+30 IO 라이브러리: ObjectInputStream, ObjectOutputStream

1. Serializable, ObjectOutputStream, FileOutputStream

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.*;
class Sawon implements Serializable
{
	private int sabun;
	private String name;
	private String dept;
	
	public int getSabun() {
		return sabun;
	}
	public void setSabun(int sabun) {
		this.sabun = sabun;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getDept() {
		return dept;
	}
	public void setDept(String dept) {
		this.dept = dept;
	}
	
}
public class M1 {

	public static void main(String[] args) {
		
		Sawon sa = new Sawon();
		sa.setSabun(1);
		sa.setName("김");
		sa.setDept("개발부");
		
		try
		{
			// ArrayList 자체 저장 -> stringTokenizer, split 사용 필요X
			FileOutputStream fos = new FileOutputStream("c:\\사원\\object.txt"); // 파일 쓰기
			ObjectOutputStream oos = new ObjectOutputStream(fos);
			
			oos.writeObject(sa);
			
			oos.close();
			fos.close();
			
			System.out.println("객체 단위 저장 완료!!");
			
		} catch(Exception ex) {}
		
	}
}

 

깨져서 나옴

 

 

 

2.

import java.io.FileInputStream;
import java.io.ObjectInputStream;

public class M2 {

	public static void main(String[] args) {
		
		try
		{
			FileInputStream fis = new FileInputStream("c:\\사원\\object.txt");
			ObjectInputStream ois = new ObjectInputStream(fis);
			
			Sawon sa = (Sawon)ois.readObject();
			
			System.out.println(sa.getDept());
			System.out.println(sa.getName());
			System.out.println(sa.getSabun());
			
		} catch(Exception ex) {}
	}
}

개발부
김
1

 

 

3. 직렬화로 평균 구하기

import java.util.*;
import java.io.*;

class Student implements Serializable
{
	private int hakbun;
	private String name;
	private int kor, eng, math;
	
	public int getHakbun() {
		return hakbun;
	}
	public void setHakbun(int hakbun) {
		this.hakbun = hakbun;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getKor() {
		return kor;
	}
	public void setKor(int kor) {
		this.kor = kor;
	}
	public int getEng() {
		return eng;
	}
	public void setEng(int eng) {
		this.eng = eng;
	}
	public int getMath() {
		return math;
	}
	public void setMath(int math) {
		this.math = math;
	}
	
	// 매개변수 있는 생성자
	public Student(int hakbun, String name, int kor, int eng, int math) {
		this.hakbun = hakbun;
		this.name = name;
		this.kor = kor;
		this.eng = eng;
		this.math = math;
	}
	
}

public class M3 {

	public static void main(String[] args) {
		
		ArrayList<Student> list = new ArrayList<Student>();
		
		list.add(new Student(1, "김", 80, 90, 70));
		list.add(new Student(2, "이", 82, 92, 72));
		list.add(new Student(3, "박", 83, 93, 73));
		list.add(new Student(4, "최", 84, 94, 74));
		list.add(new Student(5, "유", 85, 95, 75));
		
		// 저장
		try
		{
			FileOutputStream fos = new FileOutputStream("c:\\사원\\student.txt");
			ObjectOutputStream oos = new ObjectOutputStream(fos);
			
			oos.writeObject(list);
			oos.close();
			fos.close();
			
			System.out.println("저장 완료!!");
		
		} catch(Exception ex) {}
	}
}

import java.util.*;
import java.io.*;
public class M4 {

	public static void main(String[] args) {
		
		try
		{
			FileInputStream fis = new FileInputStream("c:\\사원\\student.txt");
			ObjectInputStream ois = new ObjectInputStream(fis);
			ArrayList<Student> list = (ArrayList<Student>)ois.readObject();
			
			for(Student s:list)
			{
				System.out.println
				(
					s.getHakbun() + " "
					+ s.getName() + " "
					+ s.getKor() + " "
					+ s.getEng() + " "
					+ s.getMath() + " "
					+ (s.getKor() + s.getEng() + s.getMath()) + " "
					+ String.format("%.2f", (s.getKor() + s.getEng() + s.getMath())/3.0));
				
			}
			
		} catch(Exception ex) {}
	}
}

1 김 80 90 70 240 80.00
2 이 82 92 72 246 82.00
3 박 83 93 73 249 83.00
4 최 84 94 74 252 84.00
5 유 85 95 75 255 85.00

 

 

4. IO 응용