IO流习题

习题1

(1)在判断e盘下是否有文件夹mytemp ,如果没有就创建mytemp(2)在e:\lmytemp目录下,创建文件hello.txt
(3)如果hello.txt已经存在，提示该文件已经存在，就不要再重复创(4)并且在hello.txt文件中，写入hello,world~

代码1

package file;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

public class Homework01 {
    public static void main(String[] args) {
        String dirPath = "E:\\mytemp";
        File dirfile = new File(dirPath);
        if (dirfile.exists()){
            String filePath = "E:\\mytemp\\hello.txt";
            File file = new File(filePath);
            if (file.exists()){
                System.out.println("该文件已存在，请勿重复创建！");
            }else {
                try {
                    file.createNewFile();
                    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(filePath));
                    bufferedWriter.write("hello,world");
                    System.out.println("成功写入！");
                    bufferedWriter.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }else {
            dirfile.mkdir();
            System.out.println("文件创建成功！");
        }
    }
}

运行结果1

习题2

要求:使用BufferedReader读取一个文本文件，为每行加上行号,再连同内容一并输出到屏幕上.

代码

package file;

import java.io.*;

public class Homework02 {
    public static void main(String[] args) throws IOException {
        String filePath = "E:\\mytemp\\test.txt";
        BufferedReader br = new BufferedReader(new FileReader(filePath));//读
        try {
            String line;
            int lineNum = 0;
            while ((line = br.readLine()) != null){
                System.out.println(++lineNum + " " + line);
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            br.close();
        }
    }
}

运行结果

习题3

题目描述

(1)要编写一个dog.properties
name=tom
age=5
color=red
(2)编写Dog类(name,age,color)创建一个dog对象，读取dog.成属性初始化，并输出
(3)将创建的Dog对象，序列化到文件dog.dat文件

代码2

package file;

import java.io.*;
import java.util.Properties;

public class Homework03 {
    public static void main(String[] args) throws IOException {
        Properties properties = new Properties();
       /* properties.setProperty("name","tom");
        properties.setProperty("age","5");
        properties.setProperty("corlor","red");
        properties.store(new FileWriter("\\src\\file\\dog.propperties"),"小狗tom的配置文件");*/
        String filePath = "src\\file\\dog.propperties";
        properties.load(new FileReader(filePath));
        properties.list(new PrintStream(filePath));
        String name = properties.getProperty("name") + "";
        int age = Integer.parseInt(properties.get("age") + "");
        String corlor = properties.getProperty("corlor") + "";


        Dog tom = new Dog(name, age, corlor);
        //System.out.println(tom); //标准输出
       BufferedReader br = new BufferedReader(new FileReader(filePath)); //字符流输出
        String line;
        System.out.println("dog对象的信息：");
        while ((line = br.readLine()) != null){
            System.out.println(line);
        }
        br.close();

        //序列化dog

        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("src\\file\\dog.dat"));
        oos.writeObject(tom);
    }
}

class Dog implements Serializable {
    private String name;
    private  int age;
    private  String corlor;

    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 getCorlor() {
        return corlor;
    }

    public void setCorlor(String corlor) {
        this.corlor = corlor;
    }

    public Dog(String name, int age, String corlor) {
        this.name = name;
        this.age = age;
        this.corlor = corlor;
    }

    @Override
    public String toString() {
        return "Dog{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", corlor='" + corlor + '\'' +
                '}';
    }
}

运行结果3