IUB student will get practice code material here
Some important url that can help student
Variable in java
Java all data type with initialization
boolean b;
char c;
short s;
int i;
float f;
double d;
b=true;
i=10;
c='a';
b=true;
f=10.2f;
d=10.256;
System.out.println("i = "+i);
System.out.println("c = "+c);
System.out.println("b = "+b);
System.out.println("f = "+f);
System.out.println("d = "+d+f );
System.out.println("==============");
System.out.printf("i = %d\n",i);
System.out.printf("c = %c\n",c);
System.out.printf("b = %b\n",b);
System.out.printf("f = %.1f\n",f);
System.out.printf("d = %.2f\n",d );User Input
package beginnerjava;
import java.util.Scanner;
public class inputDemo {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
char ch;
ch=input.next().charAt(0);
if(ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u')System.out.print("Vowel\n");
else System.out.print("Consonant\n");
// By using switch statement
/*
switch(ch)
{
case 'a':
System.out.println("Vowel\n");
break;
case 'e':
System.out.println("Vowel\n");
break;
case 'i':
System.out.println("Vowel\n");
break;
case 'o':
System.out.println("Vowel\n");
break;
case 'u':
System.out.println("Vowel\n");
break;
default:
System.out.println("Consonant");
}
*/
}
}
Scanner input=new Scanner(System.in);
//=======Integer input====/
int number;
System.out.print("Enter any number: ");
number=input.nextInt();
System.out.println("Number = "+number);
input.nextLine();
//=======String input====/
String name;
System.out.print("Enter your name: ");
name =input.nextLine();
System.out.println("Welcome: "+name);
//=======double input====/
double num1;
num1=input.nextDouble();
System.out.println("Here is the double value: "+num1);Basic ArrayList Code
ArrayList Initialization & iteration
import java.util.ArrayList;
public class arraydemo {
public static void main(String[] args) {
ArrayList<String>list=new ArrayList();
list.add("Hello");
list.add("Hati");
/*
for(auto a:list) //by using for each loop
System.out.print(a + " ");
*/
for (int i = 0; i < list.size(); i++)
System.out.print(list.get(i) + " ");
}
}Scene switching code
Parent scene2Parent = FXMLLoader.load(getClass().getResource("Scene1.fxml"));//here switching scene fxml should be attached
Scene scene2 = new Scene(scene2Parent);
Stage stg2 = (Stage)((Node)event.getSource()).getScene().getWindow();
stg2.setScene(scene2);
stg2.show();Stage switching code
Parent fileChooserViewParent = FXMLLoader.load(getClass().getResource("window1.fxml"));//here switching stage fxml should be attached
Scene fileChooserViewScene = new Scene(fileChooserViewParent);
Stage newWindow = new Stage();
newWindow.setTitle("File Chooser Test Stage");
newWindow.setScene(fileChooserViewScene);
newWindow.show();File Reading & Writing
@FXML
private void createFileBtnOnClick(ActionEvent event) {
if(!isTextFileChkBox.isSelected() && !isBinFileChkBox.isSelected())
{
Alert a = new Alert(AlertType.ERROR);
a.setContentText("Oops! No fileType Selected. \nCan't save to file.");
a.showAndWait();
}
//=====creating text file code starts from here====/
if(isTextFileChkBox.isSelected()){
FileWriter fw=null;
try {
//write code to dump studArr in Stud.txt
//use FileWriter
File f = new File("studText.txt");
//FileWriter fw = new FileWriter(f);
if(f.exists())
fw = new FileWriter(f,true);
else
fw = new FileWriter(f);
//fw = new FileWriter("studText.txt");
String str="";
for(Student s: studArr){
str += s.getId()+","+s.getName()+","+s.getCgpa()+"\n";
//str += s;
