操作系统文件系统模拟-创新互联
操作系统简单文件系统模拟(Java和C++)：
结果展示：
分享题目：操作系统文件系统模拟-创新互联
当前地址：http://hbruida.cn/article/ddscsd.html
没有持久化存储到本地系统盘，演示结果：使用Java语言实现，附带C++版本
主要的两个类：文件夹和文件
class FOLDER{//目录结构
String name=new String();//目录名
FOLDER nextFolder;//同级下一目录
FOLDER frontFolder;//同级上一目录
FOLDER parentFolder;//父目录
FOLDER firstChildFolder;//子目录
FOLDER lastChildFolder;//最后一个子文件夹
FILE firstChildFile;//子文件
FILE lastChildFile;
public FOLDER(String name, FOLDER nextFolder, FOLDER frontFolder, FOLDER parentFolder, FOLDER firstChildFolder, FOLDER lastChildFolder, FILE firstChildFile, FILE lastChildFile)
{this.name = name;
this.nextFolder = nextFolder;
this.frontFolder = frontFolder;
this.parentFolder = parentFolder;
this.firstChildFolder = firstChildFolder;
this.lastChildFolder = lastChildFolder;
this.firstChildFile = firstChildFile;
this.lastChildFile = lastChildFile;
}
public FOLDER() {}
}
class FILE{String name=new String();//文件名
String content=new String();//文件内容
FILE frontFile;//同级目录上一文件
FILE nextFile;//同级目录下一文件
FOLDER parentFolder;//父目录
public FILE(String name, String content, FILE frontFile, FILE nextFile, FOLDER parentFolder) {this.name = name;
this.content = content;
this.frontFile = frontFile;
this.nextFile = nextFile;
this.parentFolder = parentFolder;
}
public FILE() {}
}解释：有一个总的root文件夹，每一个文件夹类，采用类似链表的连接方式，记录当前目录下的第一个文件夹和最后一个文件夹，可以遍历查找，而文件也是同样的方式。
代码实现实现的Java代码：
import java.util.Objects;
import java.util.Scanner;
public class FileSystem {
FOLDER root,nowpath;
public static void main(String[] args) {
FileSystem init = new FileSystem();
init.createRoot();
init.menu();
}
// 切换目录
void open_dir(String name) {
// 返回上一层目录
if(Objects.equals(name, "../")){
if(nowpath!=root)
nowpath = nowpath.parentFolder;
return;
}
FOLDER a = nowpath.firstChildFolder;
while(a!=null && !Objects.equals(a.name, name))
a = a.nextFolder;
if(a==null || !Objects.equals(a.name, name)){
System.out.println("没有找到"+name);
return;
}
nowpath = a;
}
// 展示目录
void showInfo() {
FOLDER x = nowpath.firstChildFolder;
while(x!=null){
System.out.println(x.name);
x = x.nextFolder;
}
FILE y = nowpath.firstChildFile;
while (y!=null){
System.out.println(y.name);
y = y.nextFile;
}
}
// 修改文件
void modify(String name) {
FILE a = nowpath.firstChildFile;
FILE b = nowpath.lastChildFile;
while (a!=null && !Objects.equals(a.name, name))
a = a.nextFile;
if(a==null || !Objects.equals(a.name, name)){
System.out.println("没有找到"+name);
return;
}
System.out.print("选择续写: 1\n覆盖写入: 2\n");
Scanner in = new Scanner(System.in);
int op = in.nextInt();
if(op==2) a.content = "";
System.out.println("输入内容");
in.nextLine(); //吞掉换行符
String s = in.nextLine();
System.out.println(s+"-------检测输入");
if(a.content!=null) a.content = a.content+s;
else a.content = s;
}
// 查看文件内容
void show_context(String name) {
FILE a = nowpath.firstChildFile;
while(a!=null && !Objects.equals(a.name, name))
a = a.nextFile;
if(a==null || !Objects.equals(a.name, name)){
System.out.println("没有找到"+name+"文件");
return;
}
else System.out.println(a.content);
}
// 删除文件
void rm(String name) {
boolean flag = false;
FILE a = nowpath.firstChildFile;
FILE b = nowpath.lastChildFile;
if(a==null){
if (flag) System.out.println("成功删除");
else System.out.println("不存在"+name+"文件");
return;
}
// 第一个文件就是要找的文件
