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Saving multiple input data in one .txt file. Is it possible to overwrite and get data from specific line?

Code first:
import java.io.*;
import java.util.Scanner;
public class Test {
public String date;
public String fridge1;
public String fridge2;
public String info;
static final int lineNumber = 0;
public Test(String date, String fridge1, String fridge2, String info) {
this.date = date;
this.fridge1 = fridge1;
this.fridge2 = fridge2;
this.info = info;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getFridge1() {
return fridge1;
}
public void setFridge1(String fridge1) {
this.fridge1 = fridge1;
}
public String getFridge2() {
return fridge2;
}
public void setFridge2(String fridge2) {
this.fridge2 = fridge2;
}
public String getInfo() {
return info;
}
public void setInfo(String info) {
this.info = info;
}
#Override
public String toString() {
return
date + "\n" +
fridge1 + "\n" +
fridge2 + "\n" +
info + "\n";
}
public void saveData() {
File file = new File("text.txt");
boolean checker = true;
try (Scanner scanner = new Scanner(file)) {
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
if (line.contains(date)) {
checker = false;
break;
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
if (checker) {
try (FileOutputStream fos = new FileOutputStream("text.txt", true)) {
fos.write(toString().getBytes());
} catch (IOException e) {
e.printStackTrace();
}
} else {
...
}
}
}
import java.io.IOException;
public class Main {
public static void main(String[] args) throws IOException {
// Test test = new Test("19/02/1992", "10", "9", "ok");
// test.saveData();
Test test2 = new Test("19/02/1900", "8", "4", "not ok");
test2.saveData();
}
}
I want to do program in Java to get some inputs and date, mostly Strings. I just create a methods to write all data in one .txt file, one data - 1 line. If there is already existing date program is not writing new data. Finally, I would like to overwrite data. If I put the same date in, I would like to overwrite existing date to new one. So in my mind if I have in .txt file this data:
line1 17/05/16 line2 blabla line3 blabla line4 blabla
and I will put in Main this:
Test test2 = new Test("17/05/16", "8", "4", "not ok");
test2.saveData();
it should find where is 17/05/16 and then replace lines 2-4 like this.
line1 17/05/16
line2 8
line3 4
line4 not ok
It is possible? Then how to find out all data in reverse way? In mean when I would like to check my data from specific date ex. 17/05/16?
As you can see I just stuck in moment when I have to search where is my data. I can't find good methods.

When your program does start, your first step must always be reading whole text file into memory, line by line. Visit this page how you can achive it. Use your timestamp as key for the HashMap.
One advantage of HashMap is, you can easily check of occurences or add some data at the end. And if you want just update an existing entry, use the same key and the content will be overwritten.
After this, the next page demonstrate how to write the content back to your text file.
Please note: As I wrote in comment section the use of Spring Boot is a better option for your task.

Java: How do I iterate through a file with multiple lines, then extract specific lines after filtering delimiters?

Clarification: I have a text file with multiple lines and I want to separate specific lines into fields for an object.
I have been banging my head against a wall for about 3 days now, and I feel as if I'm overthinking this.
import java.io.*;
import java.util.*;
public class ReadFile {
public static void main(String[] args) throws FileNotFoundException {
String fileName = null;
Scanner input = new Scanner(System.in);
System.out.print("Enter file path: ");
fileName = input.nextLine();
input.close();
String fileText = readFile(fileName);
System.out.println(fileText);
}
public static String readFile(String fileName) throws FileNotFoundException {
String fileText = "";
String lineText = "";
File newFile = new File(fileName);
if (newFile.canRead()) {
try (Scanner scanFile = new Scanner(newFile)) {
while (scanFile.hasNext()) {
lineText = scanFile.nextLine();
if (lineText.startsWith("+")) {
}
else {
fileText = fileText + lineText + "\n";
}
}
} catch (Exception e) {
System.out.println(e);
}
} else {
System.out.println("No file found. Please try again.");
}
return fileText;
}
}
My goal is to take a file that looks similar to this (this is the whole file, imagine a .txt with exactly this in it):
Name of Person
----
Clothing:
Graphic TeeShirt
This shirt has a fun logo of
depicting stackoverflow and a horizon.
****
Brown Slacks
These slacks reach to the floor and
barely cover the ankles.
****
Worn Sandals
The straps on the sandals are frayed,
and the soles are obviously worn.
----
Then I need to extract the top line (e.g.: "Graphic TeeShirt") as a type of clothing the object is wearing, then "This shirt has a fun [...]" as the description of that object.
I have another .java with setters/getters/constructors, but I can't figure out how to iterate through the text file.
Edit: I know I loop through each line, but I need to create an object that has the person's name as a field, the item name (Graphic TeeShirt) as a field, then the description under the item as the next field. Then the next object will be a new object with person's name as a field, the next item (Brown Slacks) as a field, then the description as a field.
I don't know how to separate the lines in to the fields I need.

