Develop Reference

how to print string array onto file? [duplicate]

This question already has answers here:
What's the simplest way to print a Java array?
(37 answers)
Convert array of strings into a string in Java
(14 answers)
Closed last month.
I have a string input file and I put the strings into arrays. I only want to print the last element of each string array onto my console and onto a output array. When I run my code, I get the last element of each string array onto my console, but see this on my output file:
[Ljava.lang.String;#51d5f7fd
How can I print the actual string array to show up on output file and not its string representation? I'll show you my code so you get a better understanding of what I'm trying to do:
try {
br = new BufferedReader(new FileReader("C:\\rd\\bubble.txt"));
//first, create new file object
File file = new File("C:\\rd\\bubble_out.txt");
if(file.exists()) {
file.createNewFile();
}
PrintWriter pw = new PrintWriter(file);
String line = "";
while((line = br.readLine()) != null) { //while the line is not equal to null
String[] arr = line.split("\\s+"); //split at whitespace
System.out.println(arr[arr.length - 1]);
pw.println(arr);
pw.close();
}
}
catch(IOException x)
{
System.out.println("File not found");
}
}
}
}
}
I've tried using Array.toString() method, but I'm not sure how to implement it into my code correctly. I'm currently trying to do that, but if there's an easier way to do this, please let me know.

Use Arrays.toString to get a readable String representation of the array.
Don't close the PrintWriter inside the loop as you have not finished writing all output. You can use try with resources to avoid having to explicitly close it.
try (PrintWriter pw = new PrintWriter(file)) {
while((line = br.readLine()) != null) {
String[] arr = line.split("\\s+");
System.out.println(arr[arr.length - 1]);
pw.println(Arrays.toString(arr));
}
}

Read Data from text file in Java [duplicate]

This question already has answers here:
How can I read comma separated values from a text file in Java?
(6 answers)
How do I split a string in Java?
(39 answers)
Closed 3 years ago.
I want to load data from a text file as required for part of a basic project. E.g. a text file can look like this:
201,double,70.00,2,own bathroom
202,single,50.00,2,own bathroom
Each piece of data is seperated by a comma, and in this case goes in the order: room number, room type, cost, amount of people, with/without bathroom and there's 5 data for each room and each room information is on a new line.
The code below reads each line individually, but how do I get it to read and store each data/word from the line (without the comma obviously)?
try{
BufferedReader reader = new BufferedReader(new FileReader("test.txt"));
String line = reader.readLine();
while (line != null){
System.out.println(line);
line = reader.readLine();
}
reader.close();
} catch(IOException ex){
System.out.println(ex.getMessage());
}
I saw an example using scanner but I heard that it's slower and less efficient.
I also tried using split but I can't figure out how to do it properly.
Thanks.

You can use Files.readAllLines() method and map the data to the dedicated object. Assuming you have such Room object with appropriate constructor you can read and store data like:
List<String> strings = Files.readAllLines(Paths.get("test.txt"));
List<Room> rooms = new ArrayList<>();
for (String line : strings) {
String[] split = line.split(",");
Integer roomNumber = Integer.valueOf(split[0]);
String roomType = split[1];
Double roomCost = Double.valueOf(split[2]);
Integer amount = Integer.valueOf(split[3]);
String bathroom = split[4];
Room r = new Room(roomNumber, roomType, roomCost, amount, bathroom);
rooms.add(r);
}
Then you can get the information for some room for example by room number:
Room room = rooms.stream()
.filter(r -> r.getRoomNumber() == 102)
.findFirst().orElseThrow(NoSuchElementException::new);
Note: If you are using java10 or above you can use orElseThrow() without parameters

You can split the line by the comma , and get an array of values:
try{
BufferedReader reader = new BufferedReader(new FileReader("test.txt"));
String line = reader.readLine();
String data[] = null;
while (line != null){
System.out.println(line);
line = reader.readLine();
data = line.split(","); //data will have the values as an array
}
reader.close();
} catch(IOException ex){
System.out.println(ex.getMessage());
}

If I´m not wrong then the described format is the csv format ( https://en.wikipedia.org/wiki/Comma-separated_values)
Here is good overview how you can read csv data:
https://www.baeldung.com/java-csv-file-array

Java Parsing strings [duplicate]

This question already has answers here:
Parse and read data from a text file [duplicate]
(3 answers)
How to use java.util.Scanner to correctly read user input from System.in and act on it?
(1 answer)
Effective way to read file and parse each line
(3 answers)
parsing each line in text file java
(7 answers)
Closed 5 years ago.
I got .txt file with nationalities and phone numbers in different formats and all these in single quote symbols, also it contains empty lines (''):
''
'French'
'1-500'
'0345134123'
''
''
'German'
etc
after I parse with the help of readLine() I got arr[0] with each of these lines.
I need to put lines into different arrays: lines with 'nationality' into one array and lines with 'phone numbers' into other.
I tried this
if(!arr[0].equals("''")){
String[] arr1 = arr[0].split("'");
if(!arr1[1].matches("[0-9]+)"){
nations[n] = arr1[1];
n++;
}
else {
phone_numbers[p] = arr1[1];
p++;
}
}
Ofcourse it didn't work

