Java 遵循生成器模式的确切代码，但出现错误

在阅读了一篇流行的博客文章后，我尝试构建自己的构建器模式，但出现了一个错误，所以我认为我做错了什么。我反复检查了我的代码，但还是不断地出错。所以我决定从博客上复制整个代码，但我仍然得到一个错误，我不知道为什么

blogpost中的代码：

---

您没有在

BankAccount

类上定义字段，只在

Builder

上定义字段。在他们实现构建器的文章中有一条评论说“为简洁起见省略字段”。您需要遵循第一个示例，其中：

公共类银行账户{
私人长帐号；
私人字符串所有者；
私人字符串分支；
私人双平衡；
私人双重利益；
公共银行账户（长账号、字符串所有者、字符串分支、双余额、双利率）{
this.accountNumber=accountNumber；
this.owner=所有者；
this.branch=分支；
这个平衡=平衡；
this.interestRate=interestRate；
}
//为简洁起见，省略了getter和setter。
}

然后您需要创建getter和setter，并从

生成器

调用setter，例如：

公共类银行账户{
//...
公共无效setAccountNumber（长值）{
this.accountNumber=值；
}
//在建筑商中
account.setAccountNumber（此.accountNumber）；
}

“为简洁起见省略字段”，但错误在于这些字段显然不存在！如果您在代码中省略了它们，那么我们应该怎么做？不要发布代码或错误的图像。您可能需要查看以创建一个。

public class BankAccount {
    public static class Builder {
        private long accountNumber; //This is important, so we'll pass it to the constructor.
        private String owner;
        private String branch;
        private double balance;
        private double interestRate;
        public Builder(long accountNumber) {
            this.accountNumber = accountNumber;
        }
        public Builder withOwner(String owner){
            this.owner = owner;
            return this;  //By returning the builder each time, we can create a fluent interface.
        }
        public Builder atBranch(String branch){
            this.branch = branch;
            return this;
        }
        public Builder openingBalance(double balance){
            this.balance = balance;
            return this;
        }
        public Builder atRate(double interestRate){
            this.interestRate = interestRate;
            return this;
        }
        public BankAccount build(){
            //Here we create the actual bank account object, which is always in a fully initialised state when it's returned.
            BankAccount account = new BankAccount();  //Since the builder is in the BankAccount class, we can invoke its private constructor.
            account.accountNumber = this.accountNumber;
            account.owner = this.owner;
            account.branch = this.branch;
            account.balance = this.balance;
            account.interestRate = this.interestRate;
            return account;
        }
    }
    //Fields omitted for brevity.
    private BankAccount() {
        //Constructor is now private.
    }
    //Getters and setters omitted for brevity.
}