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Java: Searching for specific word in a text file

I've currently got a large text file with lots of the most popular names. I get the user to input a specific name and I'm currently trying to print the line that has the name. My problem is that if the user enters a name like Alex, every name that contains Alex like Alexander, Alexis, Alexia gets printed when I only want Alex to get printed. What can I do to "if(line.contains(name)){" to fix this.
The line contains info like the name, it's popularity ranking and number of people with that name
try {
line = reader.readLine();
while (line != null) {
if(line.contains(name)){
text += line;
line = reader.readLine();
}
line = reader.readLine();
}
}catch(Exception e){
System.out.println("Error");
}
System.out.println(text);

A shorthand would be to use Java8 Streams: Here is a look :
public class Test2 {
public static void main(String[] args) {
String fileName = "c://lines.txt";
String name = "nametosearch";
try (Stream<String> stream = Files.lines(Paths.get(fileName))) {
stream.filter(line -> line.contains(" " + name + " ")).forEach(System.out::println);
} catch (IOException e) {
e.printStackTrace();
}
}
}

You can use regex with a word boundary for this task:
final String regex = String.format("\\b%s\\b", name);
final Pattern pattern = Pattern.compile(regex);
final Matcher matcher = pattern.matcher(line);
matcher.find();
if( matcher.group(0).length() > 0 ) {
text += line;
line = reader.readLine();
}

line.equals(name)
Replace
line.contains(name)

Buffer Reader code to read input file

I have a text file named "message.txt" which is read using Buffer Reader. Each line of the text file contains both "word" and "meaning" as given in this example:
"PS:Primary school"
where PS - word, Primary school - meaning
When the file is being read, each line is tokenized to "word" and "meaning" from ":".
If the "meaning" is equal to the given input string called "f_msg3", "f_msg3" is displayed on the text view called "txtView". Otherwise, it displays "f_msg" on the text view.
But the "if condition" is not working properly in this code. For example if "f_msg3" is equal to "Primary school", the output on the text view must be "Primary school". But it gives the output as "f_msg" but not "f_msg3". ("f_msg3" does not contain any unnecessary strings.)
Can someone explain where I have gone wrong?
try {
BufferedReader file = new BufferedReader(new InputStreamReader(getAssets().open("message.txt")));
String line = "";
while ((line = file.readLine()) != null) {
try {
/*separate the line into two strings at the ":" */
StringTokenizer tokens = new StringTokenizer(line, ":");
String word = tokens.nextToken();
String meaning = tokens.nextToken();
/*compare the given input with the meaning of the read line */
if(meaning.equalsIgnoreCase(f_msg3)) {
txtView.setText(f_msg3);
} else {
txtView.setText(f_msg);
}
} catch (Exception e) {
txtView.setText("Cannot break");
}
}
} catch (IOException e) {
txtView.setText("File not found");
}

Try this
............
meaning = meaning.replaceAll("\\s+", " ");
/*compare the given input with the meaning of the read line */
if(meaning.equalsIgnoreCase(f_msg3)) {
txtView.setText(f_msg3);
} else {
txtView.setText(f_msg);
}
............
Otherwise comment the else part, then it will work.

I don't see any obvious error in your code, maybe it is just a matter
of cleaning the string (i.e. removing heading and trailing spaces, newlines and so on) before comparing it.
Try trimming meaning, e.g. like this :
...
String meaning = tokens.nextToken();
if(meaning != null) {
meaning = meaning.trim();
}
if(f_msg3.equalsIgnoreCase(meaning)) {
txtView.setText(f_msg3);
} else {
txtView.setText(f_msg);
}
...

A StringTokenizer takes care of numbers (the cause for your error) and other "tokens" - so might be considered to invoke too much complexity.
String[] pair = line.split("\\s*\\:\\s*", 2);
if (pair.length == 2) {
String word = pair[0];
String meaning = pair[1];
...
}
This splits the line into at most 2 parts (second optional parameter) using a regular expression. \s* stands for any whitespace: tabs and spaces.
You could also load all in a Properties. In a properties file the format key=value is convention, but also key:value is allowed. However then some escaping might be needed.

