如何在jasperReport中对字符串列求和

Question

I need to retrieve sum of a String column so i wrote this :

<variable name="totalQt" class="java.lang.Integer" calculation="Sum">
    <variableExpression>
      <![CDATA[Integer.parseInt($F{QTARTBP}.replaceAll(" ", ""))]]>

     </variableExpression>
</variable>

But i'm getting this error :

....
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:504)
at java.lang.Integer.parseInt(Integer.java:527)
at   
 articleBonPreparation_1385730226859_237481.evaluateEstimated(articleBonPreparation_1385730226859_237481:428)

 at net.sf.jasperreports.engine.fill.JREvaluator.evaluateEstimated(JREvaluator.java:254)

So there are empty string , so how to use zero in that case , i wrote thiw but it's wrong :

    <variableExpression>

      <![CDATA[$F{QTARTBP}.equals("") ? 0 : Integer.parseInt($F{QTARTBP}.replaceAll(" ", ""))]]>

    </variableExpression>

Any idea will be appreciated

Answer 1

It would be useful to see what input data you are using, but despite that, it's clear that your code will fail if the value of $F{QTARTBP} is a single space ( " " ). You could try the following expression instead, which will include the single space in your empty string check and will return 0 instead:

$F{QTARTBP}.replaceAll(" ", "").equals("") ? 0 : Integer.parseInt($F{QTARTBP}.replaceAll(" ", ""))

You should be aware that this is will still fail if any of your input strings cannot be interpreted as an integer.

Answer 2

Jasper are not to calculate - you should generate String in your java-code. And calculate what you need in java too.

Upd. This answer is incorrect. I learned JR more deeper and understand it.