java序列化（transient和static修飾的變數的序列化實現）
阿新 • • 發佈：2019-02-02
序列化
(程式碼摘抄自Java程式設計思想)
平常序列化知識不做介紹 把書裡的有意思東西摘抄下來
用transient修飾是變數是否可以序列化？
靜態變數是否可以初始化？
1.用 Externalizable 介面實現序列化（在重寫的writeExternal和readExternal中實現序列化，）
忽視成員變數是否用transient修飾
2.用Serializable實現序列化（
privatevoid writeObject(ObjectOutputStream stream)
throws IOException ;
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException ;
3.1_1）序列化
2.用Serializable實現序列化publicclassBlip3implementsExternalizable{privateint i;privatetransientString s;// No initializationpublicBlip3(){System.out.println("Blip3 Constructor");// s, i not initialized}publicBlip3(String x,int a){System.out.println("Blip3(String x, int a)");s = x;i = a;// s & i initialized only in non-default constructor.}publicString toString(){return s + i;}publicvoid writeExternal(ObjectOutput out)throwsIOException{System.out.println("Blip3.writeExternal");// You must do this:out.writeObject(s);out.writeInt(i);}publicvoid readExternal(ObjectInput in)throwsIOException,ClassNotFoundException{System.out.println("Blip3.readExternal");// You must do this:s =(String)in.readObject();i = in.readInt();}publicstaticvoid main(String[] args)throwsIOException,ClassNotFoundException{System.out.println("Constructing objects:");Blip3 b3 =newBlip3("A String ",47);// Blip3 b3 = new Blip3();System.out.println(b3);ObjectOutputStream o =newObjectOutputStream(newFileOutputStream("Blip3.out"));System.out.println("Saving object:");o.writeObject(b3);o.close();// Now get it back:ObjectInputStream in =newObjectInputStream(newFileInputStream("Blip3.out"));System.out.println("Recovering b3:");b3 =(Blip3)in.readObject();System.out.println(b3);}}/* Output:Constructing objects:Blip3(String x, int a)A String 47Saving object:Blip3.writeExternalRecovering b3:Blip3 ConstructorBlip3.readExternalA String 47*///:~
3.1序列化靜態變數(沒實現靜態變數序列化)publicclassSerialCtlimplementsSerializable{privateString a;privatetransientString b;publicSerialCtl(String aa,String bb){a ="Not Transient: "+ aa;b ="Transient: "+ bb;}publicString toString(){return a +"\n"+ b;}privatevoid writeObject(ObjectOutputStream stream)// public void writeObject(ObjectOutputStream stream)throwsIOException{stream.defaultWriteObject();stream.writeObject(b);}privatevoid readObject(ObjectInputStream stream)// public void readObject(ObjectInputStream stream)throwsIOException,ClassNotFoundException{stream.defaultReadObject();b =(String)stream.readObject();}publicstaticvoid main(String[] args)throwsIOException,ClassNotFoundException{SerialCtl sc =newSerialCtl("Test1","Test2");System.out.println("Before:\n"+ sc);ByteArrayOutputStream buf=newByteArrayOutputStream();ObjectOutputStream o =newObjectOutputStream(buf);o.writeObject(sc);// Now get it back:ObjectInputStream in =newObjectInputStream(newByteArrayInputStream(buf.toByteArray()));SerialCtl sc2 =(SerialCtl)in.readObject();System.out.println("After:\n"+ sc2);}}/* Output:Before:Not Transient: Test1Transient: Test2After:Not Transient: Test1Transient: Test2*///:~
3.1_1）序列化
abstractclassShapeimplementsSerializable{publicstaticfinalint RED =1, BLUE =2, GREEN =3;privateint xPos, yPos, dimension;privatestaticRandom rand =newRandom(