Java對對象的序列化和反序列化

Java提供了將對象以字節的形式寫入到磁盤中，在需要的時候在從磁盤中恢復的功能，在網絡傳輸中非常有用，下面將代碼貼上，分別用兩種形式實現了對象的序列化，其中第二種當時能將指定的變量序列化，更加人性化的隨心所欲

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
/**


@use 實現對對象的序列化和反序列化
@author Bird
/
public class Data {
 public static void writeObject() throws Exception{
 Worm worm = new Worm("Bird");
 ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("d://worm.out"));
 out.writeObject(worm);
 out.close();//關閉的同時也刷新清空了緩沖區

 }


public static void readObject() throws Exception{
    ObjectInputStream in = new ObjectInputStream(new FileInputStream("d://worm.out"));
    Worm s2 = (Worm) in.readObject();
    System.out.println(s2);
}

public static void main(String[] args) throws Exception{
//  writeObject();
    readObject();
}

}
class Worm implements Serializable{

private static final long serialVersionUID = 1L;
private String name = null;
public Worm(String name){
    this.name = name;
}

public String toString(){
    return name;
}

}
 </pre> 

 下面這是第二種方式
import java.io.Externalizable;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
/**


@use 第二種可控制序列化變量個數的方式
@author Bird
/
public class Blip3 implements Externalizable {
 private int i;
 private String s;//沒有實例化
 public Blip3(){

 System.out.println("Blip3 Constructor!!");

}
 //注意  這里的s沒有實例化
public Blip3(String x, int a){

 System.out.println("Blip3(String x, int a)");
 s = x;
 i = a;
 //s  和 i實例化在非默認構造函數中

}
public String toString(){

 return s + i;

}
public void writeExternal(ObjectOutput out){//可選擇寫入變量

 System.out.println("Blip3.writeExternal");
 try {
     out.writeObject(s);
     out.writeInt(i);
 } catch (IOException e) {
     throw new RuntimeException(e);
 }//必須進行這兩項，否則就一個變量也不出初始化

}
public void readExternal(ObjectInput in){//可選擇讀入數據

 System.out.println("Blip3.readExternal");
 try {
     s = (String)in.readObject();
     i = in.readInt();
 } catch (ClassNotFoundException e) {

 } catch (IOException e) {
 throw new RuntimeException(e);
 }


}
public void read() throws FileNotFoundException, IOException, ClassNotFoundException{//讀取序列化的類

 ObjectInputStream in = new ObjectInputStream(new FileInputStream("d://Blip3.out"));
 System.out.println("Revovering  b3");
 Blip3 b3 = (Blip3)in.readObject();
 System.out.println(b3);

}
public void write() throws Exception{//寫入對象

 Blip3 b3 = new Blip3("A String", 47);
 System.out.println(b3);
 ObjectOutputStream o = new ObjectOutputStream(new FileOutputStream("d://Blip3.out"));
 System.out.println("Saving Object");
 o.writeObject(b3);
 o.close();

}
public static void main(String[] args) throws Exception{

 Blip3 b = new Blip3();
 //  b.write();
 b.read();

}
}
</pre>