【SCAU 面向对象程序设计】05文件管理与输入输出

0501显示目录或文件的属性

代码

ShowFile

package ex501.file;

import java.io.File;
import java.util.Date;

public class ShowFile {
    private File file;

    public ShowFile(String fileName) {
        this.file = new File(fileName);
    }

    //统计目录下文件个数
    public int getFileNumber(File directory){
        int num = 0;
        File[] files = directory.listFiles();
        if (files != null) {
            for (File f : files) {
                if (f.isFile()) {
                    num++;
                } else {//是目录的话，访问目录下的文件
                    num+=getFileNumber(f);
                }
            }
        }
        return num;
    }

    //统计目录下目录个数
    public int getDirectoryNumber(File directory){
        int num = 0;
        File[] files = directory.listFiles();
        if(files != null){
            for (File f : files) {
                if (f.isDirectory()) {
                    num++;
                    num+=getDirectoryNumber(f);
                }
            }
        }
        return num;
    }

    //统计目录下文件总大小
    public long getDirectorySize(File directory){
        long size = 0;
        File[] files = directory.listFiles();
        if(files != null){
            for (File f : files) {
                if (f.isFile()) {
                    size += f.length();
                } else {
                    size += getDirectorySize(f);
                }
            }
        }
        return size;
    }

    public void show() {
        if(file.isDirectory()){
            System.out.println("目标名称："+file.getName());
            System.out.println("-----------------");
            System.out.println("目标类型：目录");
            System.out.println("所在位置："+file.getAbsolutePath());
            System.out.println("目录大小："+getDirectorySize(file)+"字节");
            System.out.println("修改时间："+new Date(file.lastModified()));
            System.out.println("包含文件："+getFileNumber(file)+"个");
            System.out.println("包含目录："+getDirectoryNumber(file)+"个");
            System.out.println("目标属性：");
            System.out.println("      可读："+file.canRead());
            System.out.println("      可写："+file.canWrite());
            System.out.println("      可运行："+file.canExecute());
            System.out.println("      隐藏："+file.isHidden());
        }
        else if (file.isFile()){
            System.out.println("目标名称："+file.getName());
            System.out.println("-----------------");
            //获取目标文件类型，例如Main.java文件类型为.java
            String type = file.getName().substring(file.getName().lastIndexOf("."));
            System.out.println("目标类型：文件（"+type+"）");
            System.out.println("所在位置："+file.getAbsolutePath());
            System.out.println("文件大小："+file.length()+"字节");
            System.out.println("修改时间："+new Date(file.lastModified()));
            System.out.println("目标属性：");
            System.out.println("      可读："+file.canRead());
            System.out.println("      可写："+file.canWrite());
            System.out.println("      可运行："+file.canExecute());
            System.out.println("      隐藏："+file.isHidden());

        }
        else {
            System.out.println("["+file.getName()+ "]不是文件或目录名称");
        }
    }


}

Main

package ex501;

import ex501.file.ShowFile;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("输入一个文件名或目录名：");
        String fileName = input.nextLine();
        ShowFile showFile = new ShowFile(fileName);
        showFile.show();

    }
}

---

0502统计Java源程序文件中关键字的使用次数

代码

package ex502.file;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class KeywordsCount {
    private List<String> keywords;
    private Map<String, Integer> keywordsCount;

    public KeywordsCount() {
        this.keywords = new ArrayList<>();
        this.keywordsCount = new HashMap<>();
    }

    //读取keywords.txt关键字
    public void readKeywords(File file){
        try(var reader = Files.newBufferedReader(file.toPath())){
            String line;
            while((line = reader.readLine()) != null){//读取每一行
                keywords.add(line.trim());
                keywordsCount.put(line.trim(), 0);
            }
    } catch (IOException e) {//读取失败
            System.err.println("读取失败:"+e.getMessage());
            System.exit(1);
        }
    }

