When I delete a record first before inserting a new record, I can do it, and after deleting I can add new record. But if I insert a new record first then my delete function is not working. Based on my research, it's mainly because the input/output is not closed properly but I have already done that, please take a look at my source code thank you.
Insert record
public void RegCustomer()
{
try
{
File F = new File("Customer.txt");
FileWriter fw = new FileWriter(F, true);
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter pw = new PrintWriter(bw);
//PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(F, true)));
pw.println(this.Name+","+this.CheckInDate+","+this.CheckOutDate+","+this.Floor+","+this.RoomID+","+this.ICNumber+","+this.Contact+","+this.Email);
pw.flush();
pw.close();
fw.close();
bw.close();
}
catch(Exception e)
{
}
}
Delete Record
public boolean delcus(String Target)
{
boolean success = false;
File F = new File("Customer.txt");
File Ftc = new File("Temp.txt");
try
{
FileReader fr = new FileReader(F);
BufferedReader br = new BufferedReader(fr);
PrintWriter pr = new PrintWriter(Ftc);
String line = br.readLine();
while (line!=null)
{
String[] wordsinLine = line.split(",");
if (wordsinLine[0].equals(Target))
{
}
else
{
pr.println(line);
success = true;
}
line = br.readLine();
}
if (success)
{
pr.flush();
pr.close();
br.close();
fr.close();
}
}
catch (Exception e)
{
}
F.delete();
File dump = new File("Customer.txt");
Ftc.renameTo(dump);
return success;
}
I have another method that checks for several conditions before triggering the insert method.
public int checkroom()
{
int check = 0;
int ciDay = this.CheckInDate/10000;
int ciMonth = (this.CheckInDate/100)%100;
int coDay = this.CheckOutDate/10000;
int days = coDay - ciDay;
String name;
int Dbcid;
int Dbcod;
int DbFloor;
int DbRoomID;
try
{
File F = new File("Customer.txt");
FileReader Fr = new FileReader(F);
BufferedReader Reader = new BufferedReader(Fr);
Scanner Sc = new Scanner(Reader);
Sc.useDelimiter("[,\n]");
while(Sc.hasNext())
{
name = Sc.next();
Dbcid = Sc.nextInt();
Dbcod = Sc.nextInt();
DbFloor = Sc.nextInt();
DbRoomID = Sc.nextInt();
if (days <= 7)
{
if (DbFloor == this.Floor && DbRoomID == this.RoomID)
{
int DbcidDay = Dbcid/10000;
int DbcidMonth = (Dbcid/100)%100;
int DbcodDay = Dbcod/10000;
if(ciMonth == DbcidMonth)
{
if (ciDay >= DbcidDay && ciDay < DbcodDay)
{
check = 2;
}
else if (coDay >= DbcidDay && coDay < DbcodDay)
{
check = 3;
}
else if (ciDay <= DbcidDay && coDay >= DbcodDay)
{
check = 4;
}
else
{
check = 1;
}
}
else
{
check = 1;
}
}
else
{
check =1;
}
}
else
{
check =5;
}
}
if(check > 0)
{
Sc.close();
Reader.close();
Fr.close();
}
}
catch (Exception e)
{
}
return check;
}
There are a few issues I can see:
You need to close your streams in a finally clause (or, better still, use a try-with-resource). Otherwise, if an exception is thrown that interrupts the normal program flow, your stream will not be closed immediately.
You should only close the outermost stream object (so e.g. your BufferedReader, but not the FileReader)
You are swallowing exceptions. At least do a printStackTrace() on the exceptions you catch so you can see if any are actually thrown.
Avoid methods like File.delete() that don't throw exceptions in the case of an error. Instead, use the equivalent methods on the Files.class, which throw exceptions in the event of an error.
Incidentally, although it's not an issue as such, you don't need to call flush() just before close()-- the latter automatically flushes before closing.
Related
I'm trying to read into a csv file and placing the line into an array. But when I print the array out it is null.
