：编译显示“无法从静态上下文中引用非静态 方法”是咋回事

import java.util.Scanner;class Tools{    final static int START_TAX = 2000;    double tax;    public double computeTax(double wage)    {        if (wage - START_TAX <= 0)        {            tax = 0;        }        if (wage - START_TAX <= 500)        {            tax = (wage - 2000) * 0.05;        }        if ((wage - START_TAX > 500) && (wage - START_TAX <= 2000))        {            tax = (wage - 2000) * 0.1 - 25;        }        if (wage - START_TAX > 2000)        {            tax = (wage - 2000) * 0.15 - 125;        }        return tax;// 把大括号里面的return语句去掉，直接在外面return。    }}public class Salary{    String employeeId = "";    double wage = 0;    static double tax = 0;    double realWage = 0;    public double computeTax()    {        tax = new Tools().computeTax(wage);// 这里没必要把此函数设置为static的。        return tax;    }    public double computeRealWage()    {        realWage = wage - this.computeTax();        return realWage;    }    public static void main(String[] args)    {        Salary salary = new Salary();        Scanner sc = new Scanner(System.in);        System.out.println("职工号");        salary.employeeId = sc.nextLine();        System.out.println("税前工资");        salary.wage = sc.nextDouble();        System.out.println("职工号" + salary.employeeId + "税前工资" + salary.wage                + "扣税" + salary.computeTax() + "实发    工资"                + salary.computeRealWage());    }}
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静态属性和方法只能被静态到代码块访问，在非静态到代码块中访问静态到方法当然不行了，你可以将被调用的方法设置成静态的
------解决方案--------------------
如果必须要这样调用的话，得这样。供楼主参考
Java code
import java.util.Scanner;class Tools{    final static int START_TAX = 2000;    private static double tax;//这里要设置为static     public static double computeTax(double wage) ////这里也要设置为static     {        if (wage - START_TAX <= 0)        {            tax = 0;        }        if (wage - START_TAX <= 500)        {            tax = (wage - 2000) * 0.05;        }        if ((wage - START_TAX > 500) && (wage - START_TAX <= 2000))        {            tax = (wage - 2000) * 0.1 - 25;        }        if (wage - START_TAX > 2000)        {            tax = (wage - 2000) * 0.15 - 125;        }        return tax;    }}public class Salary{    String employeeId = "";    double wage = 0;    static double tax = 0;    double realWage = 0;    public double computeTax()    {        tax =Tools.computeTax(wage);        return tax;    }    public double computeRealWage()    {        realWage = wage - this.computeTax();        return realWage;    }    public static void main(String[] args)    {        Salary salary = new Salary();        Scanner sc = new Scanner(System.in);        System.out.println("职工号");        salary.employeeId = sc.nextLine();        System.out.println("税前工资");        salary.wage = sc.nextDouble();        System.out.println("职工号" + salary.employeeId + "税前工资" + salary.wage                + "扣税" + salary.computeTax() + "实发工资"                + salary.computeRealWage());    }}
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探讨


如果必须要这样调用的话，得这样。供楼主参考
Java code

import java.util.Scanner;

class Tools
{
    final static int START_TAX = 2000;
    private static double tax;//这里要设置为static 

    public static double computeTax(d……