从零开始学习ABP vNext开发 （六）创建应用层

现在我们来创建应用层，这样客户端只与应用层打交道就可以了。
与前面创建领域层模块和数据访问EF模块一样，我们在解决方案中增加.Net Core类库项目，作为服务层模块，将项目命名为ZL.AbpNext.Poem.Application，我们需要使用Nuget管理器，为项目增加必要的依赖项，如下：

图片.png

然后，增加一个Abp模块，名称为PoemApplicationModule，这个模块依赖于PoemCoreModule。
接下来，创建一个目录Poems，在这个目录中增加一个Dto类PoetDto:

namespace ZL.AbpNext.Poem.Application.Poems
{
    public class PoetDto:EntityDto<int>
    {
        public string Name { get; set; }

        public string Description { get; set; }
    }
}

DTO的目的是隔离客户端与领域模型，但很多情况下，DTO与领域模型基本上是相同的，ABP使用AutoMapper实现DTO到领域实体的映射。这需要创建一个映射Profile:

using ZL.AbpNext.Poem.Core.Poems;

namespace ZL.AbpNext.Poem.Application.Poems
{
    public class PoemAppAutoMapperProfile : Profile
    {
        public PoemAppAutoMapperProfile()
        {
            CreateMap<Poet, PoetDto>();
        }
    }
}

还需要在模块中进行声明：

using System;
using Volo.Abp.AutoMapper;
using Volo.Abp.Modularity;
using ZL.AbpNext.Poem.Application.Poems;
using ZL.AbpNext.Poem.Core;

namespace ZL.AbpNext.Poem.Application
{
    [DependsOn(
        typeof(PoemCoreModule), 
        typeof(AbpAutoMapperModule))]
    public class PoemApplicationModule : AbpModule
    {
        public override void ConfigureServices(ServiceConfigurationContext context)
        {
            Configure<AbpAutoMapperOptions>(options =>
            {
                options.AddProfile<PoemAppAutoMapperProfile>(validate: true);
            });
        }
    }
}

现在创建IPoemAppService接口：

using System;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;

namespace ZL.AbpNext.Poem.Application.Poems
{
    public interface IPoemAppService:IApplicationService
    {
        /// <summary>
        /// 获取诗人分页
        /// </summary>
        /// <param name="dto"></param>
        /// <returns></returns>
        PagedResultDto<PoetDto> GetPagedPoets(PagedResultRequestDto dto);
    }
}

我们先只增加一个函数，获取分页的诗人。然后我们创建PoemAppService：

using System.Collections.Generic;
using System.Linq;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;
using Volo.Abp.Domain.Repositories;
using Volo.Abp.Uow;
using ZL.AbpNext.Poem.Core.Poems;

namespace ZL.AbpNext.Poem.Application.Poems
{
    public class PoemAppService : ApplicationService, IPoemAppService
    {
        private readonly IRepository<Poet> _poetRepository;
        public PoemAppService(IRepository<Poet> poetRepository)
        {
            _poetRepository = poetRepository;
        }
        public PagedResultDto<PoetDto> GetPagedPoets(PagedResultRequestDto dto)
        {
           using (var uow = UnitOfWorkManager.Begin(new AbpUnitOfWorkOptions()))
            {
                var count = _poetRepository.Count();
                var lst = _poetRepository.OrderBy(o => o.Id).PageBy(dto).ToList();
                var items = new List<PoetDto>();
                
                return new PagedResultDto<PoetDto>
                {
                    TotalCount = count,
                    Items = ObjectMapper.Map<List<Poet>, List<PoetDto>>(lst)
                };
            }
            
        }
    }
}

到这里，应用层编写完成，下面使用Client调用应用层。
首先，在PoemConsoleClientModule中增加PoemApplicationModule依赖：

using Volo.Abp.Autofac;
using Volo.Abp.Modularity;
using ZL.AbpNext.Poem.Application;
using ZL.AbpNext.Poem.Core;
using ZL.AbpNext.Poem.EF;

namespace ZL.AbpNext.Poem.ConsoleClient
{
    [DependsOn(
    typeof(AbpAutofacModule),
    typeof(PoemCoreModule),
    typeof(PoemApplicationModule),
    typeof(PoemDataModule))]
    public class PoemConsoleClientModule:AbpModule
    {

    }
}

然后，改造Service，使用服务层访问数据：

using Microsoft.EntityFrameworkCore;
using System;
using System.Linq;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Domain.Repositories;
using Volo.Abp.Uow;
using ZL.AbpNext.Poem.Application.Poems;
using ZL.AbpNext.Poem.Core.Poems;

namespace ZL.AbpNext.Poem.ConsoleClient
{
    public class Service : ITransientDependency
    {
        //IRepository<Poet> repository;
        //IUnitOfWorkManager uowManager;
        IPoemAppService appService;
        //public Service(IRepository<Poet> repository, IUnitOfWorkManager uowManager)
        //{
        //    this.repository = repository;
        //    this.uowManager = uowManager;
        //}
        public Service(IPoemAppService appService)
        {
            this.appService = appService;
        }
        public void Run()
        {
            //Console.WriteLine("你好");
            //using (var uow = uowManager.Begin(new AbpUnitOfWorkOptions()))
            //{
            //    //获取第一个诗人
            //    //var poet = repository.FirstOrDefault();
            //    var poet = repository.AsQueryable().Include(p => p.Poems).FirstOrDefault();
            //    Console.WriteLine(poet.Name);
            //    Console.WriteLine(poet.Poems.Count());
            //    Console.WriteLine(poet.Poems.ToList()[0].Author.Name);
            //}
            var res=appService.GetPagedPoets(new Volo.Abp.Application.Dtos.PagedResultRequestDto { MaxResultCount = 10, SkipCount = 0 });
            Console.WriteLine(res.TotalCount);
            foreach(var dto in res.Items)
            {
                Console.WriteLine(dto.Name);
            }
        }
    }
}

运行如下：

图片.png

作者：寻找无名的特质
链接：https://www.jianshu.com/p/610c9b8b3ecf
来源：简书
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