2020个人所得税，税前工资 和 到手工资的相互计算源码（java）

1、个人所得纳税规则表

薪资	纳税率
0-5k	0
5k-8k	3%
8k-17k	10%
17-30k	20%
30k-40k	25%
40k-60k	30%
60k-85k	35%
85k+	45%

2、java 税前工资 和 到手工资的相互计算

package com.cxysl;

import java.util.Scanner;

public class Main {

    static double[][] rates = { { 0, 0,5000 }, { 5000, 0.03,7910 },
            { 8000, 0.1,16010}, { 17000, 0.2 ,26410},
            { 30000, 0.25,33910}, { 40000, 0.3 ,47910},
            { 60000, 0.35 ,64160}, { 85000, 0.45,64160} };


    public static void main(String[] args) {
        Main main = new Main();
        main.menu();
    }

    public void menu(){
        double x;       //税前工资
        double sum;     //到手工资
        System.out.println("--------------------------------------------------------------------------");
        System.out.println("1、税前工资算到手工资");
        System.out.println("2、到手工资算税前工资");
        Scanner reader = new Scanner(System.in);
        int i = reader.nextInt();

        if (i==1){
            System.out.print("输入你的税前工资:\t");
            x = reader.nextDouble();
            sum = getSum(x);
            System.out.println("你的到手工资为:\t"+sum);
            menu();
        }

        else if (i==2){
            System.out.print("输入你的到手工资:\t");
            sum = reader.nextDouble();
            x =  getX(sum);
            System.out.println("你的税前工资为:\t"+x);
            menu();
        }

        else {
            System.out.print("输入错误");
            menu();
        }
    }


    //根据税前工资算到手工资
    public static double getSum(double x) {
        double b = 0;
        for (int i = 1; i < rates.length; i++) {
            if (x <= rates[i][0]) {
                break;
            } else if (x > rates[i][0]) {
                if (i==rates.length-1){
                    b = b + (x-rates[i][0])*rates[i][1];
                    System.out.print("1b"+i+":\t"+b);
                }
                else {
                    if(x > rates[i+1][0]) b = b + (rates[i+1][0]-rates[i][0])*rates[i][1];
                    else    b = b + (x-rates[i][0])*rates[i][1];
                    System.out.print("2b"+i+":\t"+b);
                }
                System.out.println("");
            }
        }
        System.out.println("x:"+x+"\t\tb:"+b+"\t\tsum:"+(x-b));
        return x-b;
    }

    //根据到手工资算税前工资
    public static double getX(double sum){
        double b = 0;
        double x = 0;
        for (int i = 1; i < rates.length; i++){
            if (sum > rates[i-1][2]) {      //本区间 需要交税
                if (sum <= rates[i][2] || i == rates.length-1){       //下区间不用交税 
//                    sum = x - (x-rates[i][0])*rates[i][1] - b;
                    x = (sum + b - rates[i][1] *rates[i][0]) / (1-rates[i][1]);
                    break;

                }else if(sum > rates[i][2]){       // 下区间也要交税
                    b = b + (rates[i+1][0]-rates[i][0])*rates[i][1];
                    System.out.println("b"+i+":\t"+b);
                }
            } else if(sum <= rates[i-1][2]){
                break;
            }
        }
        return x;
    }

}

3、运行效果展示

昨天15号刚发工资，但工资明细条还没发，就想知道自己这税前是几多工资，整了这程序。（不考虑社保、五险这些，这些我现在也还没有）
如果程序还有漏洞请留言 ~