技術標籤：JAVA之IO流

1.1 練習案例：java物件流和檔案流的相互轉換

1）將若干個Student物件,若干個Teacher物件,寫出到d:/0404/a.txt中
2）將該檔案中所有Student物件反序列化回來裝入List, 所有的Teacher物件反序列化回來轉入另外一個List

程式碼邏輯：建立一個Person類，並實現Serializable。再讓Student和Teacher類繼承Person。（當然這裡沒必要，可以直接建立Student和Teacher類）
運用知識點：物件流，檔案流

（1）Person類：

package Homework;

import java.io.
 
Serializable;

public class Person implements Serializable {
    private static final long serialVersionUID = 1L;
    private String name;
    private String sex;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
 

    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return
 
 "Person [name=" + name + ", sex=" + sex + ", age=" + age + "]";
    }
    public Person(String name, String sex, int age) {
        super();
        this.name = name;
        this.sex = sex;
        this.age = age;
    }
    public Person() {
        super();
    }

}

（2）Student類：

package Homework;

public class Student extends Person {
    public Student(String name,String sex,int age){
        super(name, sex, age);
    }
    public Student(){}
    @Override
    public String toString() {
        return "Student [getName()=" + getName() + ", getSex()=" + getSex() + ", getAge()=" + getAge() + "]";
    }   
}

（3）Teacher類：

package Homework;

public class Teacher extends Person {
    public Teacher(String name,String sex,int age){
        super(name, sex, age);
    }
    public Teacher(){}
    @Override
    public String toString() {
        return "Teacher [getName()=" + getName() + ", getSex()=" + getSex() + ", getAge()=" + getAge() + "]";
    }
}

（4）測試類：

package Homework;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;

public class Test1and2 {

    public static void main(String[] args) {
        //在本工程下建立一個資料夾
        File file=new File("Instance");
        file.mkdirs();
        //在本工程下建立的資料夾下建立一個a.txt檔案，用來寫入物件
        File file2=new File(file,"a.txt");

        //使用物件流寫入物件
        ObjectOutputStream oos=null;
        ObjectInputStream ois=null;
        try {
            file2.createNewFile();

            //將若干個Student物件,若干個Teacher物件,寫入檔案中
            oos=new ObjectOutputStream(new FileOutputStream(file2));
            oos.writeObject(new Student("李四","男",20));
            oos.writeObject(new Student("李四2","男",45));
            oos.writeObject(new Student("李四3","男",38));
            oos.writeObject(new Teacher("張三","男",13));
            oos.writeObject(new Teacher("張三","男",50));
            oos.writeObject(new Teacher("張三","男",34));
            oos.flush();

            //將該檔案中所有Student物件反序列化回來裝入List
            ois=new ObjectInputStream(new FileInputStream(file2));
            ArrayList<Student> list=new ArrayList<>();
            ArrayList<Teacher> list2=new ArrayList<>();

            //將檔案中寫入的物件讀取出來，並轉為物件，存入對應的集合中
            for(int i=0;i<6;i++){
                if(i<=2){
                    Student student=(Student)ois.readObject();
                    list.add(student);
                }else {
                    Teacher teacher=(Teacher)ois.readObject();
                    list2.add(teacher);
                }
            }

            //遍歷打印出集合中的物件
            for (Student student : list) {
                System.out.println(student);
            }
            for (Teacher teacher : list2) {
                System.out.println(teacher);
            }


        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(ois!=null){
                try {
                    ois.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(oos!=null){
                try {
                    oos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}

（5）結果