if(a!=null && Objects.equals(a.name, name)){
flag = true;
boolean fl = a == b ? true : false;
FILE nxt = a.nextFile;//是否还有其他文件
nowpath.firstChildFile = nxt;
if (nxt != null)
nxt.frontFile = null;
if (fl)
nowpath.lastChildFile = null;
}
else if(b!=null && Objects.equals(b.name, name)){
flag = true;
FILE pre = b.frontFile;
nowpath.lastChildFile = pre;
if(pre!=null)
pre.nextFile = null;
}
else { // 不是第一个和最后一个文件，从头遍历查找此文件
if(a.nextFile!=null) a = a.nextFile;
while (a!=null && a!=b && !Objects.equals(a.name, name))
a = a.nextFile;
if (a != null && Objects.equals(a.name, name))
{
flag = true;
FILE pre = a.frontFile;
FILE nxt = a.nextFile;
if (pre != null)
pre.nextFile = nxt;
if (nxt != null)
nxt.frontFile = pre;
}
}
if (flag) System.out.println("成功删除");
else System.out.println("不存在"+name+"文件");
}
// 创建文件
void touch_file(String name) {
FILE x = nowpath.firstChildFile;
FILE y = nowpath.lastChildFile;
boolean flag = true;
while (x!=y){
if(Objects.equals(x.name, name))
flag = false;
x = x.nextFile;
}
if(y!=null && Objects.equals(y.name, name))
flag = false;
if(!flag){
System.out.println("当前文件名已存在");
return;
}
FILE newFile = new FILE(name,null,null,null,nowpath);
if (nowpath.firstChildFile == null){
nowpath.firstChildFile = newFile;
nowpath.lastChildFile = newFile;
}
else
{
FILE b = nowpath.lastChildFile;
b.nextFile = newFile;
newFile.frontFile = b;
nowpath.lastChildFile = newFile;
}
}
void del(FOLDER a){
if (a == null) return;
FILE x = a.firstChildFile;
FILE y = a.lastChildFile;
while (x != y)
{
FILE t = x.nextFile;
x = t;
}
FOLDER xF = a.firstChildFolder;
FOLDER yF = a.lastChildFolder;
while (xF != yF)
{
FOLDER t = xF.nextFolder;
del(xF);
xF = t;
}
if (yF != null)
{
del(yF);
}
}
// 删除文件夹
void remove_directory(String name) {
boolean flag = false;
FOLDER a = nowpath.firstChildFolder;
FOLDER b = nowpath.lastChildFolder;
if(a==null){
if(flag) System.out.println("成功删除");
else System.out.println("没有"+name+"文件夹");
return;
}
if(a!=null && Objects.equals(a.name, name)){
flag = true;
boolean f1 = b == a ? true : false;
FOLDER nxt = a.nextFolder;
del(a);
nowpath.firstChildFolder = nxt;
if (nxt != null)
nxt.frontFolder = null;
if (flag) //同时又是最后一个
nowpath.lastChildFolder = null;
}
else if(b!=null && Objects.equals(b.name, name)){
flag = true;
FOLDER pre = b.frontFolder;
del(pre);
nowpath.lastChildFolder = pre;
if (pre != null)
pre.nextFolder = null;
}
else {
a = a.nextFolder;
// 递归删除
while (a != null && a != b && !Objects.equals(a.name, name))
a = a.nextFolder;
// 删除最后的文件夹
if (a != null && Objects.equals(a.name, name))
{
flag = true;
FOLDER pre = a.frontFolder;
FOLDER nxt = a.nextFolder;
del(a);
if (pre != null)
pre.nextFolder = nxt;
if (nxt != null)
nxt.frontFolder = pre;
}
}
if(flag) System.out.println("成功删除");
else System.out.println("没有"+name+"文件夹");
}
// 添加文件夹
void make_directory(String name)
{
FOLDER x = nowpath.firstChildFolder;
FOLDER y = nowpath.lastChildFolder;
boolean flag = true;
// 是否有同名的子目录,有同名不让创建
while (x != y)
{
if (Objects.equals(x.name, name)) flag = false;
x = x.nextFolder;
}
if (y != null && Objects.equals(y.name, name))
flag = false;
if(!flag)
{
System.out.println(name + "文件夹已存在");
return;
}
// 无同名文件夹，开始创建文件夹
FOLDER newFolder = new FOLDER(name,null,null,
nowpath,null,null,null,null);
