求救：编译显示“无法从静态上下文中引用非静态 方法”是怎么回事

[gdufs_lswu]

import java.util.Scanner;
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());
}
}
class Tools
{
final static int START_TAX=2000;
double tax;
public double computeTax(double wage)
{
if(wage-START_TAX<=0){
tax=0;
return tax;
}
if(wage-START_TAX<=500)
{
tax=(wage-2000)*0.05;
return tax;
}
if((wage-START_TAX>500)&&(wage-START_TAX<=2000))
{
tax=(wage-2000)*0.1-25;
return tax;
}
if(wage-START_TAX>2000)
{
tax=(wage-2000)*0.15-125;
return tax;
}
}
}

[xiongyu2006]

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());
	}
}

[Ken_Wg]

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

[xiongyu2006]

如果必须要这样调用的话，得这样。供楼主参考

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());
	}
}

[echola_2020]

[Quote=引用 3 楼 xiongyu2006 的回复:]

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……
[/Quote]
+1
“无法从静态上下文中引用非静态 方法”：
public double computeTax(){
tax=Tools.computeTax(wage);
return tax;
}
这里用对类的静态方法调用，没有new Tools().computeTax(wage),
而public double computeTax(double wage)
声明的是实例方法，只能通过对象实例调用。
还有return那一句的变量作用域问题。

[gdufs_lswu]

谢谢各位大虾点评，懂了哈