Develop Reference

Replace defined words in a file with replacements in another file - Java

I have a file (file1.txt) containing:
word word word2 word word1
word2 word word 1
The other file (file2.txt) contains:
word1-replacement1
word2-replacement2
I need a method looking up if the words from file2 are contained in file1 and if they are contained replace those words with the replacement.
I already have following:
BufferedReader br = new BufferedReader(new FileReader("file2.txt"));
BufferedReader br2 = new BufferedReader(new FileReader("file1.txt"));
String line;
String line2;
while ((line = br.readLine()) != null) {
String vars[] = line.split("-");
String varname = vars[0];
String replacement = vars[1];
while ((line2 = br2.readLine()) != null) {
if(line2.contains(varname)) {
line2.replace(varname, replacement);
}
}
}
The problem with this code is, that it just reads only the first line of file1.
The final output should look like:
word word replacement2 word replacement1
replacement2 word replacement1
Thanks for your help :)

I suggest first reading in the second file into Java memory, and storing the data as a key value store in a hashmap. Then, iterate over the lines from the first file, and make any matching replacements.
Map<String, String> map = new HashMap<>();
String line = "";
try (BufferedReader br = new BufferedReader(new FileReader("file2.txt"))) {
while ((line = br.readLine()) != null) {
String[] parts = line.split("-");
map.put(parts[0], parts[1]);
}
}
catch (IOException e) {
// handle exception
}
try (BufferedReader br = new BufferedReader(new FileReader("file1.txt"))) {
while ((line = br.readLine()) != null) {
for (Map.Entry< String, String > entry : map.entrySet()) {
String pattern = "\\b" + entry.getKey() + "\\b";
line = line.replaceAll(pattern, entry.getValue());
// now record the updated line; printed to the console here for demo purposes
System.out.println(line);
}
}
}
catch (IOException e) {
// handle exception
}
Note carefully that I call String#replaceAll above with word boundaries around each term. This matters because, for example, without boundaries the term word1 would match something like aword1term, that is, it would match word1 even as a substring of some other word.

You can start by creating a Map of replacements like so:
public Map<String,String> getReplacements(File file) throws FileNotFoundException {
Map<String, String> replacementMap = new HashMap<>();
Scanner sc = new Scanner(file);
while(sc.hasNextLine()) {
String line = sc.nextLine();
String [] replacement = line.split("-");
String from = replacement[0];
String to = replacement[1];
replacementMap.put(from,to);
}
return replacementMap;
}
And then use the map to replace the words in the other file.

How to remove the duplicate string?

In my code I have two files in my drive those two files have some text and I want to display those string in the console and also remove the repeated string and display the repeated string once rather than displaying it twice.
Code:
public class read {
public static void main(String[] args) {
try{
File file = new File("D:\\file1.txt");
FileReader fileReader = new FileReader(file);
BufferedReader br = new BufferedReader(fileReader);
StringBuffer stringBuffer = new StringBuffer();
String line;
while((line = br.readLine()) != null){
stringBuffer.append(line);
stringBuffer.append("\n");
}
fileReader.close();
System.out.println("Contents of file1:");
String first = stringBuffer.toString();
System.out.println(first);
File file1 = new File("D:\\file2.txt");
FileReader fileReader1 = new FileReader(file1);
BufferedReader br1 = new BufferedReader(fileReader1);
StringBuffer stringBuffer1 = new StringBuffer();
String line1;
while((line1 = br1.readLine()) != null){
stringBuffer1.append(line1);
stringBuffer1.append("\n");
}
fileReader1.close();
System.out.println("Contents of file2:");
String second = stringBuffer1.toString();
System.out.println(second);
System.out.println("answer:");
System.out.println(first+second);
}catch (IOException e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
Output is:
answer:
hi hello
how are you
hi ya
i am fine
But I want to compare both the strings and if the same string repeated then that string should be displayed once.
Output I expect is like this:
answer:
hi hello
how are you
ya
i am fine
Where the "hi" is found in both the strings so that I need to delete the one duplicate string.
How can I do that please help.
Thanks in advance.