    //输入文件名，统计其中关键字出现次数
    public void countKeywords(File file){
        try(var reader = Files.newBufferedReader(file.toPath())){
            String line;
            boolean inBlockComment = false;//是否在注释中
            while((line = reader.readLine()) != null){
                line = line.trim();
                if (inBlockComment) {//在注释中
                    if (line.contains("*/")) {//到达注释尾
                        inBlockComment = false;
                        line = line.substring(line.indexOf("*/") + 2).trim();//截取注释尾后的内容
                    } else {
                        continue; // 跳过整个行，如果仍在注释中
                    }
                }
                if (line.startsWith("/*")) {//注释的开始
                    inBlockComment = true;//在注释中
                    if (line.contains("*/")) {
                        inBlockComment = false;
                        line = line.substring(line.indexOf("*/") + 2).trim();
                    } else {
                        continue; // 跳过整个行，如果它开始了一个块注释
                    }
                }
                if (line.startsWith("//")) {
                    continue; // 跳过单行注释
                }
                for(String keyword : keywords){
                    Pattern pattern = Pattern.compile("\\b"+keyword+"\\b");
                    Matcher matcher = pattern.matcher(line);
                    while(matcher.find()){//找到关键字+1
                        keywordsCount.put(keyword, keywordsCount.get(keyword)+1);
                    }
                }
            }
        } catch (IOException e) {
            System.err.println("读取失败:"+e.getMessage());
            System.exit(1);
        }
    }

    //把统计结果存储到文本文件，文件名为“keywords-源程序文件名.txt”，文本文件中每行一个关键字和出现次数，按关键字升序排序
    public void writeKeywordsCount(File file){
        try(var writer = Files.newBufferedWriter(Paths.get("Keywords-"+file.getName()+".txt"))){
            keywordsCount.entrySet().stream()
                    .sorted(Map.Entry.comparingByKey())
                    .forEach(entry -> {
                        try {
                            writer.write(entry.getKey() + "            " + entry.getValue() + "\n");
                        } catch (IOException e) {
                            System.err.println("写入失败:"+e.getMessage());
                            System.exit(1);
                        }
                    });
        } catch (IOException e) {
            System.err.println("写入失败:"+e.getMessage());
            System.exit(1);
        }
    }

    //查看使用次数排名（降序）前n位的关键字并输出。关键字使用相同时，按关键字升序排序
    public void showKeywordsCount(int n){
        keywordsCount.entrySet().stream()
                .sorted((entry1, entry2) -> {
                    if(entry1.getValue().equals(entry2.getValue())){
                        return entry1.getKey().compareTo(entry2.getKey());
                    }else{
                        return entry2.getValue().compareTo(entry1.getValue());
                    }
                })
                .limit(n)
                .forEach(entry -> System.out.println(entry.getKey() + "：" + entry.getValue()));
    }

}

package ex502;

import ex502.file.KeywordsCount;

import java.io.File;
import java.util.Scanner;


public class Main {
    public static void main(String[] args){
        Scanner input = new Scanner(System.in);

        KeywordsCount keywordsCount = new KeywordsCount();

        System.out.print("输入关键字文件名：");
        String fileName1 = input.nextLine();
        File file1 = new File(fileName1);
        keywordsCount.readKeywords(file1);

        System.out.print("输入Java源程序文件名：");
        String fileName2 = input.nextLine();
        File file2 = new File(fileName2);
        keywordsCount.countKeywords(file2);
        keywordsCount.writeKeywordsCount(file2);
        System.out.println(file2.getName()+"的关键字使用次数已经存放到文件Keywords-"+file2.getName()+"中.");
        System.out.print("需要查看排名前几位（范围：1-51）的关键字？");
        int n = input.nextInt();
        keywordsCount.showKeywordsCount(n);


    }
}

---

0503简易地址簿管理程序

代码

Address

package ex503.address;

import java.io.Serializable;

public class Address implements Serializable {
    private String name;
    private String province;
    private String city;
    private String postcode;
    private String detail_address;

    public Address(String name, String province, String city, String postcode, String detail_address) {
        this.name = name;
        this.province = province;
        this.city = city;
        this.postcode = postcode;
        this.detail_address = detail_address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getPostcode() {
        return postcode;
    }

    public void setPostcode(String postcode) {
        this.postcode = postcode;
    }

    public String getDetail_address() {
        return detail_address;
    }

    public void setDetail_address(String detail_address) {
        this.detail_address = detail_address;
    }