if(nowpath.firstChildFolder==null){
nowpath.firstChildFolder = newFolder;
nowpath.lastChildFolder = newFolder;
}
else
{
// 更新当前文件夹下的第一个子文件夹和最后一个子文件夹 (链表的形式)
FOLDER tmp = nowpath.lastChildFolder;
tmp.nextFolder = newFolder;
newFolder.frontFolder = tmp;
nowpath.lastChildFolder = newFolder;
}
}
String getPath()
{
String path = nowpath.name+">";
FOLDER now = nowpath;
while(now.parentFolder!=null)
{
now = now.parentFolder;
path = now.name +"/"+path;
}
return path;
}
void Operation(String op,String name)
{
if(Objects.equals(op, "exit")){
System.out.println("操作结束!!!");
System.exit(0);
}
if(Objects.equals(op, "mkdir")) make_directory(name);
else if(Objects.equals(op, "rmdir")) remove_directory(name);
else if(Objects.equals(op, "touch")) touch_file(name);
else if(Objects.equals(op, "rm")) rm(name);
else if(Objects.equals(op, "cat")) show_context(name);
else if(Objects.equals(op, "vim")) modify(name);
else if(Objects.equals(op, "ls")) showInfo();
else if(Objects.equals(op, "cd")) open_dir(name);
else System.out.println(op + "命令没找到");
}
void menu()
{
Scanner in = new Scanner(System.in);
System.out.println(" 创建目录 -- mkdir\n" +
" 删除目录 -- rmdir\n" +
" 切换目录 -- cd\n" +
" 创建文件 -- touch\n" +
" 删除文件 -- rm\n" +
" 查看文件内容 -- cat\n" +
" 写入文件 -- vim\n" +
" 查看目录 -- ls\n" +
" 退出系统 -- exit");
while(true)
{
System.out.print(getPath());
String ss = in.nextLine();
String[] s = ss.split(" ");
if(s.length>2) System.out.println("输入有误");
String op = new String();
String name = new String();
op = s[0];
if(s.length==2 )name = s[1];
Operation(op,name);
}
}
void createRoot() {//初始化根目录信息
root=new FOLDER();
root.frontFolder=null;
root.nextFolder=null;
root.parentFolder=null;
root.firstChildFile=null;
root.firstChildFolder=null;;
root.lastChildFile = null;
root.name="root";
nowpath = root;
}
}
class FOLDER{//目录结构
String name=new String();//目录名
FOLDER nextFolder;//同级下一目录
FOLDER frontFolder;//同级上一目录
FOLDER parentFolder;//父目录
FOLDER firstChildFolder;//子目录
FOLDER lastChildFolder;//最后一个子文件夹
FILE firstChildFile;//子文件
FILE lastChildFile;
public FOLDER(String name, FOLDER nextFolder, FOLDER frontFolder, FOLDER parentFolder, FOLDER firstChildFolder, FOLDER lastChildFolder, FILE firstChildFile, FILE lastChildFile)
{
this.name = name;
this.nextFolder = nextFolder;
this.frontFolder = frontFolder;
this.parentFolder = parentFolder;
this.firstChildFolder = firstChildFolder;
this.lastChildFolder = lastChildFolder;
this.firstChildFile = firstChildFile;
this.lastChildFile = lastChildFile;
}
public FOLDER() {}
}
class FILE{
String name=new String();//文件名
String content=new String();//文件内容
FILE frontFile;//同级目录上一文件
FILE nextFile;//同级目录下一文件
FOLDER parentFolder;//父目录
public FILE(String name, String content, FILE frontFile, FILE nextFile, FOLDER parentFolder) {
this.name = name;
this.content = content;
this.frontFile = frontFile;
this.nextFile = nextFile;
this.parentFolder = parentFolder;
}
public FILE() {}
}
C++版本：
#includeusing namespace std;
struct Folder;
struct File
{
string name;
string context;
int canRead;
int canWrite;
File* frontFile;
File* nextFile;
Folder* parent;
};
struct Folder
{
string name;
int canRead;
int canWrite;
Folder* nextFolder;
Folder* frontFolder;
Folder* parent;
Folder* firstChildFolder;