You can pass your lines through this method to parse out duplicate words:
// store unique previous words
static Set<String> words = new HashSet<>();
static String removeDuplicateWords(String line) {
StringJoiner sj = new StringJoiner(" ");
// split on whitespace to get distinct words
for (String word : line.split("\\s+")) {
// try to add word to the set
if (words.add(word)) {
// if the word was added (=not seen before), append to the result
sj.add(word);
}
}
return sj.toString();
}

StringTokenizer multiple lines

I have two files, called "ride.in" and "ride.out". The "ride.in" file contains two lines, one containing the string "COMBO" and the other line containing the string "ADEFGA". As I said, each string is on separate lines, so "COMBO" is on the first line, while "ADEFGA" is on the second line in the "ride.in" file.
Here is my code:
public static void main(String[] args) throws IOException {
File in = new File("ride.in");
File out = new File("ride.out");
String line;
in.createNewFile();
out.createNewFile();
BufferedReader br = new BufferedReader(new FileReader(in));
PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(out)));
while ((line = br.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);
String sam =st.nextToken();
}
pw.close();
}
}
I want to assign COMBO as one token and ADEFGA as another token, but in this code, both COMBO and ADEFGA are assigned to the sam string. How do I assign COMBO to one string, and ADEFGA to another string?

You can read each line from the file into a List<String>:
List<String> words = Files.readAllLines(new File("ride.in").toPath(), Charset.defaultCharset() );
Alternatively, you can use Fileutils:
List<String> words = FileUtils.readLines(new File("ride.in"), "utf-8");
words should now contain:
['COMBO', 'ADEFGA']
Note: Adjust your ride.in's file path accordingly

You can't create variable number of variables.
Create a arraylist of string.
Change
while ((line = br.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);
String sam =st.nextToken();
}
to
List<String> myList = new ArrayList<String>();
while ((line = br.readLine()) != null) {
StringTokenizer st = new StringTokenizer(line);
myList.add(st.nextToken());
}
Now myList.get(0) will have "COMBO" and myList.get(1) will have "ADEFGA"

Get specific text from a .txt file

I want to get information from a script so i used this function
public static HashMap<String, String> getEnvVariables(String scriptFile,String config) {
HashMap<String, String> vars = new HashMap<String, String>();
try {
FileInputStream fstream = new FileInputStream(scriptFile);
BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
String strLine;
String var= "if [ \"$1\" = \""+config +"\" ] ; then";
// Read File Line By Line
while ((strLine = br.readLine()) != null) {
// use a Scanner to parse the content of each line
// exclude concatenated variables (export xx:$xx)
if (strLine.startsWith("export") && !strLine.contains("$")) {
strLine = strLine.substring(7);
Scanner scanner = new Scanner(strLine);
scanner.useDelimiter("=");
if (scanner.hasNext()) {
String name = scanner.next();
String value = scanner.next();
System.out.println(name+"="+value);
vars.put(name, value);
}
}
}
However i want to begin reading from a particular line which is
if [ \"$1\" = \""+config +"\" ] ; then
the problem is that when a line begins with a space the program considers that the file have ended !
So how can i fix it and make the program pars to the end of file ?
considering that the line could begin with more thant one space
thx

You may try to trim the irrelevant spaces from every line ?
while ((strLine = br.readLine().trim()) != null) {...}
Edit : don't do that (thanks Joop Eggen!) or you'll have a nice NPE...). Try:
while ((strLine = br.readLine()) != null) {
strLine = strLine.trim();
...
}

Sounds for me like you should use regular expressions (e.g. use the String.matches() method). They also can extract strings or substrings (see: another Stackoverflow article).
There is also an excellent introduction by Lars Vogella about regular expressions in Java. Oracle compiled also a Tutorial/Lesson about that topic.
May be this snippet helps a bit (uses org.apache.commons.io.LineIterator):
public void grepLine(File file, String regex)
{
LineIterator it = FileUtils.lineIterator(file, "UTF-8");
try
{
while (it.hasNext())
{
String line = it.nextLine();
if(line.matches(regex))
{
//...do your stuff
}
}
}
finally
{
LineIterator.closeQuietly(it);
}
}
The regex might be something like (note: havn't checked it - especially the backslashes):
String regex="^\\s*if\\s+\\[\\s+\\\"\\$1\\\" = \\\""+config +"\\\" \\] ; then";

Before all else: leave out DataInputStream, more Java Object specific.
boolean started = false;
while ...
if (!started) {
started = strLine.matches("\\s*...\\s*");
} else {
...
Reg ex \\s* stand for zero or more white-space characters (tab, space).

