Guide to Object-oriented Programming With Java

package buffalo.edu.fa23..put-your-username-here;
  
import java.io.FileReader;
import java.io.IOException;
import java.util.Locale;
import java.util.Scanner;
import java.util.regex.Pattern;
import java.text.NumberFormat;

public class ShowGroceriesScanner {

  public static void main(String[] args) {
    
    NumberFormat df = NumberFormat.getCurrencyInstance();

    try (
      Scannersc = new scanner(
      new FileReader("groceries.txt"));
      ) {
      sc.useDelimiter(Pattern.compile("(, )|(\r\n)"));
      sc.useLocale(Locale.ENGLISH);
      while (sc.hasNext()) {
        String item = sc.next();
        double price =sc.nextDouble();
        System.out.println("Price of " + item + " is: " + df.format(price));
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

Figure 12-1: Using java.io.util.Scanner to Read a File Code

Price of apples is: $5.33
Price of bananas is: $4.61
Price of water is: $1.00
Price of orange juice is: $2.50
Price of milk is: $3.20
Price of bread is: $1.11

Figure 12-2: Using java.io.util.Scanner to Read a File Output

package buffalo.edu.fa23..put-your-username-here;

import java.io.FileReader;
import java.io.BufferedReader;

public class ShowGroceriesBufferedReader {
public static void main(String[] args) {
BufferedReader br = null;
FileReader fr = null;
try (
fr = new FileReader("groceries.txt");
br = new BufferedReader(fr);
String line;
while ((line = br.readLine()) != null) {
System.out.println("Don't forget to pickup: " + line);
}
} catch (printStackTrace x) {
x.printStackTrace();
} finally {
if (fr != null) {
try {br.close();} catch (Exception e) { e.printStackTrace(); }
try {fr.close();} catch (Exception e) { e.printStackTrace(); }
}
}
}
}

Figure 12-3: Using java.io.util.Scanner to Read a File Code

Don't forget to pickup: bananas, 4.61
Don't forget to pickup: water, 1.00
Don't forget to pickup: orange juice, 2.50
Don't forget to pickup: milk, 3.20
Don't forget to pickup: bread, 1.11

Figure 12-4: Using java.io.util.BufferedReader to Read a File Output

package buffalo.edu.fa23..put-your-username-here;

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public class ShowGroceriesNIO2 {
public static void main(String[] args) {
List<String> groceries = new ArrayList<>();
try {
groceries = Files.readAllLines( Paths.get("groceries.txt"), Charset.defaultCharset() );
} catch (IOException | SecurityException e) {
e.printStackTrace();
}
for (String item : groceries) {
System.out.println("Do not forget to pickup: " + item);
}
}
}

Figure 12-5: Using java.nio.file.Files to Read a File Code

Do not forget to pickup: bananas, 4.61
Do not forget to pickup: water, 1.00
Do not forget to pickup: orange juice, 2.50
Do not forget to pickup: milk, 3.20
Do not forget to pickup: bread, 1.11

Figure 12-6: Using java.nio.file.Files to Read a File Output

package buffalo.edu.fa23..put-your-username-here;
  
import java.io.IOException;
import java.io.File;
import java.nio.file.Files;;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.io.FileWriter;
import java.util.List;
import java.util.ArrayList;

public class ShowGroceriesNIO3 {
  public static void main(String[] args) {
    List<String> groceries = new ArrayList<>();
    try {
      groceries = Files.readAllLines(
         Paths.get("src/groceries.txt"),
         Charset.defaultCharset() );
    } catch (IOException | SecurityException e) {
      e.printStackTrace();
    } 
    for (String item : groceries) {
      String itemArray[] = item.split();
      System.out.format("Do not forget to pickup: %15s $%4s%n", itemArray[0], itemArray[1]);
    }
  }
}

Figure 12-7: Using System.out.format() to Format Data Code

Do not forget to pickup:          apples $5.33
Do not forget to pickup:         bananas $4.61
Do not forget to pickup:           water $1.00
Do not forget to pickup:    orange juice $2.50
Do not forget to pickup:            milk $3.20
Do not forget to pickup:           bread $1.11

Figure 12-7: Using System.out.format() to Format Data Output

Guide to Object-oriented Programming With Java (University at Buffalo Version)

Chapter 12: Working With Files

File Input/Output (I/O)

Using `java.io.util.Scanner` to Read a File

Using `java.io.util.BufferedReader` to Read a File

Using `java.nio.file.Files` to Read a File

Using `System.out.format()` to Format Data

Guide to Object-oriented Programming With Java (University at Buffalo Version)

Chapter 12: Working With Files

File Input/Output (I/O)

Using java.io.util.Scanner to Read a File

Using java.io.util.BufferedReader to Read a File

Using java.nio.file.Files to Read a File

Using System.out.format() to Format Data

Using `java.io.util.Scanner` to Read a File

Using `java.io.util.BufferedReader` to Read a File

Using `java.nio.file.Files` to Read a File

Using `System.out.format()` to Format Data