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Get the list of all URLs on the website using Java [closed]

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There are many libraries(eg. Jsoup) which can do this task in a go but how can I get all the URLs present in the HTML content of any website using Java without using any external libraries?
Edit 1: Can anyone explain what scanner.useDelimiter("\Z") actually does and what is the difference between scanner.useDelimiter("\Z") and scanner.useDelimiter("\z").

I am answering my own question as I was trying to find the accurate answer on StackOverflow but couldn't find one.
Here is the code:
URL url;
ArrayList<String> finalResult = new ArrayList<String>();
try {
String content = null;
URLConnection connection = null;
try {
connection = new URL("https://yahoo.com").openConnection();
Scanner scanner = new Scanner(connection.getInputStream());
scanner.useDelimiter("\\Z");
content = scanner.next();
scanner.close();
} catch (Exception ex) {
ex.printStackTrace();
}
String regex = "(https?|ftp|file)://[-a-zA-Z0-9+&##/%?=~_|!:,.;]*[-a-zA-Z0-9+&##/%=~_|]";
Pattern p = Pattern.compile(regex);
Matcher m = p.matcher(content);
while (m.find()) {
if(!finalResult.contains((m.group())))
finalResult.add(m.group());
}
} finally {
for(String res: finalResult){
System.out.println(res);
}
}

You can try using a regEx.
Here is an example of a regEx that checks if any test is a URL or not.
https://www.regextester.com/96504.
But I can't stop my self to say that Jsoup is what fits for this. but it's an external library.

Searching for a sentence in a file java [closed]

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I am really stuck up with this.
I am having an input file say input.txt.
content of input.txt is
Using a musical analogy, hardware is like a musical instrument and software is like the notes played on that instrument.
Now I want to search the text
like a musical instrument
How can I search the above content in input.txt in java. Any help???

Inorder to search a pattern in java, java provides contains() method in String. Try to use that, Following is the snippet of the code that serve the purpose,
public static void main(String[] args) throws IOException {
FileReader reader = new FileReader(new File("sat.txt"));
BufferedReader br = new BufferedReader(reader);
String s = null;
while((s = br.readLine()) != null) {
if(s.contains("like a musical instrument")) {
System.out.println("String found");
return;
}
}
System.out.println("String not found");
}

You can always use the String#contains() method to search for substrings. Here, we will read each line in the file one by one, and check for a string match. If a match is found, we will stop reading the file and print Match is found!
package com.adi.search.string;
import java.io.*;
import java.util.*;
public class SearchString {
public static void main(String[] args) {
String inputFileName = "input.txt";
String matchString = "like a musical instrument";
boolean matchFound = false;
try(Scanner scanner = new Scanner(new FileInputStream(inputFileName))) {
while(scanner.hasNextLine()) {
if(scanner.nextLine().contains(matchString)) {
matchFound = true;
break;
}
}
} catch(IOException exception) {
exception.printStackTrace();
}
if(matchFound)
System.out.println("Match is found!");
else
System.out.println("Match not found!");
}
}

unreported exception filenotfoundexception [closed]

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I am trying to make a stream, so I can read 2 lines from .txt file to two string variables. I tried try/catch, but still have an ureported exception error.
public class Shad1 {
public void myMethod()throws FileNotFoundException {
String stringName = new String("");
String stringNumb = new String("");
File file = new File ("c:\\input.txt");
try {
DataInputStream input = new DataInputStream(new FileInputStream(file));
int check = input.read();
char data = input.readChar();
while(data != '\n') {
stringName = stringName + data;
}
while (check != -1){
stringNumb = stringNumb + data;}
input.close();
} catch (FileNotFoundException fnfe){System.out.println(fnfe.getMessage());}
}

you're using the read method: note that this method can also throw an IOException. See the docs for the read method here, the declaration is:
public final int read(byte[] b) throws IOException
So you'll also need to catch IOException, or report that your method throws IOException.
Note that you don't need to do both, so in your example code, you can similarly choose to report that your method throws FileNotFoundException or declare it in a catch block: you don't need both (unless some other part of the code in the method might generate an unhandled FileNotFoundException).

