Java 数字格式

Question

我正在尝试在程序中使用 java 的 NumberFormat 类和 getPercentInstance 方法来计算税金.我希望程序显示的是带两位小数的百分比。现在，当我之前尝试将小数格式化为百分比时，Java 将 0.0625 显示为 6%。如何使 Java 显示这样的小数或将 0.0625 表示为“6.25%”？

代码片段:

NumberFormat fmt1 = NumberFormat.getCurrencyInstance();
NumberFormat fmt2 = NumberFormat.getPercentInstance();

System.out.print("Enter the quantity of items to be purchased: ");
quantity = scan.nextInt();

System.out.print("Enter the unit price: ");
unitPrice = scan.nextDouble();

subtotal = quantity * unitPrice;
final double TAX_RATE = .0625;
tax = subtotal * TAX_RATE;
totalCost = subtotal + tax;

System.out.println("Subtotal: " + fmt1.format(subtotal));
System.out.println("Tax: " + fmt1.format(tax) + " at " + fmt2.format(TAX_RATE));
System.out.println("Total: " + fmt1.format(totalCost));

Answer 1

您可以在 NumberFormat 上设置最小小数位数使用 setMinimumFractionDigits(int) 的实例.

例如:

NumberFormat f = NumberFormat.getPercentInstance();
f.setMinimumFractionDigits(3);
System.out.println(f.format(0.045317d));

产生:

4.532%