FAQ: Java How To Read A File?

How do I get Java to read a file?

There are several ways to read a plain text file in Java e.g. you can use FileReader, BufferedReader or Scanner to read a text file. Every utility provides something special e.g. BufferedReader provides buffering of data for fast reading, and Scanner provides parsing ability.

Can you use scanner to read a file in Java?

Scanner is a utility class in java. util package which can parse primitive types and strings using regular expressions. It can read text from any object which implements the Readable interface. We can also construct a Scanner that produces values scanned from the specified file.

How do I read a classpath file?

Place the directory of file ( D:myDir )in CLASSPATH and try below: InputStream in = this. getClass(). getClassLoader().

How do I read properties file?

Test.java

  1. import java.util.*;
  2. import java.io.*;
  3. public class Test {
  4. public static void main(String[] args)throws Exception{
  5. FileReader reader=new FileReader(“db.properties”);
  6. Properties p=new Properties();
  7. p.load(reader);
  8. System.out.println(p.getProperty(“user”));

How do I read a file from FileInputStream?

How to read data from a file using FileInputStream?

  1. int read() − This simply reads data from the current InputStream and returns the read data byte by byte (in integer format).
  2. int read(byte[] b) − This method accepts a byte array as parameter and reads the contents of the current InputStream, to the given array.
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How do you split a string in Java?

Java String split() method with regex and length example

  1. public class SplitExample2{
  2. public static void main(String args[]){
  3. String s1=”welcome to split world”;
  4. System.out.println(“returning words:”);
  5. for(String w:s1.split(“\s”,0)){
  6. System.out.println(w);
  7. }
  8. System.out.println(“returning words:”);

What is Java InputStream file?

A FileInputStream obtains input bytes from a file in a file system. What files are available depends on the host environment. FileInputStream is meant for reading streams of raw bytes such as image data. For reading streams of characters, consider using FileReader.

How do I find the classpath?

package com.javacodegeeks.snippets.core;

  1. public class getClassPath {
  2. public static void main(String[] args) {
  3. // Get class path by using getProperty static method of System class.
  4. String strClassPath = System.getProperty( “java.class.path” );
  5. System.out.println( “Classpath is ” + strClassPath);
  6. } }

How do you set classpath?

GUI:

  1. Select Start.
  2. Go to the Control Panel.
  3. Select System and Security.
  4. Select Advanced System settings.
  5. Click on Environment Variables.
  6. Click on New under System Variables.
  7. Add CLASSPATH as variable name and path of files as a variable value.
  8. Select OK.

How do I add a file to classpath?

Here are some of the ways you can add jar files in classpath of a Java program:

  1. Include the JAR name in CLASSPATH environment variable.
  2. Include name of JAR file in -classpath command line option.
  3. Include the jar name in the Class-Path option in the manifest.
  4. Use Java 6 wildcard option to include multiple JAR.

Where do I put properties file?

You can have two choices of selecting the path,

  1. Open the file containing folder and get the path and save that path in the string with file like, InputStream propertiesStream = Object.class.getResourceAsStream(path + File.seperator + “config.properties”);
  2. Save the file in src path, WorkSpace -> Project Name -> Copyhere.
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How do you create a properties file?

Create a properties file Right-click and select Add New Properties File. A new properties file will be added to your project. The new file will be selected and highlighted in the list. Type a name for your properties file, for example, “Properties”.

What is a property file in Java?

properties is a file extension for files mainly used in Java-related technologies to store the configurable parameters of an application. They can also be used for storing strings for Internationalization and localization; these are known as Property Resource Bundles.

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