//if toString is overridden to return
//return id+","+name+","+cgpa+"\n"
}
fw.write(str); //fw.write(s.toString());
fw.close();
} catch (IOException ex) {
//SHOW ex.toString() IN AN ALERT
}
/*
finally{
try {
fw.close();
} catch (IOException ex) {
Logger.getLogger(FXMLMainSceneController.class.getName()).log(Level.SEVERE, null, ex);
}
}
*/
}
//=====creating bin file code starts from here====/
if(isBinFileChkBox.isSelected()){
//write code to dump studArr in Stud.bin
//1: write the individual fields using data stream
try{
FileOutputStream fos = new FileOutputStream("studData.bin", true);
DataOutputStream dos = new DataOutputStream(fos);
for(Student s: studArr){
dos.writeInt(s.getId());
dos.writeUTF(s.getName());
dos.writeFloat(s.getCgpa());
}
dos.close();
}
catch(Exception e){
//SHOW e.toString() IN AN ALERT
}
//=======creating Object file code starts from here=======/
//2: write the Student instance using object stream
try{
FileOutputStream fos = new FileOutputStream("studObjects.bin",true);
ObjectOutputStream oos = new ObjectOutputStream(fos);
for(Student s: studArr)
oos.writeObject(s);
oos.close();
}
catch(Exception e){
//SHOW e.toString() IN AN ALERT
}
}
studArr.clear();
}
//=====Reading from text file code starts from here====/
@FXML
private void readFromTextFileBtnOnClick(ActionEvent event) {
//use BufferedReader OR Scanner
File file = new File("StudText.txt");
Scanner sc; String str=null;
try {
sc = new Scanner(file);
outputTxtArea.setText(null);
while(sc.hasNextLine()){
str=sc.nextLine();
String[] tokens;
tokens = str.split(",");
str = "Id="+tokens[0]+", Name="+tokens[1]
+", Cgpa="+tokens[2];
outputTxtArea.appendText(str+"\n");
//outputTxtArea.appendText("\n");
}
} catch (FileNotFoundException ex) {
Logger.getLogger(FXMLMainSceneController.class.getName()).log(Level.SEVERE, null, ex);
}
}
//=====Reading from Object-bin file code starts from here====/
@FXML
private void readFromBinFileUsingObjectStreamBtnOnClick(ActionEvent event) {
//use ObjectInputStream
ObjectInputStream ois=null;
try {
Student s;
//FileInputStream fis = new FileInputStream("studObjects.bin");
//ois = new ObjectInputStream(fis);
ois = new ObjectInputStream(new FileInputStream("StudObjects.bin"));
outputTxtArea.setText(null);
//int[] arr={1,2,3};
//System.out.println(arr[3]);
while(true){
s = (Student) ois.readObject();
//studArr.add((Student) ois.readObject());
outputTxtArea.appendText(s.toString()+"\n");
//outputTxtArea.appendText(s+"\n");
}
//ois.close();
}
catch(RuntimeException e){
e.printStackTrace();
//
}
catch (Exception ex) {
try {
if(ois!=null)
ois.close();
} catch (IOException ex1) { }
}
}
//=====Reading from bin file code starts from here====/
@FXML
private void readFromBinFileUsingDataStreamBtnOnClick(ActionEvent event) throws IOException {
FileInputStream fis = null;
DataInputStream dis = null;
try{
//FileInputStream fis = new FileInputStream("studData.bin");
File f = new File("studData.bin");
fis = new FileInputStream(f);
dis = new DataInputStream(fis);
//outputTxtArea.setText(null); //OK
//outputTxtArea.setText(""); // OK
outputTxtArea.clear();
while(true){
outputTxtArea.appendText(
"Id is: " + dis.readInt() +
", Name is: " + dis.readUTF() +
", Cgpa is: " + dis.readFloat() + "\n"
);
}
//dis.close();
}
catch(Exception e){
//Alert a = new Alert(AlertType.INFORMATION);
//a.setContentText(e.toString());
//a.setContentText("Content from Data file is loaded successfully.");
//a.showAndWait();
dis.close();
//SHOW e.toString() IN AN ALERT
}
}