I found a solution which i share with you .
public static HashMap<String, String> getEnvVariables(String scriptFile ,String config1,String config2) {
HashMap<String, String> vars = new HashMap<String, String>();
BufferedReader br = null;
try {
FileInputStream fstream = new FileInputStream(scriptFile);
br = new BufferedReader(new InputStreamReader(fstream));
String strLine = null;
String stopvar = config2;
String startvar =config1;
String keyword = "set";
do {
if (strLine != null && strLine.contains(startvar)) {
if (strLine.contains(stopvar)) {
return vars;
}
while (strLine != null && !strLine.contains(stopvar)) {
strLine = br.readLine();
if (strLine.trim().startsWith(keyword)&& !strLine.contains("$")) {
strLine = strLine.trim().substring(keyword.length())
.trim();
String[] split = strLine.split("=");
String name = split[0];
String value = split[1];
System.out.println(name + "=" + value);
vars.put(name, value);
}
}
}
} while ((strLine = br.readLine()) != null);
} catch (Exception e) {
Status status = new Status(Status.ERROR, Activator.PLUGIN_ID,
IStatus.ERROR, e.getMessage(), e);
Activator.getDefault().getLog().log(status);
}
return vars;
}
thanks for helping !

Comma-separated records into String Array?

I am trying to read a BufferedReader that reads in a file containing records separated by commas. I would like to split each string (or record) in between two commas, strip the double quotes, and put each of those into an index of a String array. For example:
say I have this line in the file:
("0001", "00203", "82409" (newline)
"0002", "00204", "82500" (newline)
etc.)
I want to put 0001 into a String array[1],
I want 00203 into String array[2],
and so on....
The following code traverses the file, putting all records in column two into String array[2]. This means, after I execute the code below, if I do System.out.println (arr[2]), it will print 00203 and 00204, whereas I would like array[2] to be 00203 and array[5] to be 00204.
Here is my code:
public String[] getArray(String source) {
FileInputStream fileinput = new FileInputStream(source);
GZIPInputStream gzip = new GZIPInputStream(fileinput);
InputStreamReader inputstream = new InputStreamReader(gzip);
BufferedReader bufr = new BufferedReader(inputstream);
String str = null;
String[] arr = null;
while((str = bufr.readLine()) != null) {
arr = str.replace("\"", "").split("\\s*,\\s*");
}
return arr;

Commons CSV was designed for your specific use case. Let's not reinvent the wheel, the code below will result in a GZipped CSV being parsed into fields and lines and seems to be what you're trying to do.
public String[][] getInfo() throws IOException {
final CSVParser parser = new CSVParser(new FileReader(new InputStreamReader(new GZIPInputStream(fileinput)), CSVFormat.DEFAULT.withIgnoreSurroundingSpaces(true));
String[][] result = parser.nextRecord().values();
return result;
}

Few of these modifications should work for you.
public String[] getArray(String source) {
FileInputStream fileinput = new FileInputStream(source);
GZIPInputStream gzip = new GZIPInputStream(fileinput);
InputStreamReader inputstream = new InputStreamReader(gzip);
BufferedReader bufr = new BufferedReader(inputstream);
String str = null;
List<String> numbers = new LinkedList<String>;
while((str = bufr.readLine()) != null) {
String[] localArr = str.split(",");
for(String intString : localArr){
numbers.add(intString.trim());
}
}
return arr;

Have you tried using the scanner class as well as scanner.nextInt(). you do not need to do striping then.
Scanner s = new Scanner(inputstream);
ArrayList<String> list = new ArrayList<String>();
while (s.hasNextInt())
list.add(s.nextInt());
String[] arr = list.toArray(new String[list.size()]);

Not tested:
arr = str.replaceAll("\"", "").replaceAll("(","").replaceAll(")","").split(",");