How to read a file, Split the contents and print it? [closed]

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i have a file named "file" which is a text file(the file contains 1,2,3,4 integers).. Now i want to read this file and split the values in the file and print each value in new line. How can i do that??

Try this:
public static void main( String args[] )
{
try {
Scanner sc = new Scanner(new File("number.txt"));
sc.useDelimiter(",");
while (sc.hasNextInt()) {
System.out.println(sc.nextInt());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}

public class Main {
public static void main(String[] str) throws Exception{
File f = new File("C:\\prince\\temp\\test.txt");
FileInputStream fis = new FileInputStream(f);
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String line = null;
while ((line = br.readLine()) != null) {
String[] splitedTokens = line.split("[,]");
for (String splitedToke : splitedTokens) {
System.out.println(splitedToke);
}
}
}
}

Reading string data from file [closed]

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I want to read string data from file and has to pass each strings in the file for some operation.For ex if my file possess links of a website then I have to extract each link and parse its data.I have already done parsing for sites by passing URL as input.But now I think its favorable to store entire links as string and pass it as argument.So how can I read URL from a file and parse each URL data?Can any one specify the code for doing this?

Assuming your file contains a url on each line do this:
BufferedReader br = new BufferedReader(new FileReader(file));
String line;
while((line = br.readLine()) != null) {
// do something with line.
}
But you should be more specific in your question. Where is the problem?

This was your code that I read from your comment:
File file = new File("myfil");
try (FileInputStream fis = new FileInputStream(file)) {
int content; while ((content = fis.read()) != -1) { // convert to char and display it
System.out.print((char) content); }
This is that mess fixed up:
File file = new File("myfil");
String fileContent = ""; // String to keep track of file content
try {
FileInputStream fis = new FileInputStream(file);
int content;
while ((content = fis.read()) != -1)
{
fileContent += (char)content; // append this to the file content as char
}
} catch (IOException e) {
System.out.print("Problem reading file");
}
System.out.print(fileContent); // print it
Keep in mind, you will have to import some stuff into your project. These are the import lines, if you don't already have them:
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

If you don't wan't to write code at all, just use the FileUtils-class.
import org.apache.commons.io.FileUtils;
...
public void yourMethod() {
List<String> lines = FileUtils.readLines(yourFile);
}

You can use regular expression for get list with all url's of your file and later iterate list for do something.
This is a sample example.
public class GetURL {
public static void extractUrls(String input, List<URL> allUrls)
throws MalformedURLException {
Pattern pattern = Pattern
.compile("\\b(((ht|f)tp(s?)\\:\\/\\/|~\\/|\\/)|www.)"
+ "(\\w+:\\w+#)?(([-\\w]+\\.)+(com|org|net|gov"
+ "|mil|biz|info|mobi|name|aero|jobs|museum"
+ "|travel|[a-z]{2}))(:[\\d]{1,5})?"
+ "(((\\/([-\\w~!$+|.,=]|%[a-f\\d]{2})+)+|\\/)+|\\?|#)?"
+ "((\\?([-\\w~!$+|.,*:]|%[a-f\\d{2}])+=?"
+ "([-\\w~!$+|.,*:=]|%[a-f\\d]{2})*)"
+ "(&(?:[-\\w~!$+|.,*:]|%[a-f\\d{2}])+=?"
+ "([-\\w~!$+|.,*:=]|%[a-f\\d]{2})*)*)*"
+ "(#([-\\w~!$+|.,*:=]|%[a-f\\d]{2})*)?\\b");
Matcher matcher = pattern.matcher(input);
while (matcher.find()) {
allUrls.add(new URL(matcher.group()));
}
}
public static void main(String[] args) throws IOException {
List<URL> allUrls = new ArrayList<URL>();
BufferedReader br = new BufferedReader(new FileReader("./urls.txt"));
String line;
while ((line = br.readLine()) != null) {
extractUrls(line, allUrls);
}
Iterator<URL> it = allUrls.iterator();
while (it.hasNext()) {
//Do something
System.out.println(it.next().toString());
}
}
}
Take a look at Apache Commons FileUtils and method readFileToString(File source) for convert directly file to String.