java Archives - Page 7 of 12

Reading a file using FileInputStream

March 2, 2023February 2, 2023 by Manish Sahu

Reading a file using FileInputStream To read a file using FileInputStream in Java, follow these steps: Import the necessary packages:

import java.io.FileInputStream;
import java.io.IOException;

1 2	import java.io.FileInputStream; import java.io.IOException;

2. Create a FileInputStream object for the file you want to read:

FileInputStream fis = new FileInputStream("filename.txt");

1	FileInputStream fis = new FileInputStream("filename.txt");

3. Create a buffer array to store the data you read from the file:

byte[] buffer = new byte[1024];

1	byte[] buffer = new byte[1024];

4. Use the read method of … Read more

Concatenating two strings in Java

February 2, 2023February 2, 2023 by Manish Sahu

public class StringConcate {

    public static void main(String[] args) {
        String s1 = "Welcome to";
        String s2 = " Java";
        String s3 = s1 + s2;
        System.out.println(s3);
        String s4 = s1.concat(s2);
        System.out.println(s4);
    }
}

public class StringConcate {

public static void main(String[] args) {

String s1 = "Welcome to";

String s2 = " Java";

String s3 = s1 + s2;

System.out.println(s3);

String s4 = s1.concat(s2);

System.out.println(s4);

}

The + operator can be used for concatenation of strings. concat(String str) is a method of String class that concatenate two strings and return a String.

Basics of Applet in Java

February 4, 2023February 2, 2023 by manish

The Java Applet is a special Java program that are primarily used in a internet programming. Applet program runs on a web browser at client side. Applet program are used to make the web site more dynamic. Applet program embedded in a HTML page and hosted on a web server. Applet Skeleton/ Structure Applet skeleton … Read more

indexof and lastindexof Java Examples

February 1, 2023February 1, 2023 by Manish Sahu

public class StringIndexOf {

    public static void main(String[] args) {
        String sentence = "This is a ball. its color is black";
        System.out.println("first index of \"l\" is " + sentence.indexOf('l'));
        System.out.println("first index of \"l\" after position 15 is " + sentence.indexOf('l', 15));
        int i = sentence.lastIndexOf('l');
        System.out.println("last index of \"l\" is " + i);
        System.out.println("last index of \"l\" is " + sentence.lastIndexOf('l',23));
     }
}

public class StringIndexOf {

public static void main(String[] args) {

String sentence = "This is a ball. its color is black";

System.out.println("first index of \"l\" is " + sentence.indexOf('l'));

System.out.println("first index of \"l\" after position 15 is " + sentence.indexOf('l', 15));

int i = sentence.lastIndexOf('l');

System.out.println("last index of \"l\" is " + i);

System.out.println("last index of \"l\" is " + sentence.lastIndexOf('l',23));

}

indexOf(int ch) returns int value that is the first occurrence of specified character in given string. Counting start from 0. If character not found it returns -1 indexOf(int ch, int fromIndex) returns int value that is the first occurrence of specified character in given string after specified position. If character not found it returns … Read more

Reading title and description of URL using jsoup

February 1, 2023February 1, 2023 by manish

This is a sample program to read title and description of specified url. Wh have used java html parser jsoup for this program. for that you have to include jsoup-1.7.2.jar(used in this program). First we have to connect to url using Document doc Jsoup.connect(url).get(); To get title call title() that will return String value String … Read more

High quality thumbnail generation in java

February 1, 2023January 31, 2023 by manish

I am generating high quality thumbnail in java for that I am using java-image-scaling High quality image scaling library which is provided under Change license to The BSD 3-Clause License For running this program you have to include java-image-scaling-0.8.6.jar and Filter.jar This is example to generate thumbnail with maintaining aspect ratio

import com.mortennobel.imagescaling.AdvancedResizeOp;
import com.mortennobel.imagescaling.ResampleOp;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;

public class Test {

    public static void main(String[] args) throws IOException, Exception {
        Test tt = new Test();
        String sourceImagePath = "D:\\tt.jpg";
        String destinationPath = "D:\\tt1";
        String smallPath = "D:\\tt2";
        int pos = sourceImagePath.lastIndexOf(".");
        String imgFormat = sourceImagePath.substring(pos + 1);
        String thumbnailImage = destinationPath.concat(".").concat(imgFormat);
        String smallImg = smallPath.concat(".").concat(imgFormat);
        tt.getThumbnail(sourceImagePath, thumbnailImage, imgFormat, 500, 400);
        tt.getThumbnail(sourceImagePath, smallImg, imgFormat, 50, 50);
      }

    public void getThumbnail(String sourceImage, String thumbnailImage, String imgFormat, int picWidth, int picHeight)
            throws Exception {
        System.out.println(sourceImage + "  " + thumbnailImage + " " + picWidth + "  " + picHeight);

