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我試圖從文件中讀取數據並將數據存儲到單個鏈接列表中。如何從鏈接列表中讀取文件和存儲的數據
數據有關於包括long類型的id，string類型的name，和int類型的threat level用戶的信息。此外，我想知道如何從文件中讀取並存儲到鏈接列表中，以便我可以執行多個操作。
我嘗試：
類POI
public class POI {
private long id;
private String name;
private int level;
public POI(){
}
public POI(long n, String s, int l){
id = n;
name = s;
level = l;
}
public void setID (long n){
id = n;
}
public void setName (String s){
name = s;
}
public void setLevel (int l){
level = l;
}
public long getID(){
return id;
}
public String getName(){
return name;
}
public int getLevel(){
return level;
}
}
類POIList
public class POIList {
static private class Node {
int data;
Node next;
Node() {
data = 0;
next = null;
}
Node(int data, Node next) {
this.data = data;
this.next = next;
}
}
public static void print(Node head) {
while (head != null) {
System.out.print(head.data + ", ");
head = head.next;
}
System.out.println();
}
public Node insertNode(Node head, Node insertee, int position) {
if (position < 0) {
System.out.println("Invalid position given");
return head;
}
if (head == null) {
return insertee;
}
if (position == 0) {
insertee.next = head;
return insertee;
}
int i = 0;
Node current=head;
while (i < position - 1 && current.next != null) {
current = current.next;
i++;
}
if (i == position - 1) {
insertee.next = current.next;
current.next = insertee;
} else {
System.out.println("Position was not found.");
}
return head;
}
static Node swapNode(Node head,
int position1, int position2) {
if(position1 < 0 || position2 < 0)
System.out.println("InvalidPos");
Node n1 = null;
Node n2 = null;
Node prev1=null;
Node prev2=null;
int maxPosition = Math.max(position1, position2);
if (position1==maxPosition){
position1=position2;
position2=maxPosition;
}
Node temp=head;
for (int i = 0;i <= maxPosition; i++) {
if (temp == null) {
System.out.println("InvalidPos");
return head;
}
if (i==position1-1) prev1=temp;
if(i == position1) n1 = temp;
if (i==position2-1) prev2=temp;
if(i == position2) n2 = temp;
temp = temp.next;
}
temp = n2.next;
if (prev1!=null){
prev1.next=n2;
}else{
head=n2;
}
if (position2-position1==1){
n2.next=n1;
}else{
n2.next=n1.next;
}
if (prev2!=null){
prev2.next=n1;
}else{
head=n1;
}
n1.next=temp;
return head;
} // End of swapNode
public static Node removeNode(Node head, int position) {
if (position < 0 || head == null) {
System.out.println("Invalid position given");
return head;
}
if (position == 0) {
return head.next;
}
int i = 0;
Node current = head;
while (i < position - 1 && current.next != null) {
current = current.next;
i++;
}
if (current.next != null) {
current.next = current.next.next;
} else {
System.out.println("Position was not found.");
}
return head;
}
}
類AnalyzePOI
public class AnalyzePOI {
public static void main (String [] args) throws FileNotFoundException, IOException{
Scanner scan = new Scanner(System.in);
int choice;
System.out.print("Input filename:");
String filename = scan.nextLine();
File file = new File(filename);
Scanner reader = new Scanner(file);
POIList list = new POIList();
System.out.println("What operation would you like to implement? ");
choice = scan.nextInt();
switch (choice) {
case 1 : print(list) ;
break ;
case 2 : search(reader, list) ;
break ;
case 3 : insert(scan, list);
break ;
case 4 : swap(reader, list);
break ;
case 5 : remove1(reader, list);
break;
case 6 : remove2(reader, list);
break;
case 7 : output();
break;
case 8 :
System.out.println ("Program Terminated");
System.exit(0);
break;
}
start(scan,file, reader);
}
public static void start (Scanner scan, File file, Scanner reader){
String content = new String();
int count=1;
File file1 = new File("abc.txt");
LinkedList<String> list = new LinkedList<String>();
try {
Scanner sc = new Scanner(new FileInputStream(file));
while (sc.hasNextLine()){
content = sc.nextLine();
list.add(content);
}
sc.close();
}catch(FileNotFoundException fnf){
fnf.printStackTrace();
}
catch (Exception e) {
e.printStackTrace();
System.out.println("\nProgram terminated Safely...");
}
Collections.reverse(list);
Iterator i = (Iterator) list.iterator();
while (((java.util.Iterator<String>) i).hasNext()) {
System.out.print("Node " + (count++) + " : ");
System.out.println();
}
}
public static void print(POIList list) {
list.print(null);
}
public static void search(Scanner scan, POIList list) {
int id;
String name;
System.out.println("Do you want to enter id or name to search for record: ");
String answer = scan.next();
if (answer == "id"){
System.out.println ("Enter the id to find the record: ");
id = scan.nextInt();
}
else if (answer == "name"){
System.out.println("Enter the name to find the record: ");
name = scan.nextLine();
}
else{
System.out.println("Invalid input");
}
}
public static void insert(Scanner scan, POIList list) {
System.out.println("Enter the the location index ");
int index = 0;
long p1;
int level;
String name;
try {
System.out.println("Index: ") ;
index= scan.nextInt() ;
System.out.println("ID: ") ;
p1=scan.nextLong() ;
System.out.println("Name: ");
name = scan.nextLine();
System.out.println("Threat Level ") ;
level=scan.nextInt() ;
}
catch (InputMismatchException e) {
System.out.print("Invalid Input") ;
}
list.insertNode(null, null, index);
}
public static void swap(Scanner scan, POIList list) {
System.out.println("Enter index 1 to swap record: ");
int index1 = scan.nextInt();
System.out.println("Enter index 2 to swap record: ");
int index2 = scan.nextInt();
list.swapNode(null, index1, index2);
}
public static void remove1(Scanner scan, POIList list) {
int index= 0;
try{
System.out.println("Enter ID to remove a record: ") ;
index=scan.nextInt() ;
}
catch (InputMismatchException e) {
System.out.print("Invalid Input") ;
}
list.removeNode(null, index) ;
}
public static void remove2(Scanner scan, POIList list){
int index = 0;
try{
System.out.println("Enter threat level to remove a record: ");
index=scan.nextInt() ;
}
catch (InputMismatchException e){
System.out.println("Invalid Input");
}
list.removeNode(null, index) ;
}
public static void output() {
}
}
我不確定你是問。你的方法不工作？或者您是否要求提供更多建議以改進此過程 – ShankarDaruga
是的，稱爲啓動的方法無效。我不知道如何讀取文件並將其傳遞給鏈表。該文件包含一個長整型，一個字符串和一個整數，但我不知道如何存儲這些數據類型並將它們傳遞給鏈表。 – Alan
嗯。好的。在下面檢查我的答案。但是，在此之前，我認爲除了start方法外，其他代碼部分還存在一些問題。我沒有經歷全部。但是，你不覺得POIList類應該有POI，接下來是Node類而不是int和next嗎？你在哪裏使用POI課程進行存儲？ – ShankarDaruga