Java Reading String with multiple line - java

I have a string with multiple line, I want to display them individually example when I only want to display the first inline it will show only 'apple'
Example display line 1 = orange
What i haven done is as follows, it can display all but unable to select which fruit position to display
public static void main(String args[]) {
String fruit = "apple" + "\n" + "orange"+"\n"+"pear";
BufferedReader br = null;
try {
String sCurrentLine;
br = new BufferedReader(new StringReader(fruit));
while ((sCurrentLine = br.readLine()) != null) {
System.out.println(sCurrentLine);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null) {
br.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
output:
apple
orange
pear

Try using String#split instead, for example...
String fruit = "apple" + "\n" + "orange"+"\n"+"pear";
String[] basket = fruit.split("\n");
This will allow you to access each element individually by index

Related

Read, and then split a text file into different arrays

So I'm trying to use a BufferedReader to split a text file into 2 different arrays, I've written some code but I'm not sure where to go from here.
I know how to populate an array, but i just cant seem to get the specific lines.
So, one array for NEW_OFFICE containing only the numbers, and one for MAIN_ADDRESS containing only the numbers below it.
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader("myDelivery.txt"));
String read = null;
while ((read = in.readLine()) != null) {
String words = read.split("NEW_OFFICE")[0];
}
} catch (IOException e) {
System.out.println("There was a problem: " + e);
e.printStackTrace();
} finally {
try {
in.close();
} catch (Exception ignored) { }
}
This is the text file:
NEW_OFFICE
-92.48392883 52.96531732
-2.483984994 92.48392883
MAIN_ADDRESS
-1.207614869 52.98908196
NEW_OFFICE always is the first line, and always has two lines below
it, the same goes for MAIN_ADDRESS it always has one line below it.
NEW_OFFICE & MAIN_ADDRESS can't appear more than once.
Based on your comment mentioned above, given below is the solution:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
public class Main {
public static void main(String[] args) throws IOException {
String[][] office = new String[2][2];
String[][] main = new String[1][2];
try (BufferedReader in = new BufferedReader(new FileReader("myDelivery.txt"))) {
String read;
while ((read = in.readLine()) != null) {
if (read.equalsIgnoreCase("NEW_OFFICE")) {
// Read next two lines
for (int i = 0; i < 2; i++) {
if ((read = in.readLine()) != null) {
office[i] = read.split("\\s+");
}
}
} else if (read.equalsIgnoreCase("MAIN_ADDRESS")) {
// Read next line
if ((read = in.readLine()) != null) {
main[0] = read.split("\\s+");
}
}
}
}
// Display office[][]
System.out.println("Displaying office:");
for (String[] officeData : office) {
System.out.println(Arrays.toString(officeData));
}
// Display main[][]
System.out.println("Displaying main:");
for (String[] mainData : main) {
System.out.println(Arrays.toString(mainData));
}
}
}
Output:
Displaying office:
[-92.48392883, 52.96531732]
[-2.483984994, 92.48392883]
Displaying main:
[-1.207614869, 52.98908196]
Notes:
\\s+ is for splitting the line on space(s).
Use try-with-resources syntax to simplify your code.
.split() does take a string, but it should be a regex, not the substring that you want to split it on. You want to change your code like this:
try (BufferedReader in = new BufferedReader(new FileReader("x.txt"))) {
String read;
String office = "";
while ((read = in.readLine()) != null) {
if (read.contains("NEW_OFFICE")) {
office = "NEW_OFFICE";
} else if (read.contains("MAIN_ADDRESS")) {
office = "MAIN_ADDRESS";
} else {
System.out.println(office + " : " + read);
}
}
} catch (IOException e) {
e.printStackTrace();
}
I have also changed your try with try-with-resources so you don't have to worry about closing the resource.
I´d go with somethin like this.
Please be aware that I don´t have an IDE right now so this is basically pseudo code:
try (BufferedReader in = new BufferedReader(new FileReader("x.txt"))) {
String line = null;
boolean isOffice = false;
ArrayList<double> officeInts = new ArrayList<double>();
ArrayList<double> addressInts = new ArrayList<double>();
while ((line = in.readLine()) != null) {
if (line.contains("NEW_OFFICE")) {
isOffice = true;
continue;
} else if (line.contains("MAIN_ADDRESS")) {
isOffice = false;
continue;
}
for(String s : line.split(" "){
double num = Double.parseDouble(s);
if(isOffice) {
officeInts.add(num);
} else {
addressInts.add(num);
}
}
}
} catch (IOException e) {
e.printStackTrace();
}

