![Following example demonstrates how to use Fileinputstream
to read data from a file :
import java.io.*
public class ReadFileExample {
public static void main(String[] args) {
try {
FileInputStream fileinput = new
FileInputStream ("file.txt");
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = fileInput.read(buffer))!=-1){
System.out.println/new String buffer, 0, bytesread));
}
fileInput.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the example above, we create a
FilelnputStream object to read data
from a file called "file.txt".
We then create a byte array of size 1024
to read a chunk of data from the file.
We use the read() method to read data
into the buffer untill the end of the file is
reached, and then we close the
FilelnputStream object.
Finally, we print the data that we read
from the file to the console](https://image.slidesharecdn.com/oopswithjavaunit2-250705182004-3737f270/85/OOPs-with-Java_unit2-pdf-sarthak-bookkk-23-320.jpg)
![import java.io.*;
public class Write File Example {
public static void main(String[] args) {
try {
FileOutputStream fileOutput = new
FileOutputStream("file.txt");
String data ="This is some data that will be written to a file";
byte[] bytes = data.getBytes();
fileOutput.write(bytes);
fileOutput.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
In the example above, we create a FileOutputStream
object write data to a file called "file.txt".
We then create a string that contains some data that we
wants write to the file.
We convert this string to a byte array using the getbytes()
method and then we use the write() method to write the
data to the file.
Finally, we close the FileOutputStream object.](https://image.slidesharecdn.com/oopswithjavaunit2-250705182004-3737f270/85/OOPs-with-Java_unit2-pdf-sarthak-bookkk-25-320.jpg)
OOPs with Java_unit2.pdf. sarthak bookkk
- 1. Unit :- 2 Exception Handling Object Oriented Programming with Java An exception is something that is left out or not done on purpose. An exception to a rule does not follow that rule. In Java “an event that occurs during the execution of a program that disrupts the normal flow of instructions” is called an exception. This is generally an unexpected or unwanted event which can occur either at compile-time or run-time in application code.
- 2. In Short errors and exceptions represent different types of problems that can occur during program execution. Errors are usually caused by serious problems that cannot be recovered from, while exceptions are used to handle recoverable errors within a program.
- 4. Control Flow in Exceptions
- 5. The JVM starts the search from the method where the exception occurred and then goes up the call stack, checking each method in turn for a catch block that can handle the exception. If a catch block is found, the JVM transfers control to that block and the exception is considered to be handled. JVM Reaction to Exceptions
- 6. In Exception handling , we should have an alternate source through which we can handle the Exception.
- 18. Input / Output Basics
- 22. Reading and Writing File in Java Reading from a file: 1. In Java, the FilelnputSream class is used for reading binary data from a file. 2. It is an input stream that reads bytes from a file in a file system. 3.To read data from a file using FileInputStream, these steps you need to follow :- Step 1: Create an instance of the FileInputStream class and pass the path of the file that you want to read as an argument to its constructor. Step 2: Create a byte array of a fixed size to read a chunk of data from the file. Step 3: Use the read() method of the FileInputStream class to read data from the file into the byte array. This method returns the number of bytes read , or -1 if the end of the file has been reached. Step 4: Continue reading data from the file until the read() method returns -1. Step 5: Close the FileInputStream object using to release the close() method to release any system resources associated with it.
- 23. Following example demonstrates how to use Fileinputstream to read data from a file : import java.io.* public class ReadFileExample { public static void main(String[] args) { try { FileInputStream fileinput = new FileInputStream ("file.txt"); byte[] buffer = new byte[1024]; int bytesRead = 0; while ((bytesRead = fileInput.read(buffer))!=-1){ System.out.println/new String buffer, 0, bytesread)); } fileInput.close(); } catch (IOException e) { e.printStackTrace(); } } } In the example above, we create a FilelnputStream object to read data from a file called "file.txt". We then create a byte array of size 1024 to read a chunk of data from the file. We use the read() method to read data into the buffer untill the end of the file is reached, and then we close the FilelnputStream object. Finally, we print the data that we read from the file to the console
- 24. Writing in a file: 1. In Java, FileOutputStream class in used for writing binary data to a file. 2. It is an output stream that writes bytes to a file in a file system. 3. To write data to a file using FileOutputStream, you need to follow these steps: Step 1: Create an instance of the FileOutputStream class and pass the path of the file that you want to write as an argument to its constructor. If the file dosen't exist, it will be created automatically. Step 2: Create a byte array that contains the date that you want to write to the file. Step 3: Use the write() method of the FileOutputStream class to write the data to the File This method writes the entire array to the the file. Step 4: Close the FileOutputStream object using the close() method to release any system resources associated with it. Following example demonstrates how to use FileOutputstream to write data to a file :
- 25. import java.io.*; public class Write File Example { public static void main(String[] args) { try { FileOutputStream fileOutput = new FileOutputStream("file.txt"); String data ="This is some data that will be written to a file"; byte[] bytes = data.getBytes(); fileOutput.write(bytes); fileOutput.close(); } catch (IOException e) { e.printStackTrace(); } } } In the example above, we create a FileOutputStream object write data to a file called "file.txt". We then create a string that contains some data that we wants write to the file. We convert this string to a byte array using the getbytes() method and then we use the write() method to write the data to the file. Finally, we close the FileOutputStream object.
- 26. Multithreading