java 保留2位小数

1.String.format保留2位小数

String.format("%.2f", "2.25558")

2.计算年比和环比

 
    private String getCompareRate(Float nowTotal, Float lastTotal) {
        if (nowTotal.equals(lastTotal)) {
            return "0.0%";
        }
        if(lastTotal==0.0){
               return "-";
        }
        return  String.format("%.2f", ((nowTotal - lastTotal) / lastTotal * 100)) + "%";
    }

    
    private String getCompareYoyRate(Float nowTotal, Float lastTotal) {
        if (nowTotal.equals(lastTotal)) {
            return "0.0%";
        }
        if(lastTotal==0.0){
            return "-";
        }
        return  String.format("%.2f", ((nowTotal - lastTotal) / nowTotal * 100)) + "%";
    }