Parsing strings with split JAVA

I'm trying to find an object in a list from a text file
Example:
L;10;€10,50;83259875;YellowPaint
-H;U;30;€12,00;98123742;Hammer
G;U;80;€15,00;87589302;Seeds
By inserting 98123742 by input with scanner, i want to find that string.
I tried to do this:
private static void inputCode() throws IOException {
String code;
String line = null;
boolean retVal = false;
System.out.println("\ninsert code: ");
code = in.next();
try {
FileReader fileReader = new FileReader("SHOP.txt");
BufferedReader bufferedReader = new BufferedReader(fileReader);
while ((line = bufferedReader.readLine()) != null) {
String[] token = line.split(";");
if (token[0].equals(code) && token[1].equals(code)) {
retVal = true;
System.out.println(line);
}
}
bufferedReader.close();
} catch (FileNotFoundException ex) {
System.out.println("impossible open the file " + fileName);
}
catch(IOException ex) {
System.out.println(
"Error reading file '"
+ fileName + "'");
}
System.out.println(retVal);
}
How can i print "-H;U;30;€12,00;98123742;Hammer" inserting "98123742" (that is the code of the product) ?
Why are you splitting in the first place? For such a simple usecase, and with that line format, I'd go with
line.contains(";" + code);
Not much else to do.

Write to a specific line in a txt document java

I know that there are already some posts about this problem but I don't understand them.
My problem is that I want to find a line in a txt document with a name and I then want to change the next line to the content of a string.
This is what I tried:
public void saveDocument(String name) {
String documentToSave = textArea1.getText();
File file = new File("documents.txt");
Scanner scanner;
BufferedWriter bw;
try {
scanner = new Scanner(file);
bw = new BufferedWriter(new FileWriter(file));
while(scanner.hasNextLine()) {
if(scanner.nextLine().equals(name)) {
if(scanner.hasNextLine()) bw.write(scanner.nextLine() + "\n");
bw.write(documentToSave + "\n");
if(scanner.hasNextLine()) scanner.nextLine();
}
if(scanner.hasNextLine()) bw.write(scanner.nextLine() + "\n");
}
bw.flush();
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
May be you try it this way: read your file and keep each line in a list of strings and if you find the name you are looking for replace the next line you read. And then write the strings from that list back to your file. Example:
public class NewClass {
public static void main(String[] args) {
List<String> list = new ArrayList<String>();
list = readFile("uzochi");
writeToFile(list);
}
public static List<String> readFile(String name){
List<String> list = new ArrayList<String>();
try {
FileReader reader = new FileReader("C:\\users\\uzochi\\desktop\\txt.txt");
BufferedReader bufferedReader = new BufferedReader(reader);
String line;
boolean nameFound = false;
while ((line = bufferedReader.readLine()) != null) {
if(line.equalsIgnoreCase(name)){
nameFound = true;
System.out.println("searched name: "+line);
}
if(nameFound){
list.add(line);
line = bufferedReader.readLine();
System.out.println("line to replace: " + line);
line = "another string";
System.out.println("replaced line: "+line);
list.add(line);
nameFound = false;
}
else{
list.add(line);
}
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
return list;
}
public static void writeToFile(List<String> list){
try {
FileWriter writer = new FileWriter("C:\\users\\uzochi\\desktop\\txt.txt", false);
BufferedWriter bufferedWriter = new BufferedWriter(writer);
for(String s: list){
bufferedWriter.write(s);
bufferedWriter.newLine();
}
bufferedWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
txt.txt
hallo
hello
hola
uzochi
world
java
print
This code should read the entire file and replace the line with the name.
while(scanner.hasNextLine()) {
String line = scanner.nextLine();
if(line.equals(name)) {
bw.write(documentToSave + "\n");
} else {
bw.write(line + "\n");
}
}
This program will replace the line after a given line. It needs some more work from us, for example if we can define expected i/o and usage. Now it reads from a file and reeplaces a line, but maybe you want to use the line number instead of the line contents to mark which line to replace.
import java.io.*;
public class FileLineReplace {
public static void replaceSelected(String replaceWith, String type) {
try {
String input2 = "";
boolean replace = false;
String input = "";
try (BufferedReader br = new BufferedReader(new FileReader("data.txt"))) {
for (String line;
(line = br.readLine()) != null;) {
// process the line.
System.out.println(line); // check that it's inputted right
if (replace) {
line = "*** REPLACED ***";
replace = false;
}
if (line.indexOf("replaceNextLine") > -1) {
replace = true;
}
input2 = input2 += (line + "\n");
}
// line is not visible here.
}
// check if the new input is right
System.out.println("----------------------------------" + '\n' + input2);
// write the new String with the replaced line OVER the same file
FileOutputStream fileOut = new FileOutputStream("data.txt");
fileOut.write(input2.getBytes());
fileOut.close();
} catch (Exception e) {
System.out.println("Problem reading file.");
e.printStackTrace();
}
}
public static void main(String[] args) {
replaceSelected("1 adam 20 M", "foobar");
}
}
If you run the code, it will replace next line after a line which is "replaceNextLine":
$ java FileLineReplace
asd
zxc
xcv
replaceNextLine
wer
qwe
----------------------------------
asd
zxc
xcv
replaceNextLine
*** REPLACED ***
qwe
My test file is (was)
asd
zxc
xcv
replaceNextLine
wer
qwe
After I run the program, the file looks like this and the line after the specified line is replaced.
asd
zxc
xcv
replaceNextLine
*** REPLACED ***
qwe

