在Java中将String转换为double。 更改印刷双打的格式

Question

I am reading a following CSV file in java and

1191196800.681 - !AIVDM,1,1,,,13aG?N0rh20E6sjN1J=9d4<00000,0*1D

Here is my code to read this CSV file and convert the 1st column of the CSV file (which is a String) to a double

public class ReadCSV {

public static void main(String[] args) {

    try {
        BufferedReader CSVFile = new BufferedReader(new FileReader(
                "C:\\example.txt"));

        try {
            String dataRow = CSVFile.readLine();

            while (dataRow != null) {
                String[] dataarray = dataRow.split("-");

                String temp = dataarray[0];

                double i = Double.parseDouble(temp);

                System.out.println(temp);
                System.out.println(i);
                dataRow = CSVFile.readLine();

            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

}

}

When I execute the code I get the following values

1191196800.681 
1.191196800681E9

Why is the value of variable "temp" and "i" not the same. What changes must I do in the code to get the following values:

1191196800.681 
1191196800.681 

Thanks in advance.

Answer 1

temp and i are exactly the same, just the double value is formatted in scientific notation. You can format it differently if you like using DecimalFormat for instance.

Answer 2

Yups vizier is correct what you need to do is this:

public static void main(String[] args) throws Exception {
    // TODO Auto-generated method stub
    String dataRow = "1191196800.681";


        String[] dataarray = dataRow.split("-");

        String temp = dataarray[0];
        DecimalFormat df = new DecimalFormat("#.###");
        double i = Double.parseDouble(temp);

        System.out.println(temp);
        System.out.println(df.format(i));

}

Answer 3

The other result is in scientific notation, but is the same.

If you want change the representation you can use String.format("%.3f", i) , which represents the number with 3 decimals