Here is the code:
public static String[] readFile(String inFilename)
{
int lineTotal = getLineNum(inFilename);
if (lineTotal == 0)
{
System.out.println("The file is empty ");
}
FileInputStream fileStrm = null;
InputStreamReader rdr;
BufferedReader bufRdr;
String[] resultArrayOne = new String[lineTotal + 1];
String line;
try
{
fileStrm = new FileInputStream(inFilename); //open file
rdr = new InputStreamReader(fileStrm); //create a reader to read the stream
bufRdr = new BufferedReader(rdr);//read file line by line
int lineNum;
String[] resultArray = new String[lineTotal];
String info;
lineNum = 0;
while ((line = bufRdr.readLine()) != null) //While not end-of-file, process and read lines
{
info = line;
System.out.println(info);
resultArray[lineNum] = info;
lineNum++;
}
fileStrm.close(); //Clean up the stream
resultArrayOne = resultArray;
}
catch (IOException e) // MUST catch IOExceptions
{
if (fileStrm != null) //Clean up the stream if it was opened
{
try
{
fileStrm.close();
}
catch (IOException ex2) { } // We can’t do anything more!
}
System.out.println("Error in file processing: " + e.getMessage()); //Or do a throw
}
return resultArrayOne;
}
When printing out the line before placing it into the array the return is fine, but when placed into the array it become null.
edit:
Here is the full FileIO code:
public static String[] Import()
{
Scanner sc = new Scanner(System.in);
System.out.println("Please enter the File Name: ");
String fileName = sc.nextLine();
int length = getLineNum(fileName);
String[] array = new String[length+1];
array = readFile(fileName);
return array; //array is just strings
}
public static int getLineNum(String inFilename)
{
FileInputStream fileStrm = null;
InputStreamReader rdr;
BufferedReader bufRdr;
String line;
int lineNum = 0;
try
{
fileStrm = new FileInputStream(inFilename); //open file
rdr = new InputStreamReader(fileStrm); //create a reader to read the stream
bufRdr = new BufferedReader(rdr);//read file line by line
lineNum = 0;
while ((line = bufRdr.readLine()) != null) //While not end-of-file, process and read lines
{
lineNum++;
}
fileStrm.close(); //Clean up the stream
}
catch (IOException e) // MUST catch IOExceptions
{
if (fileStrm != null) //Clean up the stream if it was opened
{
try
{
fileStrm.close();
}
catch (IOException ex2) { } // We can’t do anything more!
}
System.out.println("Error in file processing: " + e.getMessage()); //Or do a throw
}
return lineNum;
}
I'm not too sure how to insert a sample file but it is something like this:
SHOP1, STORE2, 45
SHOP2, SHOP1, 67
STORE6, SHOP1, 90
...
edit 2:
I added the code that uses this
String[] locationArrayOne = new String[1000];
locationArrayOne = FileIO.Import();
for (int yyy = 0; yyy < locationArrayOne.length; yyy++)
{
System.out.print(locationArray[yyy]);
}
Your code looks fine but here is how I would debug the problem:
Before lineNum++, I will print the value of resultArray[lineNum] instead of info to see if the program was able to retrieve the line and store it to the array.
Remove the initialization of String[] resultArrayOne and after fileStrm.close(), use resultArrayOne = resultArray.clone() to copy the values of resultArray to resultArrayOne. Copying an array by assignment (array1 = array2) could have side-effects you do not want in your program since you are making both arrays refer to the same object. Check this related question here
Also, why not use resultArrayOne directly when storing the lines?
I am reading, from a file, integer values that I should use to calculate the function multiple.
However, after converting to integer, it appears that the integer variable doesn't hold them for further calculation.
