当前位置：首页 > java >正文

ABP-Book Store Application中文讲解 - Part 6: Authors: Domain Layer

java 2025/7/6 3:28:43

1. 汇总

ABP-Book Store Application中文讲解-汇总-CSDN博客

2. 前一章

ABP-Book Store Application中文讲解 - Part 5: Authorization-CSDN博客

项目之间的引用关系。

BookAppService利用的是CurdAppService，里面帮我们实现了增删改查的所有方法，从本篇开始主要用于介绍手动撸代码的方式实现类似CurdAppService的方法，讲解DDD的最佳实践，权限控制利用Authorize设置。

并且介绍了哪些情况下需要用到Domain Sevice （例如判断唯一约束，一些entity的validation等），哪些情况不用Domain Serice。

1. 在Domain中创建Author.cs

2. 创建Domain service （AuthorManager）

2.1 为什么需要创建Domain Service

2.2 创建IAuthorRepository

2.3 创建Error Codes

2.4 创建Business Exception - AuthorAlreadyExistsException

2.5 创建AuthorManager

3. Domain Layer目录结构

4. 继续学习

1. 在Domain中创建Author.cs

在Acme.BookStore.Domain.Shared中创建AuthorConsts.cs

namespace Acme.BookStore;public static class AuthorConsts
{public const int MaxNameLength = 64;
}

在Acme.BookStore.Domain中创建Authors目录，然后创建Author.cs,继承FullAuditedAggregateRoot.

using System;
using Volo.Abp;
using Volo.Abp.Domain.Entities.Auditing;namespace Acme.BookStore.Authors;
public class Author : FullAuditedAggregateRoot<Guid>
{public string Name { get; private set; }public DateTime BirthDate { get; set; }/// <summary>/// 笔名？/// </summary>public string ShortBio { get; set; }private Author(){/* This constructor is for deserialization / ORM purpose */}internal Author(Guid id,string name,DateTime birthDate,string? shortBio = null): base(id){SetName(name);BirthDate = birthDate;ShortBio = shortBio;}internal Author ChangeName(string name){SetName(name);return this;}private void SetName(string name){Name = Check.NotNullOrWhiteSpace(name,nameof(name),maxLength: AuthorConsts.MaxNameLength);}
}

2. 创建Domain service （AuthorManager）

`2.1 为什么需要创建Domain Service`

Author 构造函数和 ChangeName 是 internal, 他们只能被用在同一个domain layer.因此需要在 Acme.BookStore.Domain项目中的Authors文件夹中创建 AuthorManager.cs

DDD tip: 不要引入域服务方法，除非它们确实需要并执行一些核心业务规则。对于这种情况，我们需要该服务能够强制惟一名称约束。

在创建在AuthorManager.cs之前需要一些前置条件：

2.2 创建IAuthorRepository

在Acme.BookStore.Domain的Authors目录创建IAuthorRepository.cs 接口

IAuthorRepository 扩展标准的 IRepository<Author, Guid> 接口, 因此 repository 中的所有方法在IAuthorRepository中都可用.
FindByNameAsync 用于 AuthorManager 根据名字查询Author
GetListAsync UI使用，获取用户列表、排序和过滤作者列表.

Standard Repository Methods

Generic Repositories provide some standard CRUD features out of the box:

GetAsync: Returns a single entity by its Id or a predicate (lambda expression).
Throws EntityNotFoundException if the requested entity was not found.
Throws InvalidOperationException if there are multiple entities with the given predicate.

FindAsync: Returns a single entity by its Id or a predicate (lambda expression).
Returns null if the requested entity was not found.
Throws InvalidOperationException if there are multiple entities with the given predicate.

InsertAsync: Inserts a new entity into the database.
UpdateAsync: Updates an existing entity in the database.
DeleteAsync: Deletes the given entity from the database.
This method has an overload that takes a predicate (lambda expression) to delete multiple entities to satisfy the given condition.

GetListAsync: Returns the list of all entities in the database.
GetPagedListAsync: Returns a limited list of entities. Gets skipCount, maxResultCount, and sorting parameters.
GetCountAsync: Gets the count of all entities in the database.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Volo.Abp.Domain.Repositories;namespace Acme.BookStore.Authors;public interface IAuthorRepository : IRepository<Author, Guid>
{Task<Author> FindByNameAsync(string name);Task<List<Author>> GetListAsync(int skipCount,int maxResultCount,string sorting,string filter = null);
}

2.3 创建Error Codes

Acme.BookStore.Domain.Shared中的BookStoreDomainErrorCodes.cs添加如下代码：

public const string AuthorAlreadyExists = "BookStore:00001";

2.4 创建Business Exception - AuthorAlreadyExistsException

创建AuthorAlreadyExistsException用于判断名字是否唯一。

需要在Acme.BookStore.Domain.Shared中的BookStoreDomainErrorCodes.cs中添加错误代码AuthorAlreadyExists

 public const string AuthorAlreadyExists = "BookStore:00001";

using Volo.Abp;namespace Acme.BookStore.Authors;public class AuthorAlreadyExistsException : BusinessException
{public AuthorAlreadyExistsException(string name): base(BookStoreDomainErrorCodes.AuthorAlreadyExists){WithData("name", name);}
}

2.5 创建AuthorManager

在Acme.BookStore.Domain中创建Authors目录创建AuthorManager.cs，继承DomainService.

using System;
using System.Threading.Tasks;
using Volo.Abp;
using Volo.Abp.Domain.Services;namespace Acme.BookStore.Authors;public class AuthorManager : DomainService
{private readonly IAuthorRepository _authorRepository;public AuthorManager(IAuthorRepository authorRepository){_authorRepository = authorRepository;}public async Task<Author> CreateAsync(string name,DateTime birthDate,string? shortBio = null){Check.NotNullOrWhiteSpace(name, nameof(name));var existingAuthor = await _authorRepository.FindByNameAsync(name);if (existingAuthor != null){throw new AuthorAlreadyExistsException(name);}return new Author(GuidGenerator.Create(),name,birthDate,shortBio);}public async Task ChangeNameAsync(Author author,string newName){Check.NotNull(author, nameof(author));Check.NotNullOrWhiteSpace(newName, nameof(newName));var existingAuthor = await _authorRepository.FindByNameAsync(newName);if (existingAuthor != null && existingAuthor.Id != author.Id){throw new AuthorAlreadyExistsException(newName);}author.ChangeName(newName);}
}