Java IO（七）- Object流

直接将Object写入或写出

transient关键字

serializable接口

externalizable接口

例子一、

public class Test {

    public static void main(String[] args) {
        try {
            T t = new T();
            t.k = 18;
            FileOutputStream fos = new FileOutputStream("d:/bak/testobjectio.dat");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(t);
            oos.flush();
            oos.close();

            FileInputStream fis = new FileInputStream("d:/bak/testobjectio.dat");
            ObjectInputStream ois = new ObjectInputStream(fis);
            T t2 = (T) ois.readObject();
            System.out.println(t2.i + "//" + t2.j + "//" + t2.d + "//" + t2.k);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}
class T implements Serializable {
    int i = 10;
    int j = 9;
    double d = 2.3;
    int k = 15;
}

结果：

10//9//2.3//18

例子二、

用transient修饰变量k

class T implements Serializable {
    int i = 10;
    int j = 9;
    double d = 2.3;
    transient int k = 15;
}

结果：

10//9//2.3//0

transient修饰的变量k不会被写入进去，所以取出来的k为空，为默认值0