Java中序列化流的基本使用

序列化流

• 高级流
• 需要依托低级流
• ObjectOutputStream
• ObjectInputStream

ObjectOutputStream

• 将java对象写入文件

• 基本用法

  @Test
  public void objectOutputStreamTest(){
      try {
          FileOutputStream outputStream = new FileOutputStream("E:/ObjectOutputStreamTest.txt");
          //使用低级流初始化ObjectOutputStream
          ObjectOutputStream oos = new ObjectOutputStream(outputStream);
          //将对象写入文件中（注：该类必须实现Serializable接口）
          oos.writeObject(new Student("赵玉龙", 3));
          //释放资源 
          oos.close();
      } catch (IOException e) {
          e.printStackTrace();
      }
  }
  

ObjectInputStream

• 从从文件中读取java对象

• 基本用法

  @Test
  public void objectInputStreamTest(){
      try {
          FileInputStream inputStream = new FileInputStream("E:/ObjectOutputStreamTest.txt");
          //使用低级流初始化ObjectInputStream
          ObjectInputStream ois = new ObjectInputStream(inputStream);
          Student student = (Student) ois.readObject();
          ois.close();
          System.out.println(student);
      } catch (IOException | ClassNotFoundException e) {
          e.printStackTrace();
      }
  }
  

案例：将java对象写入文件后读取它

@Test
public void writeObjects(){
    //实例化一组java对象
    List<Student> students = new ArrayList<>();
    students.add(new Student("张三", 3));
    students.add(new Student("李四", 3));
    students.add(new Student("王五", 3));
    try {
        //实例化一个ObjectOutputStream对象用来写
        FileOutputStream outputStream = new FileOutputStream("E:/writeObjects.txt");
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(outputStream);
        //将一组java对象放到List中后写入文件
        objectOutputStream.writeObject(students);
        objectOutputStream.close();
        //实例化一个ObjectInputStream对象用来读
        FileInputStream inputStream = new FileInputStream("E:/writeObjects.txt");
        ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
        //从文件中将之前写入的List读取到一个新的List对象中
        List<Student> studentList = new ArrayList<>();
        studentList = (List<Student>) objectInputStream.readObject();
        
        System.out.println(studentList);
    } catch (IOException | ClassNotFoundException e) {
        e.printStackTrace();
    }
}