Tutorial Playlist
191 Lessons1. Introduction to Java
2. What is Java?
3. History of Java
4. Java Tutorial for Beginners
5. How Do Java Programs Work?
6. JDK in Java
7. C++ Vs Java
8. Java vs. Python
9. Java vs. JavaScript
10. From Java Source Code to Executable
11. How to Install Java in Linux
12. How to Install Java in Windows 10
13. Java Hello World Program
14. Structure of Java Program and Java Syntax
15. Operators in Java
16. Java If-else
17. Switch Case In Java
18. Loops in Java
19. Infinite loop in Java
20. For Loop in Java
21. For Each Loop in Java
22. Constructor in Java
23. Constructor Overloading in Java
24. Copy Constructor in Java
25. Default Constructor in Java
26. Parameterized Constructors in Java
27. Constructor Chaining In Java
28. Finalize Method in Java
29. Static Method in Java
30. Equals Method in Java
31. Abstract Method in Java
32. toString() Method in Java
33. Difference between equals method in Java
34. Inheritance in Java
35. Multiple Inheritance in Java
36. Hierarchical Inheritance in Java
37. Java Classes and Objects
38. Scanner Class in java
39. All classes in java are inherited from which class
40. What is Nested Class in Java
41. POJO Class in Java
42. Anonymous Class in Java
43. Final Class in Java
44. Object Class in Java
45. Packages in Java
46. Access Modifiers in Java
47. Static Keyword In Java
48. Final Keyword in Java
49. Checked and Unchecked Exceptions in Java
50. User Defined Exception in Java
51. Error vs. Exception in Java
52. Java Collection
53. Collections in Java
54. Garbage Collection in Java
55. Generics In Java
56. Java Interfaces
57. Functional Interface in Java
58. Marker Interface in Java
59. Streams in Java
60. Byte stream in java
61. File Handling in Java
62. Thread in Java
63. Thread Lifecycle In Java
64. Daemon Thread in Java
65. Thread Priority in Java
66. Deadlock in Java
67. String Pool in Java
68. Java Database Connectivity(JDBC)
69. Design Patterns in Java
70. Functional Programming in Java
71. OOP vs Functional vs Procedural
72. Heap Memory and Stack Memory in Java
73. Applet in Java
74. Java Swing
75. Java Frameworks
76. Hibernate Framework
77. JUnit Testing
78. How to Install Eclipse IDE for Java?
79. Command line arguments in Java
80. Jar file in Java
81. Java Clean Code
82. OOPs Concepts in Java
83. Java OOPs Concepts
84. Overloading vs Overriding in Java
85. Java 8 features
86. String in Java
87. String to int in Java
88. Why String Is Immutable in Java?
89. Primitive Data Types in Java
90. Non-Primitive Data Types in Java
91. This and Super Keyword in Java
92. HashMap in Java
93. Comparable And Comparator in Java
94. Type Casting in Java
95. Arrays Sort in Java with Examples
96. Variable Hiding and Variable Shadowing in Java
97. Enum in Java
98. Substring in Java
99. Pattern Programs in Java
100. Hashcode in Java
101. What is ByteCode in Java?
102. How To Take Input From User in Java
103. GCD of Two Numbers in Java
104. Linked List in Java
105. Arithmetic Operators in Java
106. Conditional Operators in Java
107. Stack and Queue in Java
108. Array Length in Java
109. Number Pattern Program in Java
110. Split in java
111. Map In Java
112. Difference Between Throw and Throws in Java
113. Difference Between Data Hiding and Abstraction
114. HashSet in Java
115. String Length in Java
116. Factorial Using Recursion in Java
117. DateFormat in Java
118. StringBuilder Class in java
119. Instance variables in Java
120. Java List Size
121. Java APIs
122. Reverse an Array in Java
123. StringBuffer and StringBuilder Difference in Java
124. Java Program to Add Two Numbers
125. String to Array in Java
126. Regular Expressions in Java
127. Identifiers in Java
128. Data Structures in Java
129. Set in Java
130. Pass By Value and Call By Reference in Java
131. Try Catch in Java
132. Bubble Sort in Java
133. Caesar Cipher Program in Java
134. Queue in Java
135. Object Creation in Java
136. Multidimensional Array in Java
137. How to Read a File in Java
Now Reading
138. String Comparison in Java
139. Volatile Keyword in Java
140. Control Statements in Java
141. Jagged Array in Java
142. Two-Dimensional Array in Java
143. Java String Format
144. Replace in Java
145. charAt() in Java
146. CompareTo in Java
147. Matrix Multiplication in Java
148. Static Variable in Java
149. Event Handling in Java
150. parseInt in Java
151. Java ArrayList forEach
152. Abstraction in Java
153. String Input in Java
154. Logical Operators in Java
155. instanceof in Java
