java四舍五入保留两位小数方法整理

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.NumberFormat;

public class test {
public static void main(String[] args) {
String str="86.64466666";
BigDecimal bd = new BigDecimal(Double.parseDouble(str));
System.out.println(bd.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue());
System.out.println("=================");
DecimalFormat df = new DecimalFormat("#.00");
System.out.println(df.format(Double.parseDouble(str)));
System.out.println("=================");
System.out.println(String.format("%.2f", Double.parseDouble(str)));
System.out.println("=================");
NumberFormat nf = NumberFormat.getNumberInstance();
nf.setMaximumFractionDigits(2);
System.out.println(nf.format(Double.parseDouble(str)));
}
}