除法 小数位 bigDecimal_习惯累积沉淀_新浪博客

http://www.jb51.net/article/43513.htm 

public class Test_1 {
public static void main(String[] args) {
System.out.println(0.06+0.01);
System.out.println(1.0-0.42);
System.out.println(4.015*100);
System.out.println(303.1/1000);
}
}

 

运行结果如下
0.06999999999999999
 0.5800000000000001
 401.49999999999994
 0.30310000000000004

cost/2  改成

BigDecimal b1 = new BigDecimal(cost);

Double costDivide2 = b1.divide(new BigDecimal(2)).doubleValue();

就ok了   直接cost/2 得到0.061602000000000004