As I mentioned, the data file format is lousy, which is the real source of the problem, but your delimiters can be used to help out a little. You might approach the problem this way. Obviously don't dump your code like I've done into main but this might start you off. You still need to separate the clothing names from their descriptions but you should get the idea from the below. You can then start making a pojo out of the data.
Pass the path to your data file to this app and look out for the metadata debug outputs of 'Name' and 'Item'.
import java.util.Scanner;
import java.nio.file.Paths;
public class PersonParser {
public static void main(String[] args) {
try {
try (Scanner scPeople = new Scanner(Paths.get(args[0]))) {
scPeople.useDelimiter("----+");
int tokenCount = 0;
while (scPeople.hasNext()) {
String token = scPeople.next();
if (tokenCount % 2 == 0) {
System.out.printf("Name: %s", token);
} else {
// Parse clothing
Scanner scClothing = new Scanner(token);
scClothing.useDelimiter("\\*\\*\\*+");
while (scClothing.hasNext()) {
String item = scClothing.next();
System.out.printf("Item: %s", item);
}
}
tokenCount++;
}
}
} catch (Throwable t) {
t.printStackTrace();
}
}
}

The following code is according to the details in your question, namely:
The sample file in your question is the entire file.
You want to create instances of objects that have the following three attributes:
Person's name.
Name of an item of clothing.
Description of that item.
Note that rather than ask the user for the name of the file, I simply use a hard-coded file name. Also note that method toString, in the below code, is simply for testing purposes. The code also uses try-with-resources and method references.
public class ReadFile {
private static final String DELIM = "****";
private static final String LAST = "----";
private String name;
private String item;
private String description;
public void setName(String name) {
this.name = name;
}
public String getItem() {
return item;
}
public void setItem(String item) {
this.item = item;
}
public void setDescription(String description) {
this.description = description;
}
public String toString() {
return String.format("%s | %s | %s", name, item, description);
}
public static void main(String[] strings) {
try (FileReader fr = new FileReader("clothing.txt");
BufferedReader br = new BufferedReader(fr)) {
String line = br.readLine();
String name = line;
br.readLine();
br.readLine();
line = br.readLine();
String item = line;
List<ReadFile> list = new ArrayList<>();
ReadFile instance = new ReadFile();
instance.setName(name);
instance.setItem(item);
line = br.readLine();
StringBuilder description = new StringBuilder();
while (line != null && !LAST.equals(line)) {
if (DELIM.equals(line)) {
instance.setDescription(description.toString());
list.add(instance);
instance = new ReadFile();
instance.setName(name);
description.delete(0, description.length());
}
else {
if (instance.getItem() == null) {
instance.setItem(line);
}
else {
description.append(line);
}
}
line = br.readLine();
}
if (description.length() > 0) {
instance.setDescription(description.toString());
list.add(instance);
}
list.forEach(System.out::println);
}
catch (IOException xIo) {
xIo.printStackTrace();
}
}
}
Running the above code produces the following output:
Name of Person | Graphic TeeShirt | This shirt has a fun logo ofdepicting stackoverflow and a horizon.
Name of Person | Brown Slacks | These slacks reach to the floor andbarely cover the ankles.
Name of Person | Worn Sandals | The straps on the sandals are frayed,and the soles are obviously worn.

It's not clear what you want to achieve and what is your issue exactly. You said that you can't figure out how to iterate through a text file, so let's dive into this fairly straightforward task.
In general, you have a valid, but the overcomplicated method for reading a file. Modern versions of Java provide a lot simpler methods and it's better to use them (only if you're not implementing some test task to understand how everything is working under the hood).
Please see my example below for reading a file line by line using Java NIO and Streams APIs:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Scanner;
import java.util.stream.Stream;
public class Test {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter file path: ");
String fileName = input.nextLine();
input.close();
Path path = Paths.get(fileName);
try (Stream<String> lines = Files.lines(path)) {
lines.filter(line -> {
// filter your lines on some predicate
return line.startsWith("+");
});
// do the mapping to your object
} catch (IOException e) {
throw new IllegalArgumentException("Incorrect file path");
}
}
}
This should allow you to filter the lines from your files based on some predicate and later to the mapping to your POJO if you intend to do so.
If you have any other issues besides reading the file and filtering its content, please add clarification to your questions. Preferably, with examples and test data.

