Checking if a customers name is already in a txt file with FileReader

问题

My problem is that I have to write code to check if a customers name is already in my txt file (Customers.txt).

As you can see, I write my customers name ,every fourth line in my txt File. I would like to have the input of a customers name with SimpleInOutDialog en then that inputs needs to be compared with al the customers name in my txt file. How do I need to do this?

The code that I already have is below.

//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/klanten.txt"));
HashSet<String> hs = new HashSet<String>();
int i = 0;
while ((line = br.readLine()) != null)
{
    i++;

       if (i % 4 == 0){
          if(hs.contains(namecustomer)){
             //customer exists
          input.showString("The customer exists", "");}
          else
           {setNewcustomer();}}


}
}catch (Exception e){//Catch wanneer er errors zijn
    System.err.println("Error: " + e.getMessage());}
return line;
}



public void setNewcustomer(){
    // make a newSimpleInOutDialog     
    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();

}

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());
    }
    }

The changes need to be in be in getCustomer() Thanks!!

Hi , Solved my problem , here is the solution:

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{setNieuweKlant();}


    }catch (Exception e){//Catch wanneer er errors zijn
        System.err.println("Error: " + e.getMessage());}

}

回答1:

Use a HashSet to store all of the names you read and then it's just to call the contains methode to see if the customer already exists. If the names are stored on the forth line the code should look like this

HashSet<String> hs = new HashSet<String>();
int i = 0;
while ((line = br.readLine()) != null)
{
    i++;
       if (i % 4 == 0)
       {
          if(hs.contains(line))
             //name already exist
          else
            hs.add(line);
            // new customer do what you want with it

       }
}

来源：https://stackoverflow.com/questions/9589977/checking-if-a-customers-name-is-already-in-a-txt-file-with-filereader

标签

java

loops

while-loop

filereader