java 四舍五入的问题--五舍六入
package test;import java.math.BigDecimal;import java.math.MathContext;import java.math.RoundingMode;import java.text.DecimalFormat;public class testFormat {public static void main(String[] args) {//第1种Double dd = 0.125;try {DecimalFormat df = new DecimalFormat("#.##");System.out.println(df.format(dd));} catch (RuntimeException e) {e.printStackTrace();}//第2种MathContext v = new MathContext(2, RoundingMode.HALF_DOWN);BigDecimal a = new BigDecimal("0.875", v);System.out.println(a);//第3种float a1 = 123.2354f;float b = (float) (Math.round(a1 * 100)) / 100;System.out.println(b);//第4种float ft = 134.3445f;int scale = 2;// 设置位数int roundingMode = 4;// 表示四舍五入，可以选择其他舍值方式，例如去尾，等等.BigDecimal bd = new BigDecimal((double) ft);bd = bd.setScale(scale, roundingMode);ft = bd.floatValue();System.out.println(ft);//第5种MathContext v2 = new MathContext(2, RoundingMode.HALF_UP);BigDecimal a2 = new BigDecimal("0.875", v2);System.out.println(a2);}}