Folder* lastChildFolder;
File* firstChildFile;
File* lastChildFile;
};
Folder* nowpath,* root;
void createroot()
{
root = new Folder{
name : "root",
canRead : 1,
canWrite : 0,
nextFolder : nullptr,
frontFolder : nullptr,
parent : nullptr,
firstChildFolder : nullptr,
firstChildFile : nullptr,
lastChildFile : nullptr
};
nowpath = root;
}
string getpath() //获取当前文件夹路径
{
string path = nowpath->name + ">";
Folder *now = nowpath;
while (now ->parent != nullptr)
{
now = now->parent;
path = now->name + "/" + path;
}
return path;
}
void make_directory(string name) //创建目录
{
auto x = nowpath->firstChildFolder;
auto y = nowpath->lastChildFolder;
bool flag = true;
while (x != y)
{
if (x->name == name)
flag = false;
x = x->nextFolder;
}
if (y != nullptr && y->name == name)
flag = false;
if (!flag)
{
cout<< "cannot create directory '" + name + "': Directory exists\n";
return;
}
Folder *newFolder = new Folder{
name : name,
canRead : 1,
canWrite : 0,
nextFolder : nullptr,
frontFolder : nullptr,
parent : nowpath,
firstChildFolder : nullptr,
lastChildFolder : nullptr,
firstChildFile : nullptr,
lastChildFile : nullptr
};
if (nowpath->firstChildFolder == nullptr)
nowpath->firstChildFolder = nowpath->lastChildFolder = newFolder;
else
{
auto b = nowpath->lastChildFolder;
b->nextFolder = newFolder;
newFolder->frontFolder = b;
nowpath->lastChildFolder = newFolder;
}
}
void del(Folder *a) //递归删除a的所有子文件
{
if (a == nullptr) return;
auto x = a->firstChildFile;
auto y = a->lastChildFile;
while (x != y)
{
auto t = x->nextFile;
free(x);
x = t;
}
if (y != nullptr)
free(y);
auto xF = a->firstChildFolder;
auto yF = a->lastChildFolder;
while (xF != yF)
{
auto t = xF->nextFolder;
del(xF);
free(xF);
xF = t;
}
if (yF != nullptr)
{
del(yF);
free(yF);
}
}
void remove_directory(string name)
{
bool flag = false;
auto a = nowpath->firstChildFolder;
auto b = nowpath->lastChildFolder;
if (a == nullptr) goto cc;
if (a != nullptr && a->name == name)
{
flag = true;
bool fl = b == a ? true : false;
auto nxt = a->nextFolder;
del(a);
free(a);
nowpath->firstChildFolder = nxt;
if (nxt != nullptr)
nxt->frontFolder = nullptr;
if (flag) //同时又是最后一个
nowpath->lastChildFolder = nullptr;
}
else if (b != nullptr && b->name == name)
{
flag = true;
auto pre = b->frontFolder;
del(b);
free(b);
nowpath->lastChildFolder = pre;
if (pre != nullptr)
pre->nextFolder = nullptr;
}
else
{
a = a->nextFolder;
while (a != nullptr && a != b && a->name != name)
a = a->nextFolder;
if (a != nullptr && a->name == name)
{
flag = true;
auto pre = a->frontFolder;
auto nxt = a->nextFolder;
del(a);
free(a);
if (pre != nullptr)
pre->nextFolder = nxt;
if (nxt != nullptr)
nxt->frontFolder = pre;
}
}
cc: if (flag)
cout<< "OK\n";
else cout<< "failed to remove '" + name + "' No such directory\n";
}
void touch_file(string name)
{
auto x = nowpath->firstChildFile;
auto y = nowpath->lastChildFile;
bool flag = true;
while (x != y)
{
if (x->name == name)
flag = false;
x = x->nextFile;
}
if (y != nullptr && y->name == name)
flag = false;
if (!flag)
{
cout<< "cannot create directory '" + name + "': File exists\n";
return;
}
File * newfile = new File{
name : name,
canRead : 1,
canWrite : 1,
frontFile : nullptr,
nextFile : nullptr,
parent : nowpath
};
