Java操作IO对象流进行数据的读写

Java操作IO对象流进行数据的读写

对象的读写

使用ObjectInputStream和ObjectOutputStream读写对象(序列化与反序列化)。

只有字节流没有字符流

.类必须实现Serializable接口

给类加个序列化编号，给类定义一个标记，新的修改后的类还可以操作曾经序列化的对象

静态是不能被序列化的，序列化只能对堆中的进行序列化 ，不能对“方法区”中的进行序列化

不需要序列化的字段前加 transient

小例子：

先创建一个Dog对象并序列化:

package com.uwo9.test03;

import java.io.Serializable;

public class Dog implements Serializable {

private static final long serialVersionUID = 2809685095868158625L;

String name;

String color;

}

再创建一个Student对象并序列化：

package com.uwo9.test03;

import java.io.Serializable;

public class Student implements Serializable {

private static final long serialVersionUID = 9078616504949971001L;

static public String schoolName;

private transient String name;

private transient int age;

private double score;

private Dog dog;

public Student() {

super();

}

public Student(String name, int age, double score, Dog dog) {

super();

this.name = name;

this.age = age;

this.score = score;

this.dog = dog;

}

public String getName() {

returnYutTHzPIk name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public double getScore() {

return score;

}

public void setScore(double score) {

this.score = score;

}

@Overridehttp://

public String toString() {

return "Student [name=" + name + ", age=" + age + ", score=" + score + "]";

}

}

将数据写入对象流并存入文件

package com.uwo9.test03;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.ObjectOutputStream;

import java.util.ArrayList;

import java.util.Collections;

public class Test01 {

public static void main(String[] args) {

Dog dog = new Dog();

dog.name = "大黄";

dog.color = "Yellow";

Student student1 = new Student("学生1", 18, 99,dog);

Student student2 = new Student("学生2", 19, 99,dog);

Student student3 = new Student("学生3", 20, 99,dog);

Student.schoolName = "某某大学";

File file = new File("E:/Temp/Test1.txt");

ObjectOutputStream oos = null;

try {

oos = new ObjectOutputStream(new FileOutputStream(file));

//oos.writeObject(student);

ArrayList arrayList = new ArrayList<>();

Collections.addAll(arrayList, student1,student2,student3);

oos.writeObject(arrayList);

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally {

try {

oos.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

从指定文件中读取对象

package com.uwo9.test03;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.util.ArrayList;

public class Test02 {

public static void main(String[] args) {

// 从指定的文件中读取对象

File file = new File("E:/Temp/Test1.txt");

ObjectInputStream ois=null;

try {

ois = new ObjectInputStream(new FileInputStream(file));

// 读取对象

// Student stu = (Student)ois.readObject();

// System.out.println("读取到的数据为:"+stu);

@SuppressWarnings("unchecked")

ArrayList arrayList = (ArrayList) ois.readObject();

for (Student student : arrayList) {

System.out.println(student);

}

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

} catch (ClassNotFoundException e) {

e.printStackTrace();

}finally {

try {

ois.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

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