Java Read/Write, Rename File having issue

I was using my code to do a replace line feature. It was working initially but suddenly my new file became blank and the code did not bring me back to the AdminMenu(), as well as the file not being renamed. There is also another issue where if I use "\r\n" there will be a blank line on top of my file which I am trying to remove. I tried using \n after totalChips, but it doesn't seem to work. I could use some advice on this.
output
<Blank File>
expected output
Line1|password|500
Line2|password|600
//ModifiedLine can be either line based on UserName
codes are below
public static void AddChips() {
File oldFileName = new File("players.dat");
File tmpFileName = new File("newplayers.dat");
BufferedReader br = null;
BufferedWriter bw = null;
ArrayList<String> player = new ArrayList<String>();
try {
br = new BufferedReader(new FileReader(oldFileName));
bw = new BufferedWriter(new FileWriter(tmpFileName));
String line;
Scanner read = new Scanner(System.in);
System.out.println("Please Enter Username");
String UserN = read.nextLine();
System.out.println("Please Enter Chips to Add");
String UserCadd = read.nextLine();
while ((line = br.readLine()) != null) {
String[] details = line.split("\\|");
String Username = details[0];
String Password = details[1];
String Chips = details[2];
int totalChips = (Integer.parseInt(UserCadd)+ Integer.parseInt(Chips));
if (Username.equals(UserN))
line = Username + "|" + Password + "|" + totalChips;
bw.write("\r\n"+line);
}
bw.close();
br.close();
oldFileName.delete();
tmpFileName.renameTo(oldFileName);
AdminMenu();
} catch (Exception e) {
e.printStackTrace();
return;
} finally {
try {
if(br != null)
br.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if(bw != null)
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
new Error
java.lang.ArrayIndexOutOfBoundsException: 1
at testcode.AddChips(testcode.java:53)
at testcode.main(testcode.java:11)

how to remove double quotes while reading CSV

public class CSVTeast {
public static void main(String[] args) {
CSVTeast obj = new CSVTeast();
obj.run();
}
public void run() {
String csvFile = "D:\\text.csv";
BufferedReader br = null;
String line = "";
String cvsSplitBy = "~";
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
// use comma as separator
String[] csvRead = line.split(cvsSplitBy);
System.out.println("Value [date= " + csvRead[5]
+ " , name=" + csvRead[9]+"]");
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Done");
}
}
Output is
Value [date= "POLICY_CHANGE_EFFECTIVE_DATE" , name="AGENCY_NAME"]
Value [date= "2014-04-01" , name="USI INSURANCE SERVICES]--this value stated with double qoutes but not end with same .
Expected output
Value [date= POLICY_CHANGE_EFFECTIVE_DATE , name=AGENCY_NAME]
Value [date= 2014-04-01 , name=USI INSURANCE SERVICES]
You can try passing the value through the String.replace() method.
So your code would be:
public class CSVTeast {
public static void main(String[] args) {
CSVTeast obj = new CSVTeast();
obj.run();
}
public void run() {
String csvFile = "D:\\text.csv";
BufferedReader br = null;
String line = "";
String cvsSplitBy = "~";
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
String[] csvRead = line.split(cvsSplitBy);
System.out.println("Value [date= " + csvRead[5].replace("\"","")
+ " , name=" + csvRead[9].replace("\"","")+"]");
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Done");
}
}
There's a nice CSV Reader for Java that will handle the mess of this for you, http://opencsv.sourceforge.net/
It has a maven package if your project is maven, else you can download the JARs there.
If the qoutemarks are at the beginning of every CSV line, you can do:
csvRead[5].substring(1, csvRead[5].length()-1)
That will remove the first and last character of that particular string. You then need to store the results somewhere or print it out.
It is also important to check if the String starts with a double quote, otherwise the code will start deleting the first character of the CSV value. I do this in my code in one of my apps, where my CSV value is coming in rowData[1] which sometimes have double quotes and sometimes it doesn't, depending upon the number of words in the value String.
String item = (String.valueOf(rowData[1].charAt(0)).equals("\"") ? rowData[1].substring(1, rowData[1].length() - 1) : rowData[1]);

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