java - "non static method cannot be referenced from a static context"错误

Question

这个问题在这里已经有了答案:





Cannot make a static reference to the non-static method

(8 个回答)


7年前关闭。




这是我的第一篇文章，所以格式方面的人要轻松。另外，我对 Java 也很陌生。我的程序编译器出现错误，我不知道如何修复它。我知道我必须为我的静态函数创建一个实例，但我该怎么做呢？

 import java.awt.*;
    import javax.swing.*;
    import java.util.*;
    import java.io.*;

    public class TestAccount{
    public static void main (String[] args) {
    Account account = new Account(1122, 20000);
    Account.setAnnualInterestRate(4.5);

    account.withdraw(2500);
    account.deposit(3000);
    System.out.println("Balance is " + account.getBalance());
    System.out.println("Monthly interest is " +
      account.getMonthlyInterest());
    System.out.println("This account was created at " +
      account.getDateCreated());
  }
}

class Account {




    private int id=0;
    private double balance = 0;
    private static double annualInterestRate = 0;
    private Date dateCreated;


    public Account()
    {

        this.id =0;
        this.balance =0;
        this.annualInterestRate =0;
        this. dateCreated = new Date();

    }

    public Account(int id, double balance)
    {

    this.id =id;
    this.balance =balance;
    this. dateCreated = new Date();
    }


    public void setID(int id) {
    this.id=id;
    }

    public int getID() {
    return this.id;
    }


    public void setBalance(double balance) {
    this.balance = balance;
    }


    public double getBalance(){
    return this.balance;
    }


    ***public static void setAnnualInterestRate(double annualInterestRate){
    this.annualInterestRate = annualInterestRate;
    }***


    public double getAnnualInterestrate() {
    return this.annualInterestRate;
    }

    public Date getDateCreated() {
    return this.dateCreated;
    }

    public double getMonthlyInterest() {
    return (this.annualInterestRate)/12;
    }

    public void withdraw(double amount) {

        this.balance -=amount;
    }


    public void deposit(double amount)
    {
    this.balance += amount;
    }
}

Answer 1

这里有一个问题:

   public static void setAnnualInterestRate(double annualInterestRate){
    this.annualInterestRate = annualInterestRate;
    }

关键字 this引用一个对象，但该方法是静态的，因此该方法无权访问单个对象。删除 this关键词。我还建议查看 static keyword. 的含义。