ArrayList vals = new ArrayList();
String jmeno = "Adam";
vals.add("Honza");
vals.add("Petr");
vals.add("Jan");
if(!(vals.contains(jmeno))){
vals.add(jmeno);
}else{
System.out.println("Adam je už v seznamu");
}
for (String jmena : vals){
System.out.println(jmena);
}
try (BufferedReader br = new BufferedReader(new FileReader("dokument.txt")))
{
String aktualni = br.readLine();
int pocetPruchodu = 0;
while (aktualni != null)
{
String[] znak = aktualni.split(";");
System.out.println(znak[pocetPruchodu] + " " +znak[pocetPruchodu + 1]);
aktualni = br.readLine();
}
br.close();
}
catch (IOException e)
{
System.out.println("Nezdařilo se");
}
try (BufferedWriter bw = new BufferedWriter(new FileWriter("dokument2.txt")))
{
int pocetpr = 0;
while (pocetpr < vals.size())
{
bw.write(vals.get(pocetpr));
bw.append(" ");
pocetpr++;
}
bw.close();
}
catch (IOException e)
{
System.out.println("Nezdařilo se");
}

java string matching from a large text file issue

I would like to implement a task of string matching from a large text file.
1. replace all the non-alphanumeric characters
2. count the number of a specific term in the text file. For example, matching term "tom". The matching is not case sensitive.so term "Tom" should me counted. However the term tomorrow should not be counted.
code template one:
try {
in = new BufferedReader(new InputStreamReader(new FileInputStream(inputFile));
} catch (FileNotFoundException e1) {
System.out.println("Not found the text file: "+inputFile);
}
Scanner scanner = null;
try {
while (( line = in.readLine())!=null){
String newline=line.replaceAll("[^a-zA-Z0-9\\s]", " ").toLowerCase();
scanner = new Scanner(newline);
while (scanner.hasNext()){
String term = scanner.next();
if (term.equalsIgnoreCase(args[1]))
countstr++;
}
}
} catch (IOException e) {
e.printStackTrace();
}
code template two:
try {
in = new BufferedReader(new InputStreamReader(new FileInputStream(inputFile));
} catch (FileNotFoundException e1) {
System.out.println("Not found the text file: "+inputFile);
}
Scanner scanner = null;
try {
while (( line = in.readLine())!=null){
String newline=line.replaceAll("[^a-zA-Z0-9\\s]", " ").toLowerCase();
String[] strArray=newline.split(" ");//split by blank space
for (int =0;i<strArray.length;i++)
if (strArray[i].equalsIgnoreCase(args[1]))
countstr++;
}
}
} catch (IOException e) {
e.printStackTrace();
}
By running the two codes, I get the different results, the Scanner looks like to get the right one.But for the large text file, the Scanner runs much more slower than the latter one. Anyone who can tell me the reason and give a much more efficient solution.

In your first approch. You dont need to use two scanner. Scanner with "" is not good choice for the large line.
your line is already Converted to lowercase. So you just need to do lowercase of key outside once . And do equals in loop
Or get the line
String key = String.valueOf(".*?\\b" + "Tom".toLowerCase() + "\\b.*?");
Pattern p = Pattern.compile(key);
word = word.toLowerCase().replaceAll("[^a-zA-Z0-9\\s]", "");
Matcher m = p.matcher(word);
if (m.find()) {
countstr++;
}
Personally i would choose BufferedReader approach for the large file.
String key = String.valueOf(".*?\\b" + args[0].toLowerCase() + "\\b.*?");
Pattern p = Pattern.compile(key);
try (final BufferedReader br = Files.newBufferedReader(inputFile,
StandardCharsets.UTF_8)) {
for (String line; (line = br.readLine()) != null;) {
// processing the line.
line = line.toLowerCase().replaceAll("[^a-zA-Z0-9\\s]", "");
Matcher m = p.matcher(line);
if (m.find()) {
countstr++;
}
}
}
Gave Sample in Java 7. Change if required!!

