have ...
if (Serializable.class.isAssignableFrom (Obj.getclass ()) {
//If the subclass does not inherit the interface, this step will be an error
try {
return copyimplserializable (obj);
catch (Exception e) {
//Here does not handle, will run to the following try JSON
}
}
//If serialization fails, try JSON serialization method
if (Hasjson ()) {
try {
return Copybyjson (obj);
catch (Exception e) {
//Here is not handled, the following returns null
}
}
return null;
}
/**
* Deep copy-requires class inheritance serialization interface
* @param <T>
* @param obj
* @return
* @throws Exception
*/
@SuppressWarnings ("unchecked")
public static <T> t copyimplserializable (t obj) throws Exception {
Bytearrayoutputstream BAOs = null;
ObjectOutputStream oos = null;
Bytearrayinputstream Bais = null;
ObjectInputStream ois = null;
Object o = null;
//If the subclass does not inherit the interface, this step will be an error
try {
BAOs = new Bytearrayoutputstream ();
Oos = new ObjectOutputStream (BAOs);
oos.writeobject (obj);
Bais = new Bytearrayinputstream (Baos.tobytearray ());
OIS = new ObjectInputStream (Bais);
o = Ois.readobject ();
return (T) O;
} catch (Exception e) {
throw new Exception ("object contains objects with no inheritance serialization");
} finally{
try {
Baos.close ();
Oos.close ();
Bais.close ();
Ois.close ();
} catch (Exception E2) {
//There is no need to deal with the error
}
}
}
/**
* Can I use JSON
* @return
*/
private Static Boolean Hasjson () {
try {
class.forname ("Net.sf.json.JSONObject");
return true;
catch (Exception e) {
return false;
}
}
/**
* Deep copy-requires Net.sf.json.JSONObject
* @param <T>
* @param obj
* @return
* @throws Exception
*/
@SuppressWarnings ("unchecked")
public static <T> t Copybyjson (t obj) throws Exception {
return (T) Jsonobject.tobean (Jsonobject.fromobject (obj), Obj.getclass ());
}
}
You only need to invoke the Copy method on the line.
