Java implementation reads the student information from the file and implements the deletion and modification

Implement one-way linked list and realize IO first

Package SAVE;
	public class Linklist {//Linked list public Node-I;

	private int pos;
	Public linklist () {This.first = new Node (null);
		}/** * * @param stu/public void AddNode (Student stu) {node node = new node (stu);
		Node current = i;
		while (current.next!= null) {current = Current.next;
		} Node.next=current.next;
		
	Current.next = node;
		//delete node public void Deletenode (String num) {node current = i; if (First.next!= null) {while (!current.next.stu.snum.equals (num) && (current.next!= null)) {current =
			Current.next;
			} if (Current.next.stu.Snum.equals (num)) {current.next = Current.next.next;
			else {System.out.println ("there is no such student information in the system");
		} else {System.out.println ("There is no storage content in the system currently");
		}///Search node public node selectnode (String num) {node current = i; if (First.next!= null) {while (!current.next.stu.snum.equals (num) && (current.next!= null)) {current =
			Current.next;
	}		if (current.next.stu.Snum.equals (num)) {//current.next = Current.next.next;
			return current.next;
			else {System.out.println ("there is no such student information in the system");
		} else {System.out.println ("There is no storage content in the system currently");
	return null;
		Public boolean select (String num) {Node current = i; if (First.next!= null) {while (current.next.next!= null) &&!current.next.stu.snum.equals (num)) {Curren
			t = Current.next;
				} if (Current.next.stu.Snum.equals (num)) {//current.next = Current.next.next;
			return true;
			else {System.out.println ("there is no such student information in the system");
		} else {System.out.println ("There is no storage content in the system currently");
	return false;
 }

}

Package SAVE;
Import java.io.*;

Import java.util.*;
	Class Student {public String Name;
	Public String Snum;

	Public String School;
		Public Student () {} public Student (string name, String snum, string school) {name = name;
		Snum = Snum;
	School = School;
	} class Node {//Node public node next;
	Student Stu;
	Public Node (Student stu) {this.stu = Stu;  The public class Save {/** * Write method * @param str * @throws ioexception//*public static void Write (String
		STR, Boolean applent) throws IOException {String fileName = "C:" + file.separator + "Student.txt";
		File File = new file (fileName);
		OutputStream out = new FileOutputStream (file, applent);
		STR + + "r";
		Byte[] B = str.getbytes ();
		try {file.createnewfile ();
		catch (Exception e) {e.printstacktrace ();
	} out.close (); }*/public static void Write (String Str,boolean p) throws IOException {string fileName = "D:" + file.separator + "stud"
		Ent.txt "; File File = new file (FilenaME);	
		OutputStream out = new FileOutputStream (file, true);
		String str= "DSF";
		String deststr = new string ();  
        Deststr =str;  
        FileWriter FW = new FileWriter ("D://student.txt", p);  
        PrintWriter pw = new PrintWriter (FW);  
        
		Pw.println (DESTSTR);
		Byte[] B = str.getbytes ();
		try {file.createnewfile ();
		catch (Exception e) {e.printstacktrace ();
		}//out.close ();  
        Pw.close (); 
	Fw.close (); /** * Read Method * * @return * @throws ioexception/public static void Read (Linklist list) throws Ioexcepti
		
		On {InputStream is = new FileInputStream ("D://student.txt"); String str=new () string line;
		Used to hold content read per row Student stu= new Student ();
		BufferedReader reader = new BufferedReader (new InputStreamReader (IS)); line = Reader.readline ();
		Reads the first row if (line = = null) System.out.println ("File is empty"); while (Line!=null&&line.length () >=2) {//If line is empty description read//line+= "\ n";//Add newline character Stu = TranSformtostudent (line);
			List.addnode (Stu);
			System.out.println (line); line = Reader.readline ();
		Read Next line} reader.close ();
	Is.close (); /** * Converts string to Student class plus * * @param str * @param list/public static Student transformtostudent (String str
		) {Student stu;
		string[] Str1 = Str.split (",");
			if (str1.length!= 3) {System.out.println ("wrong Information");
		return null;
			else {stu = new Student (str1[1], str1[0], str1[2]);
		return Stu;
		The public static void Printstudent (Linklist link) throws IOException {Node n = link.first.next;
		String S = new string ();
			while (n!= null) {//system.out.println (N.stu.snum + "," + N.stu.name + "," + N.stu.school);
			S + + N.stu.snum + "," + N.stu.name + "," + N.stu.school + "\ r \ n";
		n = n.next;
		Write (S, false);
	System.out.println (S); }/** * * @param args * @throws ioexception/public static void main (string[] args) throws IOException {L
		Inklist list = new linklist (); Student stu = New Student ();
		File File = new file ("D:" + file.separator + "Student.txt");
		Read (list);
		String str = new string ();
		/*if (str.length () = 0) System.out.println ("File is empty");
			
			else {string[] line = str.split ("\ n");
				Converts the string to the student class and joins the list for (int i = 0; i < line.length; i++) {stu = Transformtostudent (Line[i]);
			List.addnode (Stu);
		}}*///Scanner in = new Scanner (system.in);
		String help = "Please enter a key value number for the corresponding function: 1. Increase the student information in the System 2. Delete the student information in the system" + "3. Revise student Information 4. Find student information 0. Exit";
		System.out.println (Help);
		int key = In.nextint ();
			while (key!= 0) {//system.out.println (Help);
					Switch (key) {//Add Case 1: {//do {System.out.println ("Please enter student information, order for school number, name, schools");
					str = In.next ();
					Student STU1 = transformtostudent (str); if (List.select (STU1).
					Snum)) {System.out.println ("The school number is already in the system, do not repeat input");
						} else{List.addnode (STU1);
						String S = new string (); S = stu1. Snum + "," + STU1. Name + "," + STU1. School;
					}//write (S, true);
					Printstudent (list);
					System.out.println (Help);
				Key = In.nextint ();

				while (key = = 5);
			Break
					//Delete Case 2: {//do {System.out.println ("Please enter the school number");
					str = In.next ();
					List.deletenode (str);
					Printstudent (list);
					System.out.println (Help);
				Key = In.nextint ();

				while (key = = 5);
			Break
					//Change Case 3: {//do {System.out.println ("Please enter the school number");
					str = In.next ();
					Student s2 = list.selectnode (str). Stu;
					System.out.println ("Please enter the revised information in order: Name, school");
					str = In.next ();
					string[] Arr = Str.split (","); S2.
					Name = arr[0]; S2.
					School = arr[1];
					Printstudent (list);
					System.out.println (Help);
				Key = In.nextint ();

				while (key = = 5);
			Break
					//Check Case 4: {//do {System.out.println ("Please enter the school number");
					String STR4 = In.next ();
					Student s2 = List.selectnode (STR4). Stu; String ste = S2. snum+ "," +s2. Name+ "," +s2.
School;					System.out.println ("School Number:" + s2.)
					Snum); System.out.println ("Name:" + s2.)
					Name); System.out.println ("School:" + s2.)
					School);
					System.out.println (Help);
				Key = In.nextint ();
				while (key = = 5);
			Break
				}/*default:system.out.println (Help); break;*/}}}