Java IO流--练习

1）将若干个Student对象,若干个Teacher对象,写出到d:/0404/a.txt中
2）将该文件中所有Student对象反序列化回来装入List, 所有的Teacher对象反序列化回来转入另外一个List

运用知识点：对象流，文件流

代码：
逻辑—–>建立一个Person类，并实现Serializable。再让Student和Teacher类继承Person。（当然这里没必要，可以直接建立Student和Teacher类）

Person类

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();    }}

Student类

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() + "]";    }   }

Teacher类

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() + "]";    }}

测试类

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) {        //在本工程下创建一个文件夹        File file=new File("Instance");        file.mkdirs();        //在本工程下创建的文件夹下创建一个a.txt文件，用来写入对象        File file2=new File(file,"a.txt");        //使用对象流写入对象        ObjectOutputStream oos=null;        ObjectInputStream ois=null;        try {            file2.createNewFile();            //将若干个Student对象,若干个Teacher对象,写入文件中            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("张三","男",13));            oos.writeObject(new Teacher("张三","男",50));            oos.writeObject(new Teacher("张三","男",34));            oos.flush();            //将该文件中所有Student对象反序列化回来装入List            ois=new ObjectInputStream(new FileInputStream(file2));            ArrayList<Student> list=new ArrayList<>();            ArrayList<Teacher> list2=new ArrayList<>();            //将文件中写入的对象读取出来，并转为对象，存入对应的集合中            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);                }            }            //遍历打印出集合中的对象            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();                }            }        }    }}

遍历结果：

3）要求从控制台输入两个整数，之后完成两个整数的加法操作

如果输入整数，求和。如果输入的不是整数：重新输入，比如ddd

注意：要求使用标准流，不能使用Scanner类

代码：

package com.qf.demo2;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;public class Test {    public static void main(String[] args) {        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));         int sum = 0;        while(true){            try {                System.out.println("请输入第一个数：");                String a = reader.readLine();                System.out.println("请输入第二个数：");                String b = reader.readLine();                //对输入的内容进行正则匹配，判断是否是数字                boolean flag = a.matches("[0-9]+");                boolean flag2 = b.matches("\\d+");                // 如果两次输入的都是数字，那么将两次输入的数据转为整数，并求和，以及退出循环                if( flag && flag2){                    sum = Integer.parseInt(a)+Integer.parseInt(b);                    break;                }else{                    // 如果两次输入有一个不是数字，则重新输入，进入循环                    System.out.println("请重新输入,必须只能包含数字");                }            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        System.out.println("输入的两个整数和是："+sum);    }}

运行结果：