156. Math Floor in Java
157. Selection Sort Java
158. int to char in Java
159. Stringtokenizer in java
160. Implementing and Manipulating Abs in Java
161. Char array to string in java
162. Convert Double To String In Java
163. Deque in Java
164. Converting a List to an Array in Java
165. The Max function in java
166. Removing whitespace from string in java
167. String arrays in Java
168. Strings in Java Vs Strings in Cpp
169. Sum of digits of a number in Java
170. Art of Graphical User Interfaces
171. Trim in Java
172. RxJava
173. Recursion in Java
174. HashSet Java
175. Difference Between Java and Python
176. Square Root in Java
177. Reverse A String in Java
178. Even Odd Program in Java
179. Fibonacci Series in Java
180. Prime Number Program in Java
181. Java Program to Print Prime Numbers in a Given Range
182. Java Leap Year Program
183. Swapping of Two Numbers in Java
184. LCM of Two Numbers in Java
185. Math.sqrt() Function in Java
186. Area of Triangle in Java
187. Sort a String In Java
188. Factorial Program in Java
189. Javafx
190. Lambda expression in java
191. Setup Java Home and IDE on macOS
A frequent operation in many Java programs is reading a file. Understanding how to read a file in Java is crucial whether you need to analyze data from a text file, parse a configuration file, or read a log file. Efficient file reading and handling are crucial for extracting information, performing data analysis, or implementing file-based operations. The numerous approaches and methods for reading text files in Java will be thoroughly discussed in this blog article, giving you a thorough overview of your options. You will have the expertise necessary at the conclusion of this tutorial to successfully handle file reader Java duties in your projects, guaranteeing efficient data retrieval and manipulation.
We will give a succinct review of the various Java methods for reading text files. We will examine traditional and modern approaches, emphasizing their salient traits and advantages. Through examples, explanations, and possible visual aids, we will delve into methods such as the FileReader class, stream-based methods using the Files class, the BufferedReader class, and the Scanner class. By understanding these various techniques, developers will gain a solid foundation in file reading, enabling them to efficiently process data, extract information, and perform analysis in Java applications.
Below mentioned are various types on how to read a text file in Java:
One of the conventional ways of pursuing a record in Java is by utilizing the FileReader class. The FileReader class is essential for the java.io package and gives advantageous strategies for pursuing character files. Let's explore the FileReader class in more detail.
You should import the java.io package and make an example of the FileReader class to use it. You may declare the FileReader class as follows:
import java.io.FileReader;
FileReader reader=new FileReader("path/to/file.txt");
The FileReader class provides several constructors to create an instance. A file path or a File object can be utilized to instate a FileReader object. Here are a few illustrations:
FileReader reader1=new FileReader("path/to/file.txt");
FileReader reader2=new FileReader(new File("path/to/file.txt"));
Whenever you have made a FileReader object, you can utilize its methods to peruse the items in a document. The two most normally utilized methods are 'read()' and 'close()'. The 'read()' method reads a single character from the record and the 'close()' method shuts the FileReader object. Here is a model:
int character = reader.read();
while (character != -1) {
// Process the character
// ...
character = reader.read();
}
reader.close();
We should assemble all that and see an illustration of how to read a record utilizing the FileReader class:
import java.io.FileReader;
import java.io.IOException;
public class FileReaderExample {
public static void main(String[] args) {
try {
FileReader reader = new FileReader("path/to/file.txt");
int character = reader.read();
while (character != -1) {
System.out.print((char) character);
character = reader.read();
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
A stream is a collection of data pieces that may be handled sequentially or concurrently in Java. Reading data from multiple sources, including files, is made simple by streams. They offer a uniform API for reading data while abstracting the underlying I/O activities.
