How do you round to n decimal places a calculated field using hibernate annotation @Format?

@Column(name = "weight")
@Formula("round(weight/1000)")
private Double weight;

CodePudding user response：

Just use Java Decimalformat util class. You should use that pattern: ###.##

If you want to round n decimal places then do:

String s = ".";
for(int i = 0; i<n; i  ) {
s  = "#";
}
if(n <= 0) {
s = "";
}
System.out.println(new DecimalFormat("###"   s).format(ur number));

idk if it's right. If a made any misteak then correct me.

CodePudding user response：

You could multiply the number with 10 to the power n, round it off to the nearest whole number and then divide it with 10 to the power n again.

@Column(name = "weight")
@Formula("round(weight/1000)")
private Double weight;
n=5;                            //just for demonstration purposes
weight *= Math.pow(10,n);       //multiplying it by 10 to the power n
math.round(weight);             //rounding it off
weight /= Math.pow(10,n);       //getting the rounded off value for weight