Java 实现简单Shell 的demo

package package1;
import java.io.*;
import java.lang.invoke.SwitchPoint;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Echo{
    public void duty(String s){
        System.out.println(s);
    }
}

class Grep{
    public void duty(String pattern,String path) throws IOException {
        FileReader reader=new FileReader(path);
        BufferedReader bufReader=new BufferedReader(reader);

        String s=null;
        while ((s=bufReader.readLine())!=null){
            Matcher m=Pattern.compile(pattern).matcher(s);
            if(m.find()){
                System.out.println(s);
            }
        }
    }
}

class Pwd{
    public void duty(String path){
        File f=new File(path);
        System.out.println(f.getAbsoluteFile());
    }
}


class Ls{
    public void duty(File f){
        String[] arr=f.list();
        int i=0;
        while (i<arr.length){
            System.out.println(arr[i]);
            i++;
        }
    }
}

class Cd{
    public File duty(File srcPath,String dstPath){
        File f=new File(dstPath);
        if(!f.exists()){
            System.out.println("No such file or directory");
            return srcPath;
        }else{
            return  f;
        }
    }
}

class Cat{
    public void duty(File path,String name) throws IOException {
        File f=new File(path,name);
        if (!f.exists()){
            System.out.println("no such file");
        }
        BufferedReader bufReader=new BufferedReader(new FileReader(f));
        String s=null;
        while ((s=bufReader.readLine())!=null){
            System.out.println(s);
        }
    }
}

class Mkdir{
    public void duty(File path,String name){
        File f=new File(path,name);
        f.mkdirs();
    }
}

class Cp{
    public void duty(String src,String dst) throws IOException {
        FileInputStream fsrc=new FileInputStream(src);
        byte[] arr=new byte[fsrc.available()];
        fsrc.read(arr);
        fsrc.close();

        File fdst=new File(dst);
        if (!fdst.exists()){
            fdst.createNewFile();
        }

        FileOutputStream fds=new FileOutputStream(fdst);
        fds.write(arr);
        fds.close();
    }
}
public class Shell {
    public static String pathname;
    public static void main(String[] args) throws IOException {
        System.out.println("请输入你想选择的当前路径(例如 C:/User/wyh17):");
        Scanner scanner=new Scanner(System.in);
        pathname=scanner.nextLine();
        File f=new File(pathname);
        if (!f.exists()){
            f.mkdirs();
        }
        System.out.print("wyh@FX:"+f.getAbsolutePath()+"$");
        String str1;
        String[] arr;
        while (true){
            str1=scanner.nextLine();
            arr=str1.split(" ");
            switch (arr[0]){
                case "echo":
                    Echo echo=new Echo();
                    if (arr.length>2){
                        Grep grep=new Grep();
                        grep.duty(arr[1],arr[4]);
                    }else {
                        echo.duty(arr[1]);
                    }
                    break;
                case  "grep":
                    Grep grep=new Grep();
                    grep.duty(arr[1],arr[2]);
                    break;
                case "ls":
                    Ls ls=new Ls();
                    ls.duty(f);
                    break;
                case "pwd":
                    Pwd pwd=new Pwd();
                    pwd.duty(pathname);
                    break;
                case "cd":
                    Cd cd=new Cd();
                    f=cd.duty(f,arr[1]);
                    break;
                case "cat":
                    Cat cat=new Cat();
                    cat.duty(f,arr[1]);
                    break;
                case "mkdir":
                    Mkdir mkdir=new Mkdir();
                    mkdir.duty(f,arr[1]);
                    break;
                case "cp":
                    Cp cp=new Cp();
                    cp.duty(arr[1],arr[2]);
                    break;
                case "exit":
                    System.exit(0);
                default:
                    System.out.println("no such command");
            }
            System.out.print("wyh@FX:"+f.getAbsolutePath()+"$");

        }
    }
}

来源：CSDN

作者：飔下独角兽

链接：https://blog.csdn.net/weixin_44625793/article/details/104171037