J2ME - How to convert double to string without the power to 10 representation (E-05)

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故里飘歌
故里飘歌 2021-01-18 08:15

I have a double value . I want to store it in String with out E notation (in J2ME)

Example

Double value 6.887578324E9 Want to show as 6887578342

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4条回答
  • 2021-01-18 08:54

    You can use Java Formatter, just specify how many decimals do you want with the string.

    E.g. a double converted to a number with one decimal:

    Formatter format = new Formatter();
    String mystring = format.formatNumber(DOUBLENUMBERVARIABLE,1);
    System.out.println(mystring );
    
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  • 2021-01-18 08:56

    Have a look at this article: Converting Double to String without E notation

    You can make use of the [NumberFormat][2] or [DecimalFormat][3] class to acheive what you are looking for.

    Here is the code:

    NumberFormat f = NumberFormat.getInstance();
    f.setGroupingUsed(false);
    String refinedNumber = f.format(doubleVariable);
    
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  • 2021-01-18 09:02

    Normally you can use piece of code below, but not for j2me.

    BigDecimal.valueOf(doubleVariable)
    
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  • 2021-01-18 09:10

    You can create your own method to do that, or use some already existing library. Javolution, for example, gives you the class and method TypeFormat.format(double d, int digits, boolean scientific, boolean showZero, Appendable a) Check Javolution, it has lots of nice utilities, but if the only thing you need is to format numbers, just write your own method. Here is a quick hack for big numbers

        private static String nosci(double d) {
        if(d < 0){
            return "-" + nosci(-d);
        }
        String javaString = String.valueOf(d);
        int indexOfE =javaString.indexOf("E"); 
        if(indexOfE == -1){
            return javaString;
        }
        StringBuffer sb = new StringBuffer();
        if(d > 1){//big number
            int exp = Integer.parseInt(javaString.substring(indexOfE + 1));
            String sciDecimal = javaString.substring(2, indexOfE);
            int sciDecimalLength = sciDecimal.length();
            if(exp == sciDecimalLength){
                sb.append(javaString.charAt(0));
                sb.append(sciDecimal);              
            }else if(exp > sciDecimalLength){
                sb.append(javaString.charAt(0));
                sb.append(sciDecimal);
                for(int i = 0; i < exp - sciDecimalLength; i++){
                    sb.append('0');
                }
            }else if(exp < sciDecimalLength){
                sb.append(javaString.charAt(0));
                sb.append(sciDecimal.substring(0, exp));
                sb.append('.');
                for(int i = exp; i < sciDecimalLength ; i++){
                    sb.append(sciDecimal.charAt(i));
                }
            }
          return sb.toString();
        }else{
            //for little numbers use the default or you will
            //loose accuracy
            return javaString;
        }       
    
    
    }
    
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