In your question you said that you want
to put lines into different arrays: lines with 'nationality' into one array and lines with 'phone numbers' into other.
public static void main(String[] args) {
try{
File file = new File("path\\to\\yourfile");
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
String line = "";
String nationalities = "";
String phones = "";
while((line = br.readLine()) != null){
String[] s = line.split("'");
if(s.length > 0){
if(s[1].matches("[a-zA-Z]+")){
// nationalities
nationalities += (nationalities.isEmpty()) ? s[1] : " " + s[1];
}else{
// line with phone numbers
phones += (phones.isEmpty()) ? s[1] : " " + s[1];
}
}
}
String[] nationArr = nationalities.split(" ");
String[] phoneArr = phones.split(" ");
for(String val : nationArr){
System.out.println(val);
}
System.out.println("------------");
for(String val : phoneArr){
System.out.println(val);
}
}catch(IOException e){
System.out.println("Error");
}
}
I tested with this text file
''
'French'
'1-500'
'0345134123'
''
''
'Japan'
'2-200'
'08078933444'
''
''
''
'Germany'
'2-300'
'00078933444'
''
You will get two array, nationality[nationArr] and line with phone[phoneArr].
Here is the answer.
French
Japan
Germany
------------
1-500
0345134123
2-200
08078933444
2-300
00078933444

I would suggest implementing some sort of system to differentiate between the types of lines. You could put 'n' at the start of the line for nationality, then detect it in your code.... Or if you knew the exact order of these lines e.g. nationality,number,nationality,number... you could easily separate these lines e.g. lineNumber%numOfLineTypes==0 would give you the first type of line...

Why this code skip the first line of file? [duplicate]

This question already has answers here:
Reading UTF-8 - BOM marker
(9 answers)
Closed 5 years ago.
I applied this code more than one, this code is to read a file and for each line, it should create a new object and add it to att_agreement ArrayList, it works fine for each line except the first line, I can not find its object in the output.
Any help, please?
public ArrayList<Att_Elements> load_ann(File f) {
ArrayList<Att_Elements> att_agreement = new ArrayList<Att_Elements>();
String line="";
try {
BufferedReader read = new BufferedReader(new InputStreamReader(new FileInputStream(f), "UTF8"));
while((line = read.readLine()) != null) {
String[] SplitLine = line.split("\\|");
if (SplitLine[0].equals("Att")) {
annotation=new Att_Elements();
annotation.Type = SplitLine[0];
.
.
.
//...
att_agreement.add(annotation);
}
}
read.close();
} catch (IOException e) {
e.printStackTrace();
}
return att_agreement;
}
Here is a sample of file content (3 lines):

Your file likely has what is called a BOM located at the beginning. This is a byte order mark. Thus, your conditional .equals("Att") is not being met until the second line where the BOM is not present. A separate if statement to handle this case should work well. If you print each line read, you should see what the BufferedReader is reading as the first line. The new conditional statement can then be tailored to this value.
Another approach is to search for a generic BOM string and replace it with nothing.

Parsing text Java from PDF [duplicate]

This question already has answers here:
Advanced PDF parser for Java
(5 answers)
Closed 7 years ago.
I would like to ask, how can i parse text. I had extracted text from PDF file with PDFBox into normal text, which is output in console. For example this one:
SHA256: 51c11994540537b633cf91b276b3c34556695ed870a5d3f7451e993262a4a745
File name: ACleaner.zip
Detection ratio: 0 / 55
Analysis date: 2015­07­21 12:23:19 UTC ( 8 minutes ago )
0 0
? Analysis ? File detail ? Additional information ? Comments  0 ? Votes
MD5  fffa183f43766ed39d411cb5f48dbc87
SHA1  b0d40fbc6c722d59031bb488455f89ba086eacd9
SHA256  51c11994540537b633cf91b276b3c34556695ed870a5d3f7451e993262a4a745
I need to get some values, for example value of MD5, File name etc..how can i reach it in Java? Thanks a lot
I have tried so : in this while a i added this
String keySHA256 = "SHA256:";
private static String SHA256Value = null;
if (line.contains(keySHA256)) {
// System.out.println(line);
int length = keySHA256.length();
SHA256Value = line.substring(length);
System.out.println("SHA256 >>>>" + SHA256Value);
}
but sometimes it doesnt get right value..please help..

This could be a good example for you to start learning more about Java IO and String parsing. Google is your friend.
//uri where your file is
String fileName = "c://lines.txt";
// read the file into a buffered reader
try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
String line;
while ((line = br.readLine()) != null) { //iterate on each line of the file
System.out.println(line); // print it if you want
String[] split=line.split(" "); // split your line into array of strings, each one is a separate word that has no spaces in it.
//add any checks or extra processes here
}
} catch (IOException e) {
e.printStackTrace();
}