如何为在 Java 中扩展抽象类的类编写构建器模式？

Question

我有一个扩展抽象类“用户”的“客户端”类：

public abstract class User {
    private Long id;
    private String firstName;
    private String lastName;
    private String email;

   //getters and setters
}

public class Client extends User{
    private List<Account> accountList;

    //getters and setters
}

我已经为“客户端”类编写了构建器，但是我无法访问用户的字段（id、firstName、lastName、email）以在构建中使用它。怎么做？

public class Client extends User {
    private List<Account> accountList;

    public static Builder builder() {
        return new Client().new Builder();
    }


    public class Builder {
        private Builder() {
        }

        public Builder setAccountList(List<Account> accountList) {
            Client.this.accountList = accountList;
            return this;
        }

        public Client build() {
            return Client.this;
        }
    }
}

Answer 1

这是解决办法：

 public final class Client extends User {
        private List<Account> accountList;
    
        public List<Account> getAccountList() {
            return accountList;
        }
    
        public void setAccountList(List<Account> accountList) {
            this.accountList = accountList;
        }
    
        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            Client client = (Client) o;
            return Objects.equals(accountList, client.accountList);
        }
    
        @Override
        public int hashCode() {
            return Objects.hash(accountList);
        }
    
        public static Builder builder() {
            return new Client().new Builder();
        }
    
        public class Builder {
            private Builder() {
            }
    
            public Builder accountList(List<Account> accountList) {
                Client.this.accountList = accountList;
                return this;
            }
    
            public Builder id(Long id) {
                Client.this.setId(id);
                return this;
            }
    
            public Builder firstName(String firstName) {
                Client.this.setFirstName(firstName);
                return this;
            }
    
            public Builder lastName(String lastName) {
                Client.this.setLastName(lastName);
                return this;
            }
    
            public Builder email(String email) {
                Client.this.setEmail(email);
                return this;
            }
    
            public Builder password(String password) {
                Client.this.setPassword(password);
                return this;
            }
    
            public Builder role(User.Role role) {
                Client.this.setRole(role);
                return this;
            }
    
            public Builder dateOfBirth(LocalDate dateOfBirth) {
                Client.this.setDateOfBirth(dateOfBirth);
                return this;
            }
    
            public Client build() {
                return Client.this;
            }
        }
    }