if (nowpath->firstChildFile == nullptr)
nowpath->firstChildFile = nowpath->lastChildFile = newfile;
else
{
auto b = nowpath->lastChildFile;
b->nextFile = newfile;
newfile->frontFile = b;
nowpath->lastChildFile = newfile;
}
}
void rm(string name)
{
bool flag = false;
auto a = nowpath->firstChildFile;
auto b = nowpath->lastChildFile;
if (a == nullptr) goto cc;
if (a != nullptr && a->name == name)
{
flag = true;
bool fl = a == b ? true : false;
auto nxt = a->nextFile;
free(a);
nowpath->firstChildFile = nxt;
if (nxt != nullptr)
nxt->frontFile = nullptr;
if (fl)
nowpath->lastChildFile = nullptr;
}
else if (b != nullptr && b->name == name)
{
flag = true;
auto pre = b->frontFile;
free(b);
nowpath->lastChildFile = pre;
if (pre != nullptr)
pre->nextFile = nullptr;
}
else
{
a = a->nextFile;
while (a != nullptr && a != b && a->name != name)
a = a->nextFile;
if (a != nullptr && a->name == name)
{
flag = true;
auto pre = a->frontFile;
auto nxt = a->nextFile;
free(a);
if (pre != nullptr)
pre->nextFile = nxt;
if (nxt != nullptr)
nxt->frontFile = pre;
}
}
cc: if (flag)
cout<< "OK\n";
else cout<< "failed to remove '" + name + "' No such file\n";
}
void show_context(string name)
{
auto a = nowpath->firstChildFile;
auto b = nowpath->lastChildFile;
while (a != nullptr && a->name != name)
a = a->nextFile;
if (a == nullptr || a->name != name)
{
cout<< "No such file or directory\n";
return;
}
else cout<< a->context<< '\n';
}
void modify(string name)
{
auto a = nowpath->firstChildFile;
auto b = nowpath->lastChildFile;
while (a != nullptr && a->name != name)
a = a->nextFile;
if (a == nullptr || a->name != name)
{
cout<< "No such file or directory\n";
return;
}
cout<< "续写 -r\n覆盖 -w\n";
string op;
cin >>op;
if (op == "-w")
a->context = "";
cout<< "请输入内容\n";
getchar();
getline(cin,op);
a->context += op;
}
void show()
{
auto x = nowpath->firstChildFile;
while (x != nullptr)
{
cout<< x->name<< '\n';
x = x->nextFile;
}
auto xF = nowpath->firstChildFolder;
while (xF != nullptr)
{
cout<< xF->name<< '\n';
xF = xF->nextFolder;
}
}
void open_dir(string name)
{
if (name == "..")
{
if (nowpath != root)
nowpath = nowpath->parent;
return;
}
auto a = nowpath->firstChildFolder;
auto b = nowpath->lastChildFolder;
while (a != nullptr && a->name != name)
a = a->nextFolder;
if (a == nullptr || a->name != name)
{
cout<< "No such file or directory\n";
return;
}
nowpath = a;
}
void Operation(string op,string name)
{
if (op == "exit")
{
cout<< "bye\n";
exit(0);
}
if (op == "mkdir")
make_directory(name);
else if (op == "rmdir")
remove_directory(name);
else if (op == "touch")
touch_file(name);
else if (op == "rm")
rm(name);
else if (op == "cat")
show_context(name);
else if (op == "vim")
modify(name);
else if (op == "ls")
show();
else if (op == "cd")
open_dir(name);
else cout<< op + " : command not found\n";
}
int main()
{
createroot();
cout<< "创建目录 -- mkdir\n\
删除目录 -- rmdir\n\
打开目录 -- cd\n\
创建文件 -- touch\n\
删除文件 -- rm\n\
查看文件 -- cat\n\
写入文件 -- vim\n\
列出目录 -- ls\n\
退出系统 -- exit\n";
while (1)
{
cout<< getpath();
string s,op,name;
getline(cin,s);
stringstream ss(s);
ss >>op >>name;
Operation(op,name);
}
return 0;
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分享题目：操作系统文件系统模拟-创新互联
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