java 計算同比增長工具類

java計算同比增長率的工具類

爲了數據的嚴謹性，統一裝換爲BigDecimal,話不多說，看代碼。

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package com.pig4cloud.pigx.admin.api.util;

import java.math.BigDecimal;


public class PercentCount {

	public String percentBigDecimal(BigDecimal preNum,BigDecimal sufNum){
		double result = countDecimal(preNum,sufNum);
		if(result>0){
			return "+"+result+"%";
		}
		if(result<0){
			return result+"%";
		}
		if(result==0){
			return "+"+0+"%";
		}
		return null;
	}
	public  double countDecimal(BigDecimal preNum,BigDecimal sufNum){
		boolean preBoolean = verifyNum(preNum);
		boolean sufBoolean = verifyNum(sufNum);
		//同時爲true計算
		if(preBoolean && sufBoolean){
			boolean b = verifyEqual(preNum, sufNum);
			if (b == false){
				return realCountDecimal(preNum,sufNum);
			}
			if (b){
				return 0;
			}
		}
		if(preBoolean == false && sufBoolean ==false){
			return 0;
		}
		if(sufBoolean ==false){
			return 100;
		}
		return  0;
	}
	//驗證數字是否爲零和null
	public boolean verifyNum(BigDecimal num){
		if(null !=num && num.compareTo(BigDecimal.ZERO)!=0 ){
			return true;
		}
		return false;
	}

	//驗證兩個數字是否相等
	public boolean verifyEqual(BigDecimal preNum,BigDecimal sufNum){
		int n = preNum.compareTo(sufNum);
		//比較 -1 小於   0 等於    1 大於
		if(n==0){
			return true;
		}
		return false;
	}
	//真正計算
	public double realCountDecimal(BigDecimal preNum,BigDecimal sufNum){
		//(前面的數字-後面的數字)/後面的數字*100
		BigDecimal bigDecimal = (preNum.subtract(sufNum)).divide(sufNum).multiply(new BigDecimal("100")).setScale(2, BigDecimal.ROUND_UP);
		if (bigDecimal.compareTo(BigDecimal.ZERO) !=0){
			return  bigDecimal.doubleValue();
		}
		return 0;
	}

	public static void main(String[] args) {
		PercentCount p = new PercentCount();
		BigDecimal a = new BigDecimal("3");
		BigDecimal b = new BigDecimal("1");
		String percent = p.percentBigDecimal(a, b);
		System.out.println(percent);
	}

}