Any help please?
import java.io.*;
public class Functions {
int values, mul7, mul11, mul13;
public static void main (String []args) {
Functions go = new Functions ();
go.multiple();
// will call functions here
}
public void multiple () {
int a = 7;
int b = 11;
int c = 13;
try {
File inputFile = new File ("JavaInputData.txt");
FileReader fileReader = new FileReader (inputFile);
BufferedReader reader = new BufferedReader (fileReader);
String line = null;
while ((line = reader.readLine()) !=null)
{
values = Integer.parseInt(line);
System.out.println(values);
}
mul7 = values % a;
mul11 = values %b;
mul13 = values %c;
System.out.println(mul7);
reader.close();
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
}
Perform the calculation and output in the loop body. Something like,
while ((line = reader.readLine()) != null)
{
values = Integer.parseInt(line);
System.out.println(values);
mul7 = values % a;
mul11 = values % b;
mul13 = values % c;
System.out.printf("mul7 = %d, mul11 = %d, mul13 = %d%n", mul7, mul11, mul13);
}
Also, I suggest you use a try-with-resources to close() your Reader;
try (File inputFile = new File ("JavaInputData.txt");
FileReader fileReader = new FileReader (inputFile);
BufferedReader reader = new BufferedReader (fileReader)) {
That way you don't have to call close() explicitly. But, if you're going to call close() explicitly; please do so in a finally block.
I have been working on this code for the day and am almost at the finish line. What I want is that the code should work as a clip card, remembering the number of purchased coffees, and awarding the customer a free coffee every 10th purchase. I'm writing to a file and reading from it in order for a customer to be able to continue his clip card where he left of last time. So to my problem...I have properly been able to write my "count" variable to a file, and it is storing it correctly. However, every time I run the program again it starts off a 0 and I don't see why. I need it to save the current count, and read the count once run again. For example, if a customer has previously purchased 7 coffees and is returning to the store, his counter needs to start at 7. For some reason it is not doing that.
Here's what I have so far:
public class FelixNeww {
public static void main(String [] args) {
Scanner key;
String entry;
int count = 0;
String password = "knusan01";
FelixNeww f = new FelixNeww();
System.out.println(f.readFromFile());
while(true) {
System.out.println("Enter password: ");
key = new Scanner(System.in);
entry = key.nextLine();
if(entry.compareTo(password) == 0){
count++;
System.out.println("You're one step closer to a free coffe! You have so far bought "
+ count + " coffe(s)");
f.saveToFile(count);
}
if(count == 10 && count != 0){
System.out.println("YOU'VE GOT A FREE COFFE!");
count = 0;
}
if(entry.compareTo(password) != 0){
System.out.println("Wrong password! Try again.\n");
}
}
}
public void saveToFile(int count)
{
BufferedWriter bw = null;
try
{
bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File("C:\\Temp\\countStorage.txt"))));
bw.write(Integer.toString(count));
}
catch(IOException e)
{
e.printStackTrace();
}
finally
{
if(bw != null)
{
try
{
bw.close();
}
catch(IOException e) {}
}
}
}
public int readFromFile()
{
BufferedReader br = null;
try
{
br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("C:\\Temp\\countStorage.txt"))));
String line = br.readLine();
int count = Integer.parseInt(line);
return count;
}
catch(IOException e)
{
e.printStackTrace();
}
finally
{
if(br != null)
{
try
{
br.close();
}
catch(IOException e) {}
}
}
return 0;
}
}
You are currently setting your count variable to 0. You should set it to the value that's in the file. Do this just before the while loop:
count = f.readFromFile();
while(true) {
You should also implement a way to gracefully exit the while loop. For example, if the user enters "q", you can execute the break; statement to exit the while loop. And after your while loop, call key.close(); to close the Scanner object.
The scope of count variable is local in both instances
public static void main(String [] args) {
Scanner key;
String entry;
int count = 0;
String password = "knusan01";
System.out.println(f.readFromFile());
public int readFromFile()
{
BufferedReader br = null;
try
{
br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("C:\\Temp\\countStorage.txt"))));
String line = br.readLine();
int count = Integer.parseInt(line);
return count;
In the readFromFile function, you read it from the file, return it, but don't keep track of it in a variable, why don't you replace the println with this inside your main:
count=f.readFromFile
See my code below:
I can write a key and a string in one line of a file. If the key already exists I want to overwrite it by creating a new file and fill it with the content of my source file. In the end I am going to delete the old file and rename my temporary file. But it does not work. As you can see I print booleans for deleting and renameTo methods. Both are returned as "false".
I read in some other Threads that I have to close all Readers and Writers that are in contact with my file in order to be able to rename or delete it.
You see my fault?
