math.round的四舍六入五成双

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我是靠谱客的博主乐观可乐，最近开发中收集的这篇文章主要介绍math.round的四舍六入五成双，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

数轴：-5 -4 -3 -2 -1 0 1 2 3 4 5

就是括号内的数+0.5之后，向下取值

System.out.println("1.9:__"+Math.round(1.4));//   输出1.9:__1
  System.out.println("1.8:__"+Math.round(1.3));//   输出1.8:__1
  System.out.println("1.7:__"+Math.round(1.2));//   输出1.7:__1
  System.out.println("1.6:__"+Math.round(1.1));//   输出1.6:__1
  System.out.println("1.5:__"+Math.round(1.0));//   输出1.5:__1
  System.out.println("1.4:__"+Math.round(0.9));//   输出1.4:__1
  System.out.println("1.3:__"+Math.round(0.8));//   输出1.3:__1
  System.out.println("1.2:__"+Math.round(0.7));//   输出1.2:__1
  System.out.println("1.1:__"+Math.round(0.6));//   输出1.1:__1
  System.out.println("1.0:__"+Math.round(0.5));//   输出1.0:__1
  System.out.println("0.9:__"+Math.round(0.4));//   输出0.9:__0
  System.out.println("0.8:__"+Math.round(0.3));//   输出0.8:__0
  System.out.println("0.7:__"+Math.round(0.2));//   输出0.7:__0
  System.out.println("0.6:__"+Math.round(0.1));//   输出0.6:__0
  System.out.println("0.5:__"+Math.round(0.0));//   输出0.5:__0
  System.out.println("0.4:__"+Math.round(-0.1));//   输出0.4:__0
  System.out.println("0.3:__"+Math.round(-0.2));//   输出0.3:__0
  System.out.println("0.2:__"+Math.round(-0.3));//   输出0.2:__0
  System.out.println("0.1:__"+Math.round(-0.4));//   输出0.1:__0
  System.out.println("0.0:__"+Math.round(-0.5));//   输出0.0:__0
  System.out.println("-0.1:__"+Math.round(-0.6));//   输出-0.1:__-1
  System.out.println("-0.2:__"+Math.round(-0.7));//   输出-0.2:__-1
  System.out.println("-0.3:__"+Math.round(-0.8));//   输出-0.3:__-1
  System.out.println("-0.4:__"+Math.round(-0.9));//   输出-0.4:__-1
  System.out.println("-0.5:__"+Math.round(-1.0));//   输出-0.5:__-1
  System.out.println("-0.6:__"+Math.round(-1.1));//   输出-0.6:__-1
  System.out.println("-0.7:__"+Math.round(-1.2));//   输出-0.7:__-1
  System.out.println("-0.8:__"+Math.round(-1.3));//   输出-0.8:__-1
  System.out.println("-0.9:__"+Math.round(-1.4));//   输出-0.9:__-1
  System.out.println("-1.0:__"+Math.round(-1.5));//   输出-1.0:__-1
  System.out.println("-1.1:__"+Math.round(-1.6));//   输出-1.1:__-2
  System.out.println("-1.2:__"+Math.round(-1.7));//   输出-1.2:__-2
  System.out.println("-1.3:__"+Math.round(-1.8));//   输出-1.3:__-2
  System.out.println("-1.4:__"+Math.round(-1.9));//   输出-1.4:__-2
  System.out.println("-1.5:__"+Math.round(-2.0));//   输出-1.5:__-2
  System.out.println("-1.6:__"+Math.round(-2.1));//   输出-1.6:__-2
  System.out.println("-1.7:__"+Math.round(-2.2));//   输出-1.7:__-2
  System.out.println("-1.8:__"+Math.round(-2.3));//   输出-1.8:__-2
  System.out.println("-1.9:__"+Math.round(-2.4));//   输出-1.9:__-2