Regex in Java is not matching anything from text file

I have a text file with several lines
Category: Type of problem you're having
Description: Overview of the problem
How To Fix: Directions to fix your problem (has carriage
returns, sometimes)
Related Links: Additional Resources
**There are no numbers in my list; it was the only way I could think of to make it neater...*
I've been trying to get my code to recognize all of the information between "How To Fix:" and "Related Links" when it has more than one line. I know from my research that I have to use either (?s) or Pattern.DOTALL, however neither of them seem to be working. I'm fairly new to Regex, so I'm expect is something elementary. Here is my code:
String fileName = System.getProperty("user.home") + "/Desktop/Test.txt";
try {
FileReader fr = new FileReader(fileName);
BufferedReader br = new BufferedReader(fr);
sc1 = new Scanner(br);
String findingRegex = "(Description:.*)";
String recommRegex = "(?<=How To Fix:)(.*)(?=Related Links)";//regex I'm trying to use
Pattern pFinding = Pattern.compile(findingRegex);
Pattern pRecomm = Pattern.compile(recommRegex, Pattern.DOTALL);
while (sc1.hasNextLine()) {
String clean = sc1.nextLine().trim();
String clean2 = clean.replaceAll("\\\\x\\p{XDigit}{2}", "");
Matcher mFinding = pFinding.matcher(clean2);
Matcher mRecomm = pRecomm.matcher(clean2);
while (mFinding.find()) {
System.out.println(mFinding);
}
while (mRecomm.find()){
System.out.println(mRecomm); //nothing prints?
}
}
br.close();
fr.close();
System.out.println("The following data was imported: ");
try {
tbl.displayAll();
} catch (NullPointerException npe) {
System.out.println("You have no data.");
}
} catch (FileNotFoundException fnfe) {
System.out.println("File named Test.txt was not located on your desktop. Program Terminated.");
System.exit(0);
} catch (IOException ioe) {
System.out.println("The import operation failed. Program Terminated");
System.exit(0);
} finally {
sc1.close();
}
Lastly, I tested my Regex here and it worked as expected?
MY SOLUTION:
String findingRegex = "(?<=Description:)(.*)(?=How To Fix)";
String recommRegex = "(?<=How To Fix:)(.*)(?=Related Links)";
Pattern pFinding = Pattern.compile(findingRegex, Pattern.DOTALL);
Pattern pRecomm = Pattern.compile(recommRegex, Pattern.DOTALL);
StringBuilder sb = new StringBuilder();
String line = br.readLine();
while (line != null){
sb.append(line);
sb.append(System.lineSeparator());
line = br.readLine();
}
String newFile = sb.toString();
Matcher mFinding = pFinding.matcher(newFile);
Matcher mRecomm = pRecomm.matcher(newFile);
while (mFinding.find()) {
System.out.println(mFinding);
}
while (mRecomm.find()){
System.out.println(mRecomm);
}

Here:
String clean = sc1.nextLine().trim();
You are breaking your input up by line. But then you're trying to match multiple lines. There aren't multiple lines to match, because you only kept the one.
You could read the entire file into memory first, and then match against it. Or you could do something like
StringBuilder sb = new StringBuilder();
int state = 0;
while (sc1.hasNextLine()) {
String line = sc1.nextLine();
if (line.contains("How To Fix:")) {
state = 1;
}
if (state == 1) {
sb.append(line);
}
if (line.contains("Related Links:")) {
state = 0;
}
}
(You'll need to modify this if you need to match more than once per file.)

Any url that starts with the pattern.. do this

I want to compare url A (http://www.somehost.com/citizenship) with the pattern url B (http://www.somehost.com/*) and if that URL A starts with the pattern url B then do this thing.. As URL A is originated from the URL B.. So any url that starts with this pattern.. just do this thing in the if loop... Any suggestions will be appreciated...!!
BufferedReader readbuffer = null;
try {
readbuffer = new BufferedReader(new FileReader("filters.txt"));
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
String strRead;
try {
while ((strRead=readbuffer.readLine())!=null){
String splitarray[] = strRead.split(",");
String firstentry = splitarray[0];
String secondentry = splitarray[1];
String thirdentry = splitarray[2];
//String fourthentry = splitarray[3];
//String fifthentry = splitarray[4];
System.out.println(firstentry + " " + secondentry+ " " +thirdentry);
URL url1 = new URL("http://www.somehost.com/citizenship");
//Any url that starts with this pattern then do whatever you want in the if loop... How can we implement this??
Pattern p = Pattern.compile("http://www.somehost.com/*");
Matcher m = p.matcher(url1.toString());
if (m.matches()) {
//Do whatever
System.out.println("Yes Done");
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

What's wrong with String.startsWith(String)?
You could invoke it like this: url1.toString().startsWith("http://www.somehost.com/").
Or did I miss what you're exactly trying to achieve?
Anyways, this is the regular expression to build: http://www\.somehost\.com/.*
You need to learn regular expression syntax, in which "." mean any character so you need to escape it in between "www" and "somehost".
In Java code, you need to escape backspaces as well hence it becomes: Pattern.compile("http://www\\.somehost\\.com/.*");

I believe this should do the trick:
private final static String regexPattern = "http://www.somehost.com/[0-9a-zA-Z\\-]*/wireless-reach(/[0-9a-zA-Z\\-]*)*";
String pattern = "http://www.somehost.com/citizen-ship/wireless-reach/fil1";
if(pattern.matches(regex))
System.out.println("Matched!");