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Object stream of i/o operation (serialization and deserialization)

2022-07-28 11:32:00 【51CTO】

       
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I/O Object flow of practice （ Serialization and deserialization ）_ The data transfer

1、 Why do you need object flow ？

During data transfer , Our previous operation is to read and write the content value of the file . However, we often do data transmission in the front and back end, often in the object body , That is, how to transfer data with a custom built object . So we need to use object flow here .

2、 Why serialization is needed ？

There is a saying that ： We build an object with 16 Base to build an object , Computers read and write data in binary , If we use objects directly for transmission , It will happen that the computer cannot read the data correctly , Then errors may occur in the transmission process . So we need to serialize the object first , The object will then be deserialized and reconstructed at the other end of the transport . This process can be understood as decomposition and reorganization .

3、 example

First of all, we need to build an object for object transmission .

       
       import 
       
       java.
       
       io.
       
       Serializable;
       
       // implements Serializable   The object can be written 
       
       public 
       
       class 
       
       Person 
       
       implements 
       
       Serializable {    
       
       // Customize （ Display definition ） Serial number  
       
       // Prevent objects from serializing later , The structure of the class has changed   Cannot deserialize 
       
       public 
       
       static 
       
       final 
       
       long 
       
       serialVersionUID
       
       =
       
       342343423l;
       
       private 
       
       static 
       
       String 
       
       name; 
       
       // Static variables are not serialized 
       
       public 
       
       transient  
       
       int 
       
       age; 
       
       // add transient The attributes of keywords will not be serialized  transient  transient 
       
       public 
       
       String 
       
       getName() {
       
       return 
       
       name;
       
    }
       
       public 
       
       void 
       
       setName(
       
       String 
       
       name) {
       
       this.
       
       name 
       
       = 
       
       name;
       
    }
       
       public 
       
       int 
       
       getAge() {
       
       return 
       
       age;
       
    }
       
       public 
       
       void 
       
       setAge(
       
       int 
       
       age) {
       
       this.
       
       age 
       
       = 
       
       age;
       
    }
       
       public 
       
       Person()
       
    {}
       
       public 
       
       Person(
       
       String 
       
       name,
       
       int 
       
       age)
       
    {
       
       this.
       
       name
       
       =
       
       name;
       
       this.
       
       age
       
       =
       
       age;
       
    }    
       
       public 
       
       String 
       
       toString()
       
    {
       
       return 
       
       "Person[name="
       
       +
       
       this.
       
       name
       
       +
       
       ",age="
       
       +
       
       this.
       
       age
       
       +
       
       "]";
       
    }
       
}
      
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       // Write an object  ( Serializing objects )
       
       // Use of object output stream 
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/object.txt");
       
       // Create an object output stream 
       
       FileOutputStream 
       
       fileOutputStream;
       
       try {
       
       fileOutputStream 
       
       = 
       
       new 
       
       FileOutputStream(
       
       file);
       
       ObjectOutputStream 
       
       objectOutputStream
       
       =
       
       new 
       
       ObjectOutputStream(
       
       fileOutputStream);
       
       // establish person object 
       
       Person 
       
       person
       
       =
       
       new 
       
       Person(
       
       "yaoming",
       
       36);
       
       // Write object 
       
       objectOutputStream.
       
       writeObject(
       
       person);
       
       // Closed flow 
       
       objectOutputStream.
       
       close();
       
       fileOutputStream.
       
       close();
       
    } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
    } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
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I/O Object flow of practice （ Serialization and deserialization ）_ serialize _02

       
       // Create an object input stream   Read in an object ( Deserialize object   Refactoring objects )
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/object.txt");
       
       FileInputStream 
       
       fileInputStream;
       
       try {
       
       fileInputStream 
       
       = 
       
       new 
       
       FileInputStream(
       
       file);
       
       ObjectInputStream 
       
       objectInputStream
       
       =
       
       new 
       
       ObjectInputStream(
       
       fileInputStream);
       
       Person 
       
       person
       
       =(
       
       Person)(
       
       objectInputStream.
       
       readObject());
       
       System.
       
       out.
       
       println(
       
       person);
       
       objectInputStream.
       
       close();
       
       fileInputStream.
       
       close();
       
  } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
  } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
  } 
       
       catch (
       
       ClassNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
      
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