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() {
  return 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;
 }
 @Override
 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<Student> 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<Student> arrayList = (ArrayList<Student>) 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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