(Note that some comments are written in german)
public static boolean dini_Set(String filepath, String key, String value) throws IOException
{
if(key.length() <= 0 || value.length() <= 0) return false;
String pfilepath = rootdirectory.concat(filepath);
File pfile = new File(pfilepath);
//dini_Remove(filepath.concat(".part"));
if(dini_Exists(filepath) == false) return false;
// Checkt ob der Key schon existiert
FileReader fr = new FileReader(pfilepath);
BufferedReader br = new BufferedReader(fr);
String ausw;
boolean foundkeybool = false;
while((ausw = br.readLine()) != null)
{
String foundkey = ausw.substring(0,ausw.indexOf("="));
//System.out.println(foundkey);
if(foundkey.equals(key))
{
foundkeybool = true;
System.out.println(foundkeybool);
// Key exists and content has to be overwritten
String newline = key.concat("=").concat(value);
String tmpdir = rootdirectory.concat("tmp.tmp");
File tmp = new File(tmpdir);
tmp.createNewFile();
String currentLine;
FileWriter fw = new FileWriter(tmpdir);
BufferedWriter bw = new BufferedWriter(fw);
br.close();
fr.close();
fr = new FileReader(pfilepath);
br = new BufferedReader(fr);
while((currentLine = br.readLine()) != null)
{
// trim newline when comparing with lineToRemove
String trimmedLine = currentLine.trim();
System.out.println(trimmedLine);
if(trimmedLine.equals(ausw))
{
System.out.println("Austauschen: "+newline);
bw.write(newline);
}
else
{
bw.write(currentLine);
System.out.println("Lassen: "+currentLine);
}
bw.newLine();
}
br.close();
fr.close();
bw.close();
fw.close();
tmp.setWritable(true);
pfile.setWritable(true);
// boolean removed = dini_Remove(filepath);
boolean removed = pfile.delete();
System.out.println("Datei wurde gelöscht: "+removed);
boolean renamed = tmp.renameTo(pfile);
System.out.println("Datei umbenannt: "+renamed);
break;
}
}
// if key does now exists we can create a new one
if(foundkeybool == false)
{
FileWriter fw = new FileWriter(pfilepath,true);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(key.concat("=").concat(value));
bw.newLine();
bw.close();
}
return true;
}
This may not fix your problem, but it will get you closer.
You MUST ensure that any resource that you open is closed properly. Currently in your code, if, for some reason, an exception is thrown, none of your resources will be closed.
Even if you're not interested in dealing with the exception within the method, you should still wrap the file access code within a try-finally block
FileReader fr = null;
BufferedReader br = null;
try {
fr = new FileReader(pfilepath);
br = new BufferedReader(fr);
//...//
} finally {
try {
br.close();
} catch (Exception exp) {
}
try {
fr.close();
} catch (Exception exp) {
}
}
You may find that you only need to close the BufferedReader and it should be calling close on it's child Reader, but I'm paranoid about ensuring that everything is clean
If you are using Java 7, you may wish to take a look at The try-with-resources Statement
Updated
I'm not sure your code makes sense. Basically, what you should be doing, is reading the entire source file and writing it the temp location (as you don't know in advance if the key needs to be updated, and you would probably need to read the source file anyway to find out).
Once this has being completed, if you made changes to the temp file, delete the source file and rename the temp file into it's place.
You code seems mighty inefficient to me...
Okai, I want to give you a brief update about the code.
I changed it this way and for now it is working as it should.
Do you have some more things I can change to optimize the code?
