Java之IO(七)ObjectInputStream和ObjectOutputStream

public class Student implements Serializable{

	/**
	 * 
	 */
	private static final long serialVersionUID = 4484961141733473265L;
	private int id;
	private String name;
	private int age;
	
	public Student(int id, String name, int age) {
		this.id = id;
		this.name = name;
		this.age = age;
	}
	
	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 int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
	}
	
}

public class Teacher implements Serializable{
	
	/**
	 * 
	 */
	private static final long serialVersionUID = -312001656457242689L;
	private int age;
	private String name;
	private Student student;
	
	public Teacher(int age, String name, Student student) {
		this.age = age;
		this.name = name;
		this.student = student;
	}
	
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Student getStudent() {
		return student;
	}
	public void setStudent(Student student) {
		this.student = student;
	}

	@Override
	public String toString() {
		return "Teacher [age=" + age + ", name=" + name + ", student=" + student + "]";
	}
	
}

    @Test
	public void test() throws IOException {
		Student student = new Student(10, "张三", 12);
		Teacher teacher = new Teacher(32, "李四", student);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ObjectOutputStream oos = new ObjectOutputStream(baos);
		oos.writeObject(teacher);
		byte[] obj = baos.toByteArray();
		System.out.println(obj.length);
		System.out.println(Arrays.toString(obj));
		ByteArrayInputStream bais = new ByteArrayInputStream(obj);
		ObjectInputStream ois = new ObjectInputStream(bais);
		try {
			Teacher t = (Teacher) ois.readObject();
			System.out.println(t);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

public class Classroom implements Externalizable {
	
	private Teacher teacher;
	
	private List<Student> students;

	@Override
	public void writeExternal(ObjectOutput out) throws IOException {
		out.writeObject(teacher);
		out.writeObject(students);
	}

	@SuppressWarnings("unchecked")
	@Override
	public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
		this.teacher = (Teacher) in.readObject();
		this.students = (List<Student>) in.readObject();
	}

	public Teacher getTeacher() {
		return teacher;
	}

	public void setTeacher(Teacher teacher) {
		this.teacher = teacher;
	}

	public List<Student> getStudents() {
		return students;
	}

	public void setStudents(List<Student> students) {
		this.students = students;
	}

	@Override
	public String toString() {
		return "Classroom [teacher=" + teacher + ", students=" + students + "]";
	}
	
}

    @Test
	public void test2() throws IOException {
		Student student = new Student(10, "张三", 12);
		Teacher teacher = new Teacher(32, "李四", student);
		Classroom classroom = new Classroom();
		List<Student> students = new ArrayList<Student>();
		students.add(student);
		classroom.setStudents(students);
		classroom.setTeacher(teacher);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ObjectOutputStream oos = new ObjectOutputStream(baos);
		oos.writeObject(classroom);
		byte[] obj = baos.toByteArray();
		System.out.println(obj.length);
		System.out.println(Arrays.toString(obj));
		ByteArrayInputStream bais = new ByteArrayInputStream(obj);
		ObjectInputStream ois = new ObjectInputStream(bais);
		try {
			Classroom c = (Classroom) ois.readObject();
			System.out.println(c);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

    @Test
	public void test3() throws IOException {
		Student student = new Student(10, "张三", 12);
		Teacher teacher = new Teacher(32, "李四", student);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ObjectOutputStream oos = new ObjectOutputStream(baos);
		oos.writeObject(student);
		oos.writeObject(teacher);
		byte[] obj = baos.toByteArray();
		System.out.println(obj.length);
		System.out.println(Arrays.toString(obj));
		ByteArrayInputStream bais = new ByteArrayInputStream(obj);
		ObjectInputStream ois = new ObjectInputStream(bais);
		try {
			Student s = (Student) ois.readObject();
			System.out.println(s);
			Teacher t = (Teacher) ois.readObject();
			System.out.println(t);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

    @Test
	public void test4() throws IOException {
		String path = ObjectStreamTest.class.getClassLoader().getResource("").getPath() + "objectstream.txt";
//		System.out.println(path);
		File file = new File(path);
		Student student = new Student(10, "张三", 12);
		Teacher teacher = new Teacher(32, "李四", student);
		FileOutputStream fos = new FileOutputStream(file);
		ObjectOutputStream oos = new ObjectOutputStream(fos);
		oos.writeObject(student);
		oos.writeObject(teacher);
		oos.flush();
		oos.close();
		FileInputStream fis = new FileInputStream(new File(path));
		@SuppressWarnings("resource")
		ObjectInputStream ois = new ObjectInputStream(fis);
		try {
			Student s = (Student) ois.readObject();
			System.out.println(s);
			Teacher t = (Teacher) ois.readObject();
			System.out.println(t);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}