How To Read A Text File Every Minute String Inwards Java

There was no slow means to read a text file equally String inwards Java until JDK 7, which released NIO 2. This API instantly provides a span of utility methods which you lot tin post away role to read entire file equally String e.g. Files.readAllBytes() returns a byte array of the entire text file. You tin post away convert that byte array to String to convey a whole text file equally String within your Java program. If you lot postulate all lines of files equally List of String e.g. into an ArrayList, you lot tin post away role Files.readAllLines() method. This render a List of String, where each String represents a unmarried trouble of the file. Prior to these API changes, I used to role the BufferedReader together with StringBuilder to read the entire text file equally String. You iterate through the file, reading i trouble at a fourth dimension using readLine() method together with appending them into a StringBuilder until you lot hit the terminate of the file. You tin post away even hence role this method if you lot are running on Java SE vi or lower version.

In this article, we'll hold off at a span of examples to demonstrate how to read a text file equally String, or acquire a List of lines equally String from a text file. I'll likewise demo the BufferedReader way, which you lot tin post away role inwards Java SE vi together with before version.

Reading Text File equally String inwards Java 7

This is the touchstone means to read the whole file equally String inwards Java. Just brand certain the file is a pocket-size or medium size together with you lot convey plenty heap infinite to gibe the text from a file into memory. If you lot don't convey plenty memory, the below code tin post away throw java.lang.OutOfMemoryError: Java heap space, hence beware of that.



Here is the method to read a file equally String inwards Java 7:

public static String readFileAsString(String fileName) {     String text = "";     try {       text = new String(Files.readAllBytes(Paths.get("file.txt")));     } catch (IOException e) {       e.printStackTrace();     }      return text;   }

You should likewise move careful amongst grapheme encoding. Above code assumes that file together with platform's default grapheme encoding is same. If that's non the instance hence role the right grapheme encoding piece converting byte array to String inwards Java. See Core Java Volume 1 - Fundamentals past times Cay S. Horstmann to larn to a greater extent than close grapheme encoding together with converting bytes to text inwards Java.

Reading Text File equally String inwards Java 6

This was the onetime means to reading a file equally String inwards Java. You tin post away come across that it require almost 8 to 10 lines of code, which tin post away instantly effectively move done inwards simply i trouble inwards Java 7. It uses the readLine() method to read the file trouble past times line together with hence joined them together using StringBuilder's append() method.

    BufferedReader br = new BufferedReader(new FileReader("file.txt"));     StringBuilder sb = new StringBuilder();      String trouble = br.readLine();     while (line != null) {       sb.append(line).append("\n");       trouble = br.readLine();     }      String fileAsString = sb.toString();

Don't forget to append the \n grapheme to insert the trouble break, otherwise, all lines volition move joined together together with all text from the file volition come upwards equally simply i big line. If you lot are non familiar amongst \n or \r\n, I advise you lot read Big Java: Early Objects fifth Edition past times Cay S. Horstmann to larn to a greater extent than close special characters inwards Java.

Java Program to read a text file equally String

Here is the consummate Java plan to read a text file equally String, it includes both JDK vi together with JDK vii approach to reading the content of the file inwards a String variable.

import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Paths;  /*  * Java Program read a text file equally String   * commencement past times using the JDK vii utility method Files.readAllBytes()  * together with minute past times using BufferedReader together with StringBuilder.  */  public class ReadFileAsString {    public static void main(String[] args) throws Exception {      // read whole file equally String inwards JDK 7     String data = "";     try {       data = new String(Files.readAllBytes(Paths.get("file.txt")));     } catch (IOException e) {       e.printStackTrace();     }     System.out.println("Text file equally String inwards Java");     System.out.println(data);      // read file equally String inwards Java SE vi together with lower version     BufferedReader br = new BufferedReader(new FileReader("file.txt"));     StringBuilder sb = new StringBuilder();      String trouble = br.readLine();     while (line != null) {       sb.append(line).append("\n");       trouble = br.readLine();     }      String fileAsString = sb.toString();     System.out         .println("whole file equally String using BufferedReader together with StringBuilder");     System.out.println(fileAsString);      br.close();   } }  Output Text file equally String in Java Effective Java is the best mass for senior Developers. Clean code is the best mass for Junior Developers. whole file equally String using BufferedReader and StringBuilder Effective Java is the best mass for senior Developers. Clean code is the best mass for Junior Developers.

In the minute example, don't forget to append the "\n" or "\r\n" depending upon whether you lot are running on Windows or UNIX, otherwise all lines of files are concatenated into simply i line. Also, don't forget to unopen the BufferedReader to forestall resources leak, specially when you lot are non using automatic resources management characteristic of Java 7.


That's all close how to read a text file equally String inwards Java. You tin post away role the novel means if your plan is running on JRE vii together with onetime means if you lot are using Java vi or lower versions. Pay attending to grapheme encoding of the file if you lot are non certain whether both file together with platform's default grapheme encoding (the machine where your Java plan is running) is non same.

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