How to print upto two decimal places in java using string builder?

Question

hi i am trying to print after dividing in string builder and printing that string builder let show me my code ,

string.append("Memomry usage:total:"+totalMemory/1024/1024+
"Mb-used:"+usageMemory/1024/1024+
" Mb("+Percentage+"%)-free:"+freeMemory/1024/1024+
" Mb("+Percentagefree+"%)");

in above code "totalmemory" and "freememory" is of double type having bytes value in point not null so i divide it by "1024" two times to get it in "Mb" and "string" is variable of string builder after using this code i am simply printing it a am getting result as shown below,

Used Memory:Memomry usage: 
total:13.3125Mb-used:0.22920989990234375Mb (0.017217645063086855%)
-free:13.083290100097656Mb (0.9827823549369131%)

i want to get percentage in twodecimal place and values of used and free memory in mb like this "used:2345.25" in this pattren remember

Hopes for your suggestions

Thanks in Advance

Answer 1

How about String.format()?

System.out.println(String.format("output: %.2f", 123.456));

Output:

output: 123.46

Answer 2

Try like this

    double d = 1.234567;
    DecimalFormat df = new DecimalFormat("#.##");
    System.out.print(df.format(d));

Using DecimalFormat, we can format the way we wanted to see.

Answer 3

You can use DecimalFormat to print out to two decimal places. So, to print x = 2345.2512 with two decimal places, you would write

NumberFormat f = new DecimalFormat("#.00");
System.out.println(f.format(x));

which will print 2345.25.

Answer 4

Even though it is possible to use NumberFormat and it's subclass DecimalFormat for this issue, these classes provide a lot of functionality that may not be required for your application.

If the objective is just pretty printing, I would recommend using the format function of the String class. For your specific code it would look like this:

string.append(String.format("Memomry usage:total:%1.2f Mb-used:%1.2f Mb(%1.2f %%)-free:%1.2f Mb(%1.2f %%)",totalMemory/1024/1024,usageMemory/1024/1024,Percentage,freeMemory/1024/1024,Percentagefree));

If you are intending to specify a standard format in which all numbers are represented irrespective of whether they are being parsed from strings or formatted to strings, then I would recommend using singletons of the *Format classes. They allow you to use standard formats and also to pass format descriptions between methods.

Hope that helps you select the right method to use in your application.