        Image image = javax.imageio.ImageIO.read(new File(sourceImage));
        double thumbRatio = (double) picWidth / (double) picHeight;
        int imageWidth = image.getWidth(null);
        int imageHeight = image.getHeight(null);
        double imageRatio = (double) imageWidth / (double) imageHeight;

        if (thumbRatio &lt; imageRatio) {
            picHeight = (int) (picWidth / imageRatio);
        } else {
            picWidth = (int) (picHeight * imageRatio);
        }

        if ((imageWidth &lt; picWidth) &amp;&amp; (imageHeight &lt; picHeight)) {
            picWidth = imageWidth;
            picHeight = imageHeight;
        } else if (imageWidth &lt; picWidth) {
            picWidth = imageWidth;
        } else if (imageHeight &lt; picHeight) {
            picHeight = imageHeight;
        }
        File f = new File(sourceImage);
        BufferedImage src = ImageIO.read(f);
        ResampleOp resampleOp = new ResampleOp(picWidth, picHeight);
        resampleOp.setUnsharpenMask(AdvancedResizeOp.UnsharpenMask.Soft);
        BufferedImage rescaled = resampleOp.filter(src, null);
        ImageIO.write(rescaled, imgFormat, new File(thumbnailImage));
   }

}

import com.mortennobel.imagescaling.AdvancedResizeOp;

import com.mortennobel.imagescaling.ResampleOp;

import java.awt.Color;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.RenderingHints;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import javax.imageio.ImageIO;

public class Test {

public static void main(String[] args) throws IOException, Exception {

Test tt = new Test();

String sourceImagePath = "D:\\tt.jpg";

String destinationPath = "D:\\tt1";

String smallPath = "D:\\tt2";

int pos = sourceImagePath.lastIndexOf(".");

String imgFormat = sourceImagePath.substring(pos + 1);

String thumbnailImage = destinationPath.concat(".").concat(imgFormat);

String smallImg = smallPath.concat(".").concat(imgFormat);

tt.getThumbnail(sourceImagePath, thumbnailImage, imgFormat, 500, 400);

tt.getThumbnail(sourceImagePath, smallImg, imgFormat, 50, 50);

}

public void getThumbnail(String sourceImage, String thumbnailImage, String imgFormat, int picWidth, int picHeight)

throws Exception {

System.out.println(sourceImage + " " + thumbnailImage + " " + picWidth + " " + picHeight);

Image image = javax.imageio.ImageIO.read(new File(sourceImage));

double thumbRatio = (double) picWidth / (double) picHeight;

int imageWidth = image.getWidth(null);

int imageHeight = image.getHeight(null);

double imageRatio = (double) imageWidth / (double) imageHeight;

if (thumbRatio < imageRatio) {

picHeight = (int) (picWidth / imageRatio);

} else {

picWidth = (int) (picHeight * imageRatio);

}

if ((imageWidth < picWidth) && (imageHeight < picHeight)) {

picWidth = imageWidth;

picHeight = imageHeight;

} else if (imageWidth < picWidth) {

picWidth = imageWidth;

} else if (imageHeight < picHeight) {

picHeight = imageHeight;

}

File f = new File(sourceImage);

BufferedImage src = ImageIO.read(f);

ResampleOp resampleOp = new ResampleOp(picWidth, picHeight);

resampleOp.setUnsharpenMask(AdvancedResizeOp.UnsharpenMask.Soft);

BufferedImage rescaled = resampleOp.filter(src, null);

ImageIO.write(rescaled, imgFormat, new File(thumbnailImage));

}

Java Program Structure and First Program

January 30, 2023January 30, 2023 by manish

Here we will see the structure of the java program and create a java first program in notepad and run it 1. Structure of Java Program Let’s see the basic structure of the java program

class className {

    //main method of java program
    public static void main(String args[]) {
        //program execution starts from main method
    }
}

class className {

//main method of java program

public static void main(String args[]) {

//program execution starts from main method

}

Here: class- is write to create a class. class_name – is the name of the class. It is an … Read more

double array java- java double array declare initialize access

January 30, 2023January 30, 2023 by manish

Double array java is a Java array with double values. All values are stored in contineous memory location Declaring double array in Java General syntax to declare array is dataType [] arrayName; dataType: Any primitive or user-defined data types like int, char, float, double. etc [] : notation to represent an array. arrayName: name of … Read more

Write a program to find greatest number in a 3*3 array

January 29, 2023January 28, 2023 by manish

Write a program to find the greatest number in a 3*3 array. The program is supposed to receive 9 integer numbers as command-line arguments. Program to Print 3*3 array in Java Reading 9 integer numbers as command-line arguments and assigning it to 3*3 matrix and printing it Program Steps are Create a Java class declare … Read more

Character Stream I/O in Java

January 27, 2023January 26, 2023 by manish

In a java programming, like a Byte stream Character stream is also used for input-output for 16 bit. But Byte streams are used to perform input and output of 8-bit. Most common Character streams classes are, FileReader and FileWriter. FileReader- FileReader uses for reads two bytes at a time. FileWriter– FileWriter uses for writes two bytes at a … Read more