Use of other streams

  

I / O stream

Data flow ：

/*
     Data flow 
    DataInputStream and DataOutputStream
     effect ： Used for basic data type traversal or string reading and writing 
     */
    @Test
    public void test1() throws IOException {
//         Write operation 
        DataOutputStream dos = new DataOutputStream(new FileOutputStream("data.txt"));
        dos.writeUTF(" Zhang pock ");
        dos.flush();
        dos.writeInt(40);
        dos.flush();
        dos.writeBoolean(true);
        dos.flush();

        dos.close();
//         Got data.txt The file cannot be read directly 
    }
    @Test
    //       Read the variables in the file into memory 
    public void test2() throws IOException {
        DataInputStream dis = new DataInputStream(new FileInputStream("data.txt"));

//       The reading order should be consistent with the order when writing the file 
        String name = dis.readUTF();
        int age = dis.readInt();
        boolean b = dis.readBoolean();
        System.out.println(name+age+b);

        dis.close();
    }

Object flow ：

  serialize ： Write to file

Deserialization ： Write from file to memory

 

  

package ObjectInputOutputStream;

import org.junit.Test;

import java.io.*;

public class ObjectStreamTest {

    /*
        Put... In memory java Objects are saved to disk or transmitted over the network 
        Use ObjectOutputStream Realization 
        */
    @Test
    public void test() throws IOException {
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("ObjectStream.txt"));

        oos.writeObject(new String(" I love China ！"));
        oos.flush();

        oos.close();
    }

    /*
         Deserialization ： Put the disk file （ The Internet ） Objects in are restored to objects in memory 
         Use ObjectInputStream
     */
    @Test
    public void test2() throws IOException, ClassNotFoundException {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("ObjectStream.txt"));

        Object obj = ois.readObject();
        System.out.println(obj);

        ois.close();
    }
}

Class serialization has certain requirements ： One of the following two interfaces must be implemented

 

static,transient The variable of cannot be serialized  

 

If it is not added manually serialVersionUID , After modifying the object ,JVM Of UID The corresponding changes will result in failure to deserialize