    @Override
    public String toString() {
        return "姓名：" + name + "，省份：" + province + "，城市：" + city + "，邮政编码：" + postcode + "，详细地址：" + detail_address;
    }
}

AddressBook

package ex503.address;

import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;

public class AddressBook implements Serializable {
    private ArrayList<Address> addresses;

    public AddressBook() {
        this.addresses = new ArrayList<>();
    }

    //读取文件地址簿,文件名为“address_book.dat”,如果读取失败则创建一个新的地址簿对象
    public AddressBook readAddress(){
        ArrayList<Address> addresses = new ArrayList<>();
        try (FileInputStream fis = new FileInputStream("address_book.dat");
             ObjectInputStream ois = new ObjectInputStream(fis)){
            while (fis.available() > 0){
                Address address = (Address) ois.readObject();
                addresses.add(address);
            }
            this.addresses = addresses;
            return this;

        } catch (IOException | ClassNotFoundException e) {//读取失败或者文件不存在
            System.err.println("读取失败:"+e.getMessage());
            return new AddressBook();//创建一个新的地址簿对象
        }
    }

    //保存地址簿到文件
    public void saveAddress(){
        try(ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("address_book.dat"))){
            //oos.writeObject(this);
            for (Address address : addresses){
                oos.writeObject(address);
            }
            System.out.println("保存成功！");
        } catch (IOException e) {
            System.err.println("保存失败:"+e.getMessage());
        }
    }

    //列出所有地址
    public void showAllAddress(){
        System.out.println("序号 | 姓名 | 省份 | 城市 | 邮政编码 | 详细地址");
        System.out.println("--------------------------------------------");
        for (int i = 0; i < addresses.size(); i++){
            Address address = addresses.get(i);
            System.out.printf("%d | %s | %s | %s | %s | %s\n",i+1,address.getName(),address.getProvince(),address.getCity(),address.getPostcode(),address.getDetail_address());
        }
        System.out.println("--------------------------------------------");
        System.out.println("共["+addresses.size()+"]条数据");
    }

    //添加地址
    public void addAddress(){
        Scanner input = new Scanner(System.in);
        System.out.print("输入姓名：");
        String name = input.nextLine();
        System.out.print("输入省份：");
        String province = input.nextLine();
        System.out.print("输入城市：");
        String city = input.nextLine();
        System.out.print("输入邮政编码：");
        String postcode = input.nextLine();
        System.out.print("输入详细地址：");
        String detail_address = input.nextLine();
        Address address = new Address(name,province,city,postcode,detail_address);
        addresses.add(address);
        System.out.println("添加成功！");
    }

    //查找地址
    public void findAddress(){
        Scanner input = new Scanner(System.in);
        System.out.print("输入要查找地址的姓名：");
        String name = input.nextLine();
        System.out.println("序号 | 姓名 | 省份 | 城市 | 邮政编码 | 详细地址");
        System.out.println("--------------------------------------------");
        int i = 0;
        for (Address address : addresses){
            if(address.getName().equals(name)){
                System.out.printf("%d | %s | %s | %s | %s | %s\n",++i,address.getName(),address.getProvince(),address.getCity(),address.getPostcode(),address.getDetail_address());
            }
        }
        System.out.println("--------------------------------------------");
        System.out.println("共["+i+"]条数据");
    }

    //删除地址
    public void deleteAddress(){
        ArrayList<Address> tem_addresses = new ArrayList<>();
        Scanner input = new Scanner(System.in);
        System.out.print("输入要删除地址的姓名：");
        String name = input.nextLine();
        System.out.println("序号 | 姓名 | 省份 | 城市 | 邮政编码 | 详细地址");
        System.out.println("--------------------------------------------");
        int i = 0;
        for (Address address : addresses){
            if(address.getName().equals(name)){
                tem_addresses.add(address);
                System.out.printf("%d | %s | %s | %s | %s | %s\n",++i,address.getName(),address.getProvince(),address.getCity(),address.getPostcode(),address.getDetail_address());
            }
        }
        System.out.println("--------------------------------------------");
        System.out.println("共["+i+"]条数据");
        System.out.print("输入要删除地址的序号：");
        int index = input.nextInt();
        addresses.remove(tem_addresses.get(index-1));
    }

