long型別 轉換成小數， 利用bigdicimal
阿新 • • 發佈：2019-01-30
long 類裡的方法，將一個long型別轉換成float public float floatValue() { return (float)value; } Long paid = 0L; if(searchResult[14] != null){ paid = Long.valueOf(searchResult[14].toString()); } BigDecimal bd2 = new BigDecimal(paid.floatValue()); Float f = bd2.divide(divide, 2, BigDecimal.ROUND_HALF_UP).floatValue(); bean.setParkingFee(f); BigDecimal.ROUND_HALF_UP 往上取：別如 1.23------>1.3
下面是百度的例子
BigDecimal bigLoanAmount = new BigDecimal("具體數值"); //建立BigDecimal物件
BigDecimal bigInterestRate = new BigDecimal("具體數值");
BigDecimal bigInterest = bigLoanAmount.multiply(bigInterestRate); //BigDecimal運算
NumberFormat currency = NumberFormat.getCurrencyInstance(); //建立貨幣格式化引用
NumberFormat percent = NumberFormat.getPercentInstance(); //建立百分比格式化用
percent.setMaximumFractionDigits(3); //百分比小數點最多3位
//利用BigDecimal物件作為引數在format()中呼叫貨幣和百分比格式化
System.out.println("Loan amount:\t" + currency.format(bigLoanAmount));
System.out.println("Interest rate:\t" + percent.format(bigInterestRate));
System.out.println("Interest:\t" + currency.format(bigInterest));| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
Loan amount: ￥129,876,534,219,876,523.12
Interest rate: 8.765%
Interest: ￥11,384,239,549,149,661.69
常見用法：
初始化 BigDecimal a= new BigDecimal("1.35");
對數值取值：
1.a.getScale(1,BigDecimal.ROUND_DOWN);
取一位小數，直接刪除後面多餘位數，故取值1.3.
2.a.getScale(1,BigDecimal.ROUND_UP);
取一位小數，刪除後面位數，進一位，故取值1.4.
3.a.getScale(1,BigDecimal.ROUND_HALF_UP);
取一位小數，四捨五入，故取值1.4.
4.a.getScale(1,BigDecimal.ROUND_HALF_DOWN);
取一位小數，四捨五入，但是5也是捨棄，故取值1.3.
|