double保留两位小数（四舍五入）

//val为处理double 数字，precsion为保留小数位数。

public static Double roundDouble(double val, int precision) {  
  Double ret = null;  
        try {  
           double factor = Math.pow(10, precision);  
           ret = Math.floor(val * factor + 0.5) / factor;  
        } catch (Exception e) {  
           e.printStackTrace();  
        }  
       return ret;  
    }

 

 

	//	格式化数据
	//将小数转化为百分数，保留2位小数，四舍五入，例：35.21%
	public static String formatRates(double val ) {   
		Double ret = null; 
		val = val*100 ;
		int precision = 2 ;
        try {   
           double factor = Math.pow(10, precision);   
           ret = new Double(Math.floor(val * factor + 0.5) / factor);   
        } catch (Exception e) {   
           e.printStackTrace();   
        }
        String tmp = String.valueOf(ret);
        if (tmp.substring(tmp.indexOf('.')+1).length()<2){
        	tmp = tmp + "0" ;
        }
       return tmp + "%";   
    } 

 

 写道

public static String getRoundValue(double value,int digit) {
digit = (digit < 0 ? 0 : digit );
String s = String.valueOf(new BigDecimal(value).setScale(digit, BigDecimal.ROUND_HALF_UP)
.doubleValue());
return (digit == 0 ? (s.substring(0,s.indexOf('.'))) : s);
}