Java: How to convert a File object to a String object in java? [duplicate]

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Closed 13 years ago.

Possible Duplicate:
How to create a Java String from the contents of a file

I have a html file which I want to use to extract information. For that I am using Jsoup. Now for using Jsoup, I need to convert the html file into a string. How can I do that?

File myhtml = new File("D:\\path\\report.html")';

Now, I want a String object that contains the content inside the html file.

• Mikita Belahlazau: Check this: stackoverflow.com/questions/326390/…
• Thorbjørn Ravn Andersen: Read the file character by character and put each character in a StringBuffer. When done ask the StringBuffer for the string.
• Mikita Belahlazau: Check jsoup api. It has parse method that takes file. You don't need to read file content manually.

Answer 1

I use apache common IO to read a text file into a single string

String str = FileUtils.readFileToString(file);

simple and "clean". you can even set encoding of the text file with no hassle.

String str = FileUtils.readFileToString(file, "UTF-8");

• Nida Sahar: How would you do the opposite... readStringToFile
• Wanna Coffee: Attached link is expired, can you please post latest URL?
• Michael Rountree: FileUtils.readFileToString is now deprecated with Java 8. It is no longer recommended to use this way.

Answer 2

Use a library like Guava or Commons / IO. They have oneliner methods.

Guava:

Files.toString(file, charset);

Commons / IO:

FileUtils.readFileToString(file, charset);

Without such a library, I'd write a helper method, something like this:

public String readFile(File file, Charset charset) throws IOException {
 return new String(Files.readAllBytes(file.toPath()), charset);
}

• Dmytro Chasovskyi: Files.toString is @Deprecated, so the modern way in Guava call Files.asCharSource(file, charset).read().
• Sean Patrick Floyd: @DmytroChasovskyi yep. impossible to keep up with Guava's deprecation cycle, thanks

Answer 3

With Java 7, it's as simple as:

final String EoL = System.getProperty("line.separator");
List<String> lines = Files.readAllLines(Paths.get(fileName),
 Charset.defaultCharset());
StringBuilder sb = new StringBuilder();
for (String line : lines) {
 sb.append(line).append(EoL);
}
final String content = sb.toString();

However, it does havea few minor caveats (like handling files that does not fit into the memory).

I would suggest taking a look on corresponding section in the official Java tutorial (that's also the case if you have a prior Java).

As others pointed out, you might find sime 3rd party libraries useful (like Apache commons I/O or Guava).

Answer 4

Readin file with file inputstream and append file content to string.

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
public class CopyOffileInputStream {
 public static void main(String[] args) {
 //File file = new File("./store/robots.txt");
 File file = new File("swingloggingsscce.log");
 FileInputStream fis = null;
 String str = "";
 try {
 fis = new FileInputStream(file);
 int content;
 while ((content = fis.read()) != -1) {
 // convert to char and display it
 str += (char) content;
 }
 System.out.println("After reading file");
 System.out.println(str);
 } catch (IOException e) {
 e.printStackTrace();
 } finally {
 try {
 if (fis != null)
 fis.close();
 } catch (IOException ex) {
 ex.printStackTrace();
 }
 }
 }
}

Answer 5

By the way, Jsoup has method that takes file: http://jsoup.org/apidocs/org/jsoup/Jsoup.html#parse(java.io.File,%20java.lang.String)

Answer 6

You can copy all contents of myhtml to String as follows:

Scanner myScanner = null;
try
{
 myScanner = new Scanner(myhtml);
 String contents = myScanner.useDelimiter("\\Z").next(); 
}
finally
{
 if(myScanner != null)
 {
 myScanner.close(); 
 }
}

Ofcourse, you can add a catch block to handle exceptions properly.

Answer 7

Why you just not read the File line by line and add it to a StringBuffer?

After you reach end of File you can get the String from the StringBuffer.