asked on

how to format a number as ###,### in JSP/Java

How to format a number as ###,###

I have the following code

<%
DecimalFormat df = new DecimalFormat("###,###");
long MySourceBytes = df.format((MyList.get(i).getSourceBytes())/1024);
%>

Now I have the following error

An error occurred at line: 367 in the jsp file: /view2.jsp
Generated servlet error:
C:\Documents and Settings\ezchen\.netbeans\5.5\apache-tomcat-5.5.17_base\work\Catalina\localhost\NFD\org\apache\jsp\view2_jsp.java:644: incompatible types
found : java.lang.String
required: long
long MySourceBytes = df.format((MyList.get(i).getSourceBytes())/1024);
^

How to fix this problem?

mrcoffee365

df.format returns a string. Why do you format it if you are going to convert it to a long?

If you want to turn the string into a long, then something like
Long.parseLong( aString )
works.

You'll have to take the comma outfor parseLong -- you might want to use the DecimalFormat parse method to convert the string back to a number.

bpmurray

Try this:
<%
DecimalFormat df = new DecimalFormat("###,###");
String MySourceBytes = df.format((MyList.get(i).getSourceBytes())/1024);
%>
...
I have <%=MySouceBytes%> Bytes!!

wasabi3689

ASKER

MySourceBytes must be long from get function, now I need to convert MySourceBytes long into string value, then df it

wasabi3689

ASKER

or
can I directly format a long value output as "###,###"?

ASKER CERTIFIED SOLUTION

bpmurray

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mrcoffee365

>>can I directly format a long value output as "###,###"?

No -- long is a long, which is a binary type. It doesn't have a string display format. That's why there are classes like DecimalFormat, for formatting binary number types like long, when you want to display the value of a long variable in a String format.