    //修改地址
    public void setAddresses(){
        ArrayList<Address> tem_addresses = new ArrayList<>();
        Scanner input = new Scanner(System.in);
        System.out.print("输入要修改地址的姓名：");
        String name = input.nextLine();
        System.out.println("序号 | 姓名 | 省份 | 城市 | 邮政编码 | 详细地址");
        System.out.println("--------------------------------------------");
        int i = 0;
        for (Address address : addresses){
            if(address.getName().equals(name)){
                tem_addresses.add(address);
                System.out.printf("%d | %s | %s | %s | %s | %s\n",++i,address.getName(),address.getProvince(),address.getCity(),address.getPostcode(),address.getDetail_address());
            }
        }
        System.out.println("--------------------------------------------");
        System.out.println("共["+i+"]条数据");

        System.out.print("输入选择的地址序号：");
        int index = input.nextInt();
        //消除缓冲区的回车符
        input.nextLine();
        System.out.println("姓名：");
        System.out.println("  原值："+tem_addresses.get(index-1).getName());
        System.out.print("  输入新值：");
        String new_name = input.nextLine();
        if (new_name.equals(""))new_name = tem_addresses.get(index-1).getName();

        System.out.println("省份：");
        System.out.println("  原值："+tem_addresses.get(index-1).getProvince());
        System.out.print("  输入新值：");
        String new_province = input.nextLine();
        if (new_province.equals(""))new_province = tem_addresses.get(index-1).getProvince();

        System.out.println("城市：");
        System.out.println("  原值："+tem_addresses.get(index-1).getCity());
        System.out.print("  输入新值：");
        String new_city = input.nextLine();
        if (new_city.equals(""))new_city = tem_addresses.get(index-1).getCity();

        System.out.println("邮政编码：");
        System.out.println("  原值："+tem_addresses.get(index-1).getPostcode());
        System.out.print("  输入新值：");
        String new_postcode = input.nextLine();
        if (new_postcode.equals(""))new_postcode = tem_addresses.get(index-1).getPostcode();

        System.out.println("详细地址：");
        System.out.println("  原值："+tem_addresses.get(index-1).getDetail_address());
        System.out.print("  输入新值：");
        String new_detail_address = input.nextLine();
        if (new_detail_address.equals(""))new_detail_address = tem_addresses.get(index-1).getDetail_address();

        Address address = new Address(new_name,new_province,new_city,new_postcode,new_detail_address);
        addresses.set(addresses.indexOf(tem_addresses.get(index-1)),address);
        System.out.println("修改地址成功！");
    }

    //菜单
    public void menu(){
        Scanner input = new Scanner(System.in);
        readAddress();
        while (true){
            System.out.println("---功能选项---");
            System.out.println("1.地址列表");
            System.out.println("2.查找地址");
            System.out.println("3.增加地址");
            System.out.println("4.删除地址");
            System.out.println("5.修改地址");
            System.out.println("0.退出");
            System.out.println("----------------");
            System.out.print("请输入选项号：");
            int choice = input.nextInt();
            switch (choice){
                case 1:
                    showAllAddress();
                    break;
                case 2:
                    findAddress();
                    break;
                case 3:
                    addAddress();
                    break;
                case 4:
                    deleteAddress();
                    break;
                case 5:
                    setAddresses();
                    break;
                case 0:
                    saveAddress();
                    input.close();
                    System.exit(0);
                default:
                    System.out.println("输入错误，请重新输入！");
            }
        }
    }
}

Main

package ex503;

import ex503.address.AddressBook;

public class Main{
    public static void main(String[] args) {
        AddressBook addressBook = new AddressBook();
        addressBook.menu();
    }
}