Il controllo di una linea è in un file con bufferedread e hashset
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10-12-2019 - |
Domanda
Il mio problema è che devo scrivere il codice per verificare se un nome di clienti è già nel mio file TXT (clienti.txt).
Il problema è che controllo con HasHSet se il cliente è nel file e dice che non è nel file mentre è. (controllato manualmente) Per favore aiutami a risolvere questo.
Il codice che ho già è sotto.
public class Customer {
//declaration
public static String S;
private String line ;
public String nameCustomer;
/**
* constructor
*/
public Klant(){}
/**Checking of the customer is in the file
*/
public void getCustomer() {
// make SimpleInOutDialog
SimpleInOutDialog input = new SimpleInOutDialog("Customers");
nameCustomer = input.readString("Give in the name");
try{
BufferedReader br = new BufferedReader(new FileReader("L:\\Documents/Informatica/6de jaar/GIP/Customers.txt"));
HashSet<String> hs = new HashSet<String>();
int i = 0;
while ((line = br.readLine()) != null)
{
i++;
if (i == 1){hs.add(br.readLine());}
if (i % 4 == 0){hs.add(br.readLine());}
}
if(hs.contains(nameCustomer)){
//the customer exists
input.showString("The customer exists", "");
}else{input.showString("The customer does not exist, we will make a new one", "");
setNieuweKlant();}
}catch (Exception e){//Catch when there are errors
System.err.println("Error: " + e.getMessage());}
}
/**
* make a new customer
*/
public void Make new customer(){
// make SimpleInOutDialog
SimpleInOutDialog input = new SimpleInOutDialog("A new customer");
//input
S = "Name customer: " + input.readString("Give in your name:");
WriteToFile();
S = "Adress: " + input.readString("Give your adress");
WriteToFile();
S = "Telephonenummber: " + input.readString("Give your telephonenumber");
WriteToFile();
//making a customerID
UUID idCustomer = UUID.randomUUID();
S = "CustomerID: " + customerID.toString();
WriteToFile();
}
/**
* Schrijft de gegevens weg naar het bestand
*/
public void WriteToFile(){
try{
FileWriter writer = new FileWriter("L:\\Documents/Informatica/6de jaar/GIP/Customer.txt", true);
BufferedWriter out = new BufferedWriter(writer);
//Wrting away your data
out.write(S);
//Closing the writer
out.close();
}catch (Exception e){//Catch when there are errors
System.err.println("Error: " + e.getMessage());
}
}
.
Codice olandese
.public class Klant {
//declaratie van de variabele die de tekst voorsteld
public static String S;
private String line ;
public String naamklant;
/**
* constructor
*/
public Klant(){}
/**Controleerd of de klant al bestaat
*/
public void getKlant() {
// SimpleInOutDialog aanmaken
SimpleInOutDialog input = new SimpleInOutDialog("Klanten");
naamklant = input.readString("Geef de volledige naam in");
try{
BufferedReader br = new BufferedReader(new FileReader("L:\\Documents/Informatica/6de jaar/GIP/Klanten.txt"));
HashSet<String> hs = new HashSet<String>();
int i = 0;
while ((line = br.readLine()) != null)
{
i++;
if (i == 1){hs.add(br.readLine());}
if (i % 4 == 0){hs.add(br.readLine());}
}
if(hs.contains(naamklant)){
//klant bestaat
input.showString("De klant bestaat", "");
}else{input.showString("De klant bestaat niet, er wordt een nieuwe klant aangemaakt", "");
setNieuweKlant();}
}catch (Exception e){//Catch wanneer er errors zijn
System.err.println("Error: " + e.getMessage());}
}
/**
* Maakt een nieuwe klant aan
*/
public void setNieuweKlant(){
// SimpleInOutDialog aanmaken
SimpleInOutDialog input = new SimpleInOutDialog("Een nieuwe klant");
//input
S = input.readString("Geef de volledige naam in");
WriteToFile();
S = "Adres: " + input.readString("Geef het adres op");
WriteToFile();
S = "Telefoonummer: " + input.readString("Geef het telefoonnummer op");
WriteToFile();
//een klantennummer aanmaken
UUID idKlant = UUID.randomUUID();
S = "Klantnummer: " + idKlant.toString();
WriteToFile();
}
/**
* Schrijft de gegevens weg naar het bestand
*/
public void WriteToFile(){
try{
FileWriter writer = new FileWriter("L:\\Documents/Informatica/6de jaar/GIP/Klanten.txt", true);
BufferedWriter out = new BufferedWriter(writer);
//uw gegevens wegschrijven
out.write(S);
out.newLine();
//de writer sluiten
out.close();
}catch (Exception e){//Catch wanneer er errors zijn
System.err.println("Error: " + e.getMessage());}
}
}
Soluzione
I'm really not sure what you're trying to do overall (reading every 4th line, etc.), but I wouldn't use a HashSet
if all you want is to check if a string exists in a file.
Here's a complete program for checking if a string exists in a file:
import java.io.*;
public class CheckName
{
private static boolean doesNameExistInFile(String name, String filename)
throws FileNotFoundException, IOException
{
BufferedReader reader = new BufferedReader(new FileReader(filename));
String line = null;
try {
while ((line = reader.readLine()) != null) {
if (line.equals(name))
return true;
}
} finally {
// Always close() before exiting.
reader.close();
}
return false;
}
public static void main(String[] args)
throws FileNotFoundException, IOException
{
boolean exists = doesNameExistInFile("Bender", "input.txt");
System.out.println(exists ? "Exists!" : "Does not exist.");
}
}
Contents of input file input.txt
:
Leela
Fry
Professor
Hermes
Zoidberg
A couple of things to note:
- We don't read the entire file. We stop reading once we've found the string, as that's all we're interested in.
- Always
close()
before exiting, whether string is found or not. We put the call in thefinally
block.
Altri suggerimenti
This:
while ((line = br.readLine()) != null)
{
i++;
if (i == 1){hs.add(br.readLine());}
if (i % 4 == 0){hs.add(br.readLine());}
}
is probably supposed to be this:
while ((line = br.readLine()) != null)
{
i++;
if (i == 1)
hs.add(line);
if (i % 4 == 0)
hs.add(line);
}
That is — you probably meant to add
the line that you had just read, rather than reading in a new line and add
ing it.