[JAVA] Stream 직렬화와 읽고 쓰기

1. 직렬화와 역직렬화란? 

직렬화 Serialization
object를 binary 형태의 파일로 바꾸는거
컴퓨터는 0과 1로 구성되어 있기 때문에 binary형태로 바꿔주는것이 필요
.bin이나 ser(Serialization)


역직렬화 Deserialization
Binary형태의 파일을 Object로 생성하는것


직렬화가 필요한이유?
- 저장이 필요하기 때문에

 

 

* JAVA

 

http://javadevwannabe.blogspot.com/2012/02/high-level-streams.html

 

- InputStream

FileOutputStream fsOut = new FileOutputStream("binFile.bin");
ObjectOutputStream osOut = new ObjectOutputStream(fsOut);
osOut.writeObject(student);
osOut.close(); //close를 하지 않으면 메모리 누수 현상 발생 

 

- OutputStream

 
FileInputStream fsIn = new FileInputStream("binFile.bin");
ObjectInputStream osIn = new ObjectInputStream(fsIn);
Student clone = (Student) osIn.readObject();     

 

-  전체코드 

package programming;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
 
class Student implements Serializable{
    /**
     * 
     */
    
    private static final long serialVersionUID = 1112261190310944806L;
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getMajor() {
        return major;
    }
    public void setMajor(String major) {
        this.major = major;
    }
    
    public Student(int id, String name, String major) {
        this.id=id;
        this.name = name;
        this.major = major; 
    }
        
    private int id;
    private String name;
    private String major;
        
}
 
 
 
public class programm {
 
    public static void main(String[] args) throws IOException, ClassNotFoundException {
 
        
        Student student = new Student(7777,"name","major");
        System.out.println(student.getId());
        
        
        FileOutputStream fsOut = new FileOutputStream("binFile.bin");
        ObjectOutputStream osOut = new ObjectOutputStream(fsOut);
        osOut.writeObject(student);
        osOut.close(); //close를 하지 않으면 메모리 누수 현상 발생 
 
 
        FileInputStream fsIn = new FileInputStream("binFile.bin");
        ObjectInputStream osIn = new ObjectInputStream(fsIn);
        Student clone = (Student) osIn.readObject();         
        
        osIn.close();
        
        System.out.println(clone.getId() + " " + clone.getMajor());
    
    }
    
 
    
}

 

 

* C#

* python 

 

 

 

2. 텍스트 파일 읽고 쓰기

*JAVA

 

# Write

- BufferedWriter 사용 

- write("~~");  // 쓰기

- newLine(); // Enter 

- flush(); // 기억하고 있다가 메모장에 사용 

- close(); // JAVA의 경우 열면 다시 닫아줘야함. 

 

//Write
Path note = Paths.get("note.txt");
try {
    BufferedWriter writer = Files.newBufferedWriter(note, StandardCharsets.UTF_8 );
    writer.write("Today's weather is good"); 
    writer.newLine();
    writer.write("How are you? ");
    writer.flush(); //memory and write 
    writer.close();             
} catch (IOException e1) {
    // TODO Auto-generated catch block
    e1.printStackTrace();
}

 

# Read 

- BufferedReader 사용 

- readLine(); 

- close(); Buffered사용시 닫기 

Path book = Paths.get("book.txt");
 
try {
    
    BufferedReader reader = Files.newBufferedReader(book);
    System.out.println(reader.readLine());
    System.out.println(reader.readLine());
    
    //반복문을 통해서 읽어본다
    String line = reader.readLine();
            
    while(line!=null) {
        System.out.println(line);
        line = reader.readLine(); 
        
    }
 
    reader.close();
 
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    System.out.println("could not read the file");
}

 

 

 

 

 

 

<출처>

1.www.youtube.com/watch?v=BlMttZXA2cc&list=PLENYGEQnz1xrMzGAfcCJFBzkBNzY2ufb1&index=37

2.