Separating Parsing Method

I'm creating a program which handles SKU's. I currently have two classes in my program, the SKU class is the main class and a Store class in which an ArrayList is initialised and SKU objects are stored in the array. I currently have a method in my SKU class which takes input from a file, parses the data and stores the data using a String tokenizer in the objects variables and adds the objects to the array in the Store class. The problem I'm facing is that I'm wanting to separate the parsing method in the SKU class so that it simply reads from a line, and then have a separate method which takes a file input for the parser and finally update my Store class so that it initialises the products with the parsed data. Please, can you help me in regards to this?
My parsing method in the SKU class is currently as follows:
public void parser() {
try {
// create a Buffered Reader object instance with a FileReader
BufferedReader br = new BufferedReader(new FileReader("products.txt"));
// read from first line from the text file
String fileRead = br.readLine();
// skip first line from sample file as it contains headings
int lineNumber = 0;
// loop until all lines are read
while (fileRead != null)
{
if(lineNumber == 0) {
lineNumber++;
continue;
}
lineNumber++;
// use string.split to load a string array with the values from each line of
// the file, using a tab as the delimiter
String[] tokenize = fileRead.split("\t");
// assume file is made correctly
// and make temporary variables for the three types of data
String tempProductCode = tokenize[0];
String tempDescription = tokenize[1];
BigDecimal tempPrice = new BigDecimal(tokenize[2]);
// create temporary instance of SKU object
// and load with three data values
SKU tempObj = new SKU();
tempObj.setProductCode(tempProductCode);
tempObj.setDescription(tempDescription);
tempObj.setPrice(tempPrice);
// add to array list
Store.mySkuArrayList.add(tempObj);
// read next line before looping
// if end of file reached
fileRead = br.readLine();
}
// close file stream
br.close();
}
// handle exceptions
catch (FileNotFoundException fnfe)
{
System.out.println("file not found");
}
catch (IOException ioe)
{
ioe.printStackTrace();
}
}
My Store class is as follows:
public class Store {
public static ArrayList<SKU> mySkuArrayList = new ArrayList<SKU>();
public void addSKU(SKU sku) {
mySkuArrayList.add(sku);
}

Split your code to three separate classes. SkuFile class represents text file where sku codes is stored, this class knows how to every sku entry stored and able to parse it. Sku class contains data. Store class contains
list of Sku and accept SkuFile in it's constructor.
class SkuFile {
private String path;
SkuFile(String path) {
this.path = path;
}
List<Sku> readAllSku() {
ArrayList<Sku> result = new ArrayList<>();
try {
List<String> lines = Files.readAllLines(new File(path).toPath());
for(String skuLine : lines) {
result.add(parseFrom(skuLine));
}
} catch (IOException e) {
throw new RuntimeException(e);
}
return result;
}
private Sku parseFrom(String data){
String[] tokenize = data.split("\t");
productCode = tokenize[0];
description = tokenize[1];
price = new BigDecimal(tokenize[2]);
return new Sku(productCode, description, price);
}
}
class Sku {
private String code;
private String description;
private BigDecimal price;
Sku(String code, String description, BigDecimal price) {
this.code = code;
this.description = description;
this.price = price;
}
//getters setters methods
}
class Store {
private List<Sku> skus;
Store(SkuFile file) {
skus = file.readAllSku();
}
}
class Test {
public static void main(String[] args) {
Store store = new Store(new SkuFile("products.txt"));
}
}

One way to handle this is by making the parse method return a list of tokenizers(e.g. List tokenizeList) and a second method which takes that list as input and populates the SkuArrayList
Possible implementation of the parser method
public List<String[]> parser() {
List<String[]> tokenizeList = new ArrayList<>();
try {
... /*file opening logic*/
while (fileRead != null)
{
.../*line counting logic*/
String[] tokenize = fileRead.split("\t");
tokenizeList.add(tokenize);
fileRead = br.readLine();
}
// close file stream
br.close();
}// handle exceptions
catch (FileNotFoundException fnfe)
{
System.out.println("file not found");
}
catch (IOException ioe)
{
ioe.printStackTrace();
}
return tokenizeList;
}
Possible implementation of the populate store method
public void populateStore(List<String[]> tokenizeList) {
for(String[] tokenize: tokenizeList) {
String tempProductCode = tokenize[0];
String tempDescription = tokenize[1];
BigDecimal tempPrice = new BigDecimal(tokenize[2]);
SKU tempObj = new SKU();
tempObj.setProductCode(tempProductCode);
tempObj.setDescription(tempDescription);
tempObj.setPrice(tempPrice);
// add to array list
Store.mySkuArrayList.add(tempObj);
}
}
And the main method from where you call these two methods
public void foo() {
populateStore(parser());
}