public static boolean dini_Set(String filepath, String key, String value) throws IOException
{
if(key.length() <= 0 || value.length() <= 0) return false;
String pfilepath = rootdirectory.concat(filepath);
File pfile = new File(pfilepath);
//dini_Remove(filepath.concat(".part"));
if(dini_Exists(filepath) == false) return false;
// Checkt ob der Key schon existiert
boolean foundkeybool = false;
File tmp = null;
try(BufferedReader br = new BufferedReader(new FileReader(pfilepath)))
{
String ausw;
while((ausw = br.readLine()) != null)
{
String foundkey = ausw.substring(0,ausw.indexOf("="));
System.out.println(foundkey);
if(foundkey.equals(key))
{
foundkeybool = true;
System.out.println(foundkeybool);
//Key exists and content has to be overwritten
String newline = key.concat("=").concat(value);
String tmpdir = rootdirectory.concat("tmp.tmp");
tmp = new File(tmpdir);
tmp.createNewFile();
String currentLine;
try(BufferedWriter bw = new BufferedWriter(new FileWriter(tmpdir)))
{
try(BufferedReader br2 = new BufferedReader(new FileReader(pfilepath)))
{
while((currentLine = br2.readLine()) != null)
{
//trim newline when comparing with lineToRemove
String trimmedLine = currentLine.trim();
System.out.println(trimmedLine);
if(trimmedLine.equals(ausw))
{
System.out.println("Austauschen: "+newline);
bw.write(newline);
}
else
{
bw.write(currentLine);
System.out.println("Lassen: "+currentLine);
}
bw.newLine();
}
}
}
break;
}
}
}
if(foundkeybool == true)
{
tmp.setWritable(true);
pfile.setWritable(true);
//boolean removed = dini_Remove(filepath);
boolean removed = pfile.delete();
System.out.println("Datei wurde gelöscht: "+removed);
boolean renamed = tmp.renameTo(pfile);
System.out.println("Datei umbenannt: "+renamed);
}
else //(foundkeybool == false) if key does now exists we can create a new one
{
try(BufferedWriter bw = new BufferedWriter(new FileWriter(pfilepath,true)))
{
bw.write(key.concat("=").concat(value));
bw.newLine();
bw.close();
}
}
return true;
}
It's not that my code doesn't work, but I am doubting whether it's very efficient or not. My theory is, that it isn't xD
I have a JTextPane where I have to take the text in it (Making a new line every time the JTextPane got a new line basically), and put it into a .txt file. As I said everything works but I am doubting the implementation of it.
This is the part I am doubting:
public void printLog() {
String s = logTextArea.getText();
ArrayList<String> log = new ArrayList<>();
StringBuilder sb = new StringBuilder();
for(int i = 0; i < s.length(); i++) {
if(s.charAt(i) != '\n') {
sb.append(s.charAt(i));
} else {
log.add(sb.toString());
sb.delete(0, sb.length());
}
}
This is the entire thing just for reference:
public void printLog() {
String s = logTextArea.getText();
ArrayList<String> log = new ArrayList<>();
StringBuilder sb = new StringBuilder();
for(int i = 0; i < s.length(); i++) {
if(s.charAt(i) != '\n') {
sb.append(s.charAt(i));
} else {
log.add(sb.toString());
sb.delete(0, sb.length());
}
}
File f = new File("JServer_Log.txt");
BufferedWriter bw = null;
FileWriter fr = null;
try {
if(f.exists()) {
fr = new FileWriter(f,true);
} else {
fr = new FileWriter(f);
}
} catch (IOException e) {
// Nothing to do really.
}
try {
bw = new BufferedWriter(fr);
Iterator<String> itr = log.iterator();
bw.newLine();
while(itr.hasNext()) {
bw.write(itr.next());
bw.newLine();
}
} catch (IOException e) {
// Nothing to do really. We lost the log?
} finally {
try {
bw.close();
} catch(IOException ioe) {
// The program is closing any way.
}
}
}
It seems that you just need to make sure you use the platform's appropriate newline sequence. You can just say s = s.replace("\n", System.getProperty("line.separator")) and then write that whole string directly to file. In fact, the way I see it, this is all the code you need (except maybe for exception handling, up to you):
public void printLog() throws IOException {
final FileWriter w = new FileWriter("JServer_Log.txt", true);
try {
w.write(logTextArea.getText().replace("\n",
System.getProperty("line.separator")));
} finally { w.close(); }
}
For information, the first code can be replaced by:
List<String> log = Arrays.asList(logTextArea.getText().split("\n"));
but other answers give you a way to replace the whole method.
Why bothering, to use JTextComponents.write(Writer out) throws IOExceptionwrite() this is pretty accepting newline, tabs, e.i. that came from Native OS
use split:
String[] log = s.split("\n");