如何在Java中正确舍入值？

import java.text.DecimalFormat;
import java.math.RoundingMode;

public class Main {
    public static void main(String[] args) {
        double number = 3.14159;
        
        DecimalFormat df = new DecimalFormat("#.##");
        df.setRoundingMode(RoundingMode.HALF_UP);
        
        System.out.println(df.format(number)); // 输出3.14
    }
}

import java.math.BigDecimal;
import java.math.RoundingMode;

public class Main {
    public static void main(String[] args) {
        double number = 3.14159;
        
        BigDecimal bd = new BigDecimal(number);
        bd = bd.setScale(2, RoundingMode.HALF_UP);
        
        System.out.println(bd); // 输出3.14
    }
}