格式化浮点值
浮点数可以使用带有'f'
标志的 String.format
格式化为十进制数
//Two digits in fracttional part are rounded
String format1 = String.format("%.2f", 1.2399);
System.out.println(format1); // "1.24"
// three digits in fractional part are rounded
String format2 = String.format("%.3f", 1.2399);
System.out.println(format2); // "1.240"
//rounded to two digits, filled with zero
String format3 = String.format("%.2f", 1.2);
System.out.println(format3); // returns "1.20"
//rounder to two digits
String format4 = String.format("%.2f", 3.19999);
System.out.println(format4); // "3.20"
浮点数可以使用 DecimalFormat
格式化为十进制数
// rounded with one digit fractional part
String format = new DecimalFormat("0.#").format(4.3200);
System.out.println(format); // 4.3
// rounded with two digit fractional part
String format = new DecimalFormat("0.##").format(1.2323000);
System.out.println(format); //1.23
// formatting floating numbers to decimal number
double dv = 123456789;
System.out.println(dv); // 1.23456789E8
String format = new DecimalFormat("0").format(dv);
System.out.println(format); //123456789