ArrayOutofBoundsException - Attempting to read to/from file into Hash Map

I'm working on a homework assignment and have run into an odd "ArrayOutOfBoundsException" error - I know what the error means (essentially I'm trying to reference a location in an array that isn't there) but I'm not sure why it's throwing that error? I'm not sure what I'm missing, but obviously there must be some logic error somewhere that I'm not seeing.
PhoneDirectory.java
import java.util.HashMap;
import java.io.*;
class PhoneDirectory {
private HashMap<String, String> directoryMap;
File directory;
public PhoneDirectory() { //create file for phone-directory
directory = new File("phone-directory.txt");
directoryMap = new HashMap<String, String>();
try(BufferedReader buffer = new BufferedReader(new FileReader(directory))) {
String currentLine;
while((currentLine = buffer.readLine()) != null) { //set currentLine = buffer.readLine() and check if not null
String[] fileData = currentLine.split(","); //create array of values in text file - split by comma
directoryMap.put(fileData[0], fileData[1]); //add item to directoryMap
}
}
catch(IOException err) {
err.printStackTrace();
}
}
public PhoneDirectory(String phoneDirectoryFile) {
directory = new File(phoneDirectoryFile);
directoryMap = new HashMap<String, String>();
try(BufferedReader buffer = new BufferedReader(new FileReader(directory))) {
String currentLine;
while((currentLine = buffer.readLine()) != null) { //set currentLine = buffer.readLine() and check if not null
String[] fileData = currentLine.split(","); //create array of values in text file - split by comma
directoryMap.put(fileData[0], fileData[1]); //add item to directoryMap
}
}
catch(IOException err) {
err.printStackTrace();
}
}
public String Lookup(String personName) {
if(directoryMap.containsKey(personName))
return directoryMap.get(personName);
else
return "This person is not in the directory.";
}
public void AddOrChangeEntry(String name, String phoneNumber) {
//ASK IF "IF-ELSE" CHECK IS NECESSARY
if(directoryMap.containsKey(name))
directoryMap.put(name,phoneNumber); //if name is a key, update listing
else
directoryMap.put(name, phoneNumber); //otherwise - create new entry with name
}
public void DeleteEntry(String name) {
if(directoryMap.containsKey(name))
directoryMap.remove(name);
else
System.out.println("The person you are looking for is not in this directory.");
}
public void Write() {
try(BufferedWriter writeDestination = new BufferedWriter(new FileWriter(directory)))
{
for(String key : directoryMap.keySet())
{
writeDestination.write(key + ", " + directoryMap.get(key) + '\n');
writeDestination.newLine();
}
}
catch(IOException err) {
err.printStackTrace();
}
}
}
Driver.java
public class Driver {
PhoneDirectory list1;
public static void main(String[] args) {
PhoneDirectory list1 = new PhoneDirectory("test.txt");
list1.AddOrChangeEntry("Disney World","123-456-7890");
list1.Write();
}
}
Essentially I'm creating a file called "test.txt" and adding the line "Disney World, 123-456-7890" - what's weird is that the code still works - but it throws me that error anyway, so what's really happening? (For the record, I'm referring to the line(s): directoryMap.put(fileData[0], fileData[1]) - which would be line 14 and 28 respectively.)

writeFile() method not working

I am trying to write to a text file. I am able to write to the console however, i am not able to write to my text file. One thing i have noticed is that String data doesn't contain any data if i were to just print to the console which is probably why nothing appears in my textfile. Does anyone know why that is though and how i can come about it?
writeFile() method code:
public static void writeFile(String filename, String content) throws IOException
{
try
{
Files.write(Paths.get(filename), content.getBytes()); // write file
}
catch (IOException e)
{
System.out.println("Error writing file: " + e);
}
}
Test code:
public class QuickTest {
public static void main(String... p) throws IOException {
List<SensorInfo> readings = new ArrayList<>();
SensorInfo info = null;
String data = createStringFromInfo(readings);
writeFile("datastore.txt", data);
String filedata = readFile("client-temp.txt");
List<SensorInfo> temps = createInfoFromData(filedata);
System.out.println(header());
for (SensorInfo reading : temps) {
System.out.print(reading.display());
}
}
}
CreateFromInfo Method:
public static String createStringFromInfo(List<SensorInfo> infoList)
{
String data = "";
for (SensorInfo info : infoList)
{
data += info.asData();
}
return data;
}
createInfoFromData
public static List<SensorInfo> createInfoFromData(String data)
{
List<SensorInfo> infoList = new ArrayList<>();
String[] lines = data.split("\n");
for (String line : lines)
{
SensorInfo info = new SensorInfo(line);
infoList.add(info);
}
return infoList;
}

That implementation of createStringFromInfo() confirms my guess: it will return an empty string when its argument is an empty list, as is the case in your program. I agree with you that that is why you get an empty file.
You fix it by filling the readings list with SensorInfo objects describing the information you want written to the file (before you invoke createStringFromInfo()). If the data for those SensorInfo objects should come from reading file "client-temp.txt" then you should read it in first, then pass that List to createStringFromInfo() to get the data to write.