Java:如何设置 Double 的最大长度？

Question

如何设置 double 的最大长度？

double divSum = number1 / number2;  
String divDisplay = number1 + " / " + number2 + " = " + divSum + " "; 

JLabel divSumLabel= new JLabel();
divSumLabel.setText(divDisplay)

如何设置 divSum 的最大长度？

1/3 = 0.333333... 如何设置最大长度，使其仅为 0.333？

我可以做:
int maxLenght = 3;

String stringDivSum = String.valueOf(divSum);
String shortDivSum = null; 
if(stringDivSum.length() > maxLenght){
    shortDivSum = stringDivSum.substring(0, maxLenght);
}

String divDisplay = number1 + "/"+ number2 + "= "+ ShortDivSum + "";
但是当我执行 1/3 时，它会打印出 1/3 = 0.3？

Answer 1

Use String.format(...)

String.format()

double divSum = Double.parseDouble(String.format("%.3f",(double)number1  /  number2)) ;

double 。

We can specify the precision of a double or float. We use the "f" to indicate a floating-point. Before this we specify ".3" to mean "three numbers after the decimal."