.net core API DTO AutoMapper的使用

1. 安装依赖包
   
2. 创建model

namespace DTOMapper.Model
{
    public class Person
    {

        public int? ID { get; set; }

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public bool? Sex { get; set; } = true;

        public DateTime BirthDay { get; set; }

        public string? Address { get; set; }
    }
}

3. 创建config

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;

namespace DTOMapper.Model
{
    public class PersonConfig : IEntityTypeConfiguration<Person>
    {
        public void Configure(EntityTypeBuilder<Person> builder)
        {
            builder.ToTable("person");
            builder.HasKey(x => x.ID);
            builder.Property(x => x.ID).HasColumnName("id").ValueGeneratedOnAdd();
            builder.Property(x => x.BirthDay).HasColumnName("birthday");
            builder.Property(x => x.FirstName).HasColumnName("firstname");
            builder.Property(x => x.LastName).HasColumnName("lastname");
            builder.Property(x => x.Sex).HasColumnName("sex");
            builder.Property(x => x.Address).HasColumnName("address");
        }
    }
}

4. 创建dbhelper

using Microsoft.EntityFrameworkCore;

namespace DTOMapper.Model
{
    public class DBHelper:DbContext
    {
        public DbSet<Person> Persons { get; set; }
        public DBHelper(DbContextOptions<DBHelper> opetions):base(opetions)
        {

        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.ApplyConfigurationsFromAssembly(this.GetType().Assembly);
        }
    }
}

5. 创建DTO以及automapper

using AutoMapper;

namespace DTOMapper.Model
{
    public class PersonDTO
    {
        public int ID { get; set; }
        public string? Name { get; set; }

        public int Age { get; set; }

        public string Address { get; set; }
    }


	#这是class转成DTO，形如GET接口
    public class PersonToDTOMapper : Profile
    {
        public PersonToDTOMapper()
        {
            CreateMap<Person, PersonDTO>()
                .ForMember(dest => dest.Age, opt => opt.MapFrom(src => DateTime.Now.Year - src.BirthDay.Year))
            .ForMember(dest => dest.Name, opt => opt.MapFrom(src => $"{ src.FirstName}{src.LastName}"))
            .ForMember(dest => dest.ID, opt => opt.MapFrom(src => src.ID));
        }
    }


	#这个是在dto转成class时候使用，形如post接口
    public class PersonDTOTOPerson : Profile
    {
        public PersonDTOTOPerson()
        {
            CreateMap<PersonDTO, Person>().AfterMap((dto, person) => person.FirstName = dto.Name.Split(':')[0])
            .AfterMap((dto, person) => person.LastName = dto.Name.Split(':')[1])
            //.ForMember(x => x.LastName, opt => opt.MapFrom(src => GetName(src.Name, 1))); 这种以及上述的aftermap均可
           .ForMember(x => x.BirthDay, opt => opt.MapFrom(src => GetBirthday(src.Age)))
           .ForMember(x=>x.ID,opt=>opt.Ignore());//这个是忽略传入的ID，数据库自动生成即可
        }

        public string GetName(string value, int index)
        {
            return value.Split(':')[index];
        }
        public DateTime GetBirthday(int age)
        {
            DateTime dt = DateTime.UtcNow;
            return dt.AddYears(-age);
        }
    }
}

6. controller

using DTOMapper.Model;
using Microsoft.AspNetCore.Mvc;
using AutoMapper;
// For more information on enabling Web API for empty projects, visit https://go.microsoft.com/fwlink/?LinkID=397860

namespace DTOMapper.Controllers
{
    [Route("api/[controller]/[action]")]
    [ApiController]
    public class EllisController : ControllerBase
    {
        public readonly DBHelper _dBHelper;
        private readonly IMapper _mapper;

        public EllisController(DBHelper dBHelper, IMapper mapper)
        {
            _dBHelper = dBHelper;
            _mapper = mapper;
        }

        // GET: api/
        [HttpGet]
        public PersonDTO Get(int id)
        {
            var value = _dBHelper.Persons.Where(x=>x.ID == id).FirstOrDefault();

            PersonDTO result = _mapper.Map<PersonDTO>(value);

            return result;

        }

        
        [HttpPost]
        public bool Post([FromBody]PersonDTO value) 
        {
            var person = _mapper.Map<Person>(value);
            _dBHelper.Persons.Add(person);
            _dBHelper.SaveChanges();

            return true;
        }
    }
}

7. programe.cs

builder.Services.AddDbContext<DBHelper>(opt =>
{
    opt.UseNpgsql(@"Host=192.168.214.133;Port=32222;Database=postgresdb;Username=postgresadmin;Password=admin123");
});
//一次添加多个mapper
builder.Services.AddAutoMapper(typeof(PersonToDTOMapper),typeof(PersonDTOTOPerson));

建表语句

CREATE TABLE public.person (
	id bigserial NOT NULL,
	firstname varchar NULL,
	lastname varchar NULL,
	birthday timestamptz NULL,
	address varchar NULL,
	sex bool null,
	primary key(id)
);

https://stackoverflow.com/questions/4987872/ignore-mapping-one-property-with-automapper

https://dev.to/moe23/net-6-automapper-data-transfer-objects-dtos-49e

https://stackoverflow.com/questions/54858116/using-string-split-in-automapper-issue

源码