Now, let's explore the different ways to read a file in Java using streams. We will cover the following methods:
Method 1: Reading a file using the Files.lines() function
Method 2: Reading a file using the Files.readString() function
Method 3: Reading a file using the Files.readAllBytes() function
Method 4: Reading a file using the Files.readAllLines() function
Method 5: Reading a file using the BufferedReader class
Method 6: Reading a file using the Scanner class
The Files.lines() function reads all lines from a file and returns a Stream of lines. You can use the Stream API to process the lines further. Here is an example:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;
public class ReadFileExample {
public static void main(String[] args) {
String filePath = "path/to/file.txt";
try (Stream<String> lines = Files.lines(Paths.get(filePath))) {
lines.forEach(System.out::println);
} catch (IOException e) {
e.printStackTrace();
}
}
}
The Files.readString() function reads all the content from a document and returns it as a String. This method is helpful when you really want to read the whole record as a single String. Here is a model:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class ReadFileExample {
public static void main(String[] args) {
String filePath = "path/to/file.txt";
try {
String content = Files.readString(Paths.get(filePath));
System.out.println(content);
} catch (IOException e) {
e.printStackTrace();
}
}
}
The function Files.readAllBytes() peruses all bytes from a document and returns them as a byte array. This approach is suitable for perusing binary files or handling data at a lower level. Here is an illustration:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class ReadFileExample {
public static void main(String[] args) {
String filePath = "path/to/file.txt";
try {
byte[] bytes = Files.readAllBytes(Paths.get(filePath));
// Process the byte array
} catch (IOException e) {
e.printStackTrace();
}
}
}
A list of Strings is returned as a result of the Files.readAllLines() method reading every line from a file. Like Files.lines(), this function returns the lines as a Rundown instead of a Stream. Here's an illustration:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
public class ReadFileExample {
public static void main(String[] args) {
String filePath = "path/to/file.txt";
try {
List<String> lines = Files.readAllLines(Paths.get(filePath));
lines.forEach(System.out::println);
} catch (IOException e) {
e.printStackTrace();
}
}
}
The BufferedReader class provides efficient reading of characters from a file. It buffers the input and reduces the number of I/O operations. Here is an example:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class ReadFileExample {
public static void main(String[] args) {
String filePath = "path/to/file.txt";
try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
String line = reader.readLine();
while (line != null) {
System.out.println(line);
line = reader.readLine();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
The Scanner class has several methods, including reading from a file, for reading various sorts of data. The Scanner class permits you to remove determined information utilizing delimiters or read a file line by line. Here's an illustration:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReadFileExample {
public static void main(String[] args) {
String filePath = "path/to/file.txt";
try (Scanner scanner = new Scanner(new File(filePath))) {
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
System.out.println(line);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
In conclusion, the ability to read a file in Java is crucial for each Java developer. This blog article has looked at a number of ways to read a text file in Java using Eclipse, including the conventional FileReader class and more recent stream-based techniques made available by the Files class. We have also discussed the benefits of using the BufferedReader and Scanner classes for efficient file reading. You may efficiently handle data from files, interpret settings, and analyze logs in your Java applications by understanding these approaches.
Whether you read lines, read the complete file as a string, or handle binary data, remember to pick the approach that best satisfies your unique needs. You can confidently manage file reading jobs with these tools at your disposal, allowing you to maximize the functionality of your Java programs. Happy coding!
1. What is the difference between classpath and path in Java?
The primary difference between PATH and CLASSPATH is that Path is set for java tools in java programs like java and javac, which are utilized to assemble your code. Though CLASSPATH is utilized by System or Application class loaders to find and load compiled Java bytecodes put away in the .class document.
2. What data type does readline () return?
The readline method reads one line from the file and returns it as a string.
3. What in Java does readLine () do?
The readLine() method of Console class is used to read a single line of text from the console (specifically) while. The readLine() method of BufferedReader class is used to read a one line text from a given input source, for example, a file.
4. How to read records from files in Java?
You may use java. io's readLine() function. Line-by-line file reading to a String using a buffered reader. When the file is finished, this function returns null.
PAVAN VADAPALLI
Director of Engineering
Director of Engineering @ upGrad. Motivated to leverage technology to solve problems. Seasoned leader for startups and fast moving orgs. Working …Read More
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upGrad does not grant credit; credits are granted, accepted or transferred at the sole discretion of the relevant educational institution offering the diploma or degree. We advise you to enquire further regarding the suitability of this program for your academic, professional requirements and job prospects before enr...