JAVA中大精度的運算

public class BigDecimalTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		BigDecimal a = new BigDecimal(2);
		BigDecimal b = new BigDecimal(1000000000);
		//加
		BigDecimal add = a.add(b);
		System.out.println(add);
		//減
		BigDecimal sub = a.subtract(b);
		System.out.println(sub);
		//乘
		BigDecimal multiply = a.multiply(b);
		System.out.println(multiply);
		//除
		BigDecimal divide = a.divide(b);
		System.out.println(divide);
	}

}
Result:
1000000002
-999999998
2000000000
2E-9