ObjectInputStream(对象输入流)继承于InputStream,ObjectOutputStream(对象输出流)继承于OutputStream。对象流是将对象的基本数据和图形实现持久存储。ObjectOutputStream实际是在对流进行序列化操作,ObjectInputStream实际是在对流进行反序列化操作,要实现序列化,必须实现Serializable接口,否则是无法进行序列化和反序列化的,如果对象中的属性加了transient和static关键字的话,则该属性不会被序列化。
常用的方法是:readObject(),从ObjectInputStream读取对象;writeObject(Object obj),将指定的对象写入ObjecctOutputStream;close(),关闭该流,其它的一些方法可以自己查询API;
下面通过实例代码来对其进行学习:
先创建一个对象
import java.io.Serializable;
/*
* 为测试对象流创建一个对象
*/
public class Student implements Serializable{
/**
*
*/
private static final long serialVersionUID = 6271405124073931152L;
private String name;
private int age;
private transient String info1;
private static String info2;
public Student() {
}
public Student(String name, int age, String info1, String info2) {
super();
this.name = name;
this.age = age;
this.info1 = info1;
this.info2 = info2;
}
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;
}
public String getInfo1() {
return info1;
}
public void setInfo1(String info1) {
this.info1 = info1;
}
public static String getInfo2() {
return info2;
}
public static void setInfo2(String info2) {
Student.info2 = info2;
}
@Override
public String toString() {
return "Student [name=" + name + ", age=" + age + ", info1=" + info1 + "]" + ", info2=" + info2 + "]";
}
}
①写入对象
@Test
public void t1() throws Exception{
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("H:\\javaio\\objecttest.txt"));
oos.writeInt(10);
oos.writeObject(new String("测试1"));
oos.close();
}
②读取对象
@Test
public void t2() throws Exception{
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("H:\\javaio\\objecttest.txt"));
int readint = ois.readInt();
Object obj = ois.readObject();
System.out.println(readint);
System.out.println(obj);
ois.close();
}
③写入一个Student对象
@Test
public void t3() throws Exception{
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("H:\\javaio\\objecttest.txt"));
oos.writeObject(new Student("测试",18,"信息1","信息2"));
oos.close();
}
④读取对象
@Test
public void t4() throws Exception{
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("H:\\javaio\\objecttest.txt"));
Student stu = (Student) ois.readObject();
System.out.println(stu);
ois.close();
}
我对info1加了transient修饰,对info2加了static修饰,这两个属性在序列化的时候,都不会被序列化。不会被序列化,也就意味着在进行反序列化操作的时候,这两个属性是无法反序列化出结果的,会显示null。