BigDecimal這個類來實現加減乘除呢
package com.mmall.util;
import java.math.BigDecimal;
/ **
*敲程式碼的wqq
* /
public class BigDecimalUtil {
private BigDecimalUtil（）{
}
public static BigDecimal add（double v1，double v2）{
BigDecimal b1 = new BigDecimal（Double.toString（v1））;
BigDecimal b2 = new BigDecimal（Double.toString（v2））;
return b1.add（b2）;
}
public static BigDecimal sub（double v1，double v2）{
BigDecimal b1 = new BigDecimal（Double.toString（v1））;
BigDecimal b2 = new BigDecimal（Double.toString（v2））;
return b1.subtract（b2）;
}
public static BigDecimal mul（double v1，double v2）{
BigDecimal b1 = new BigDecimal（Double.toString（v1））;
BigDecimal b2 = new BigDecimal（Double.toString（v2））;
return b1.multiply（b2）;
}
public static BigDecimal div（double v1，double v2）{
BigDecimal b1 = new BigDecimal（Double.toString（v1））;
BigDecimal b2 = new BigDecimal（Double.toString（v2））;
return b1.divide（b2,2，BigDecimal.ROUND_HALF_UP）; //四捨五入，保留2位小數
//除不盡的情況
}
}