Read Raspberry Pi system temperature in Java

This exercise show how to read Pi's system temperature in Java, using ProcessBuilder with command of "vcgencmd measure_temp".

Read Raspberry Pi system temperature in Java

import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.Scanner;

/**
 * @web helloraspberrypi.blogspot.com
 */
public class readTemp {

    public static void main(String[] args) {

        // Example to run "dir" in Windows
        String[] command = {"vcgencmd", "measure_temp"};
        StringBuilder cmdReturn = new StringBuilder();
        try {
            ProcessBuilder processBuilder = new ProcessBuilder(command);
            Process process = processBuilder.start();
            
            try (InputStream inputStream = process.getInputStream()) {
                int c;
                while ((c = inputStream.read()) != -1) {
                    cmdReturn.append((char) c);
                }
            }
            
            System.out.println(cmdReturn.toString());
            String stringTemp = measure_temp_toString(cmdReturn.toString());
            System.out.println("Get the numerical part as String: " + stringTemp);
            System.out.println("converte to float: " + cnvStringToFloat(stringTemp));

        } catch (IOException ex) {
            System.out.println(ex.toString());
        }
        
    }
    
    private static String measure_temp_toString(String src){
        return src.replaceAll("[^0123456789.]", "");
    }
    
    private static float cnvStringToFloat(String src){

        float result = (float)0.0;
        Scanner scanner = new Scanner(src);
        while(scanner.hasNext()){
            if(scanner.hasNextFloat()){
                result = scanner.nextFloat();
            }else{
                scanner.next(); //ignore
            }
        }
        return result;
    }
    
}