.net6API使用AutoMapper和DTO

        AutoMapper&＃xff0c;是一个转换工具&＃xff0c;说到AutoMapper时&＃xff0c;就不得不先说DTO&＃xff0c;它叫做数据传输对象(Data Transfer Object)。

        通俗的来说&＃xff0c;DTO就是前端界面需要用的数据结构和类型&＃xff0c;而我们经常使用的数据实体&＃xff0c;是数据库需要用的数据结构和类型&＃xff0c;它们2者负责的方向不一样&＃xff0c;经常需要进行转化&＃xff0c;那么此时AutoMapper就是一个转换工具&＃xff0c;它可以对数据实体和前端界面的数据进行转换&＃xff0c;反之&＃xff0c;也可以&＃xff0c;这样就加大了转换的效率&＃xff0c;如果不用AutoMapper时&＃xff0c;我们需要自己手写转换&＃xff0c;AutoMapper的目的就是提高转换效率&＃xff0c;不用写更多的判断代码了。

官网如下&＃xff1a;

Getting Started Guide — AutoMapper documentation

1.创建一个可以运行的.net6API程序

然后安装AutoMapper

2. 建立一个Model文件夹&＃xff0c;2个实体数据&＃xff0c;没有什么意义&＃xff0c;后面用于转换

A.cs

namespace AutoMapperDemo.Model
{
public class A
{
public int id { get; set; }
public string? name { get; set; }
public int age { get; set; }
public DateTime birthday { get; set; }
}
}


B.cs 

namespace AutoMapperDemo.Model
{
public class B
{
public int id { get; set; }
public string ? school { get; set; }
public int code { get; set; }
}
}


3. 建立一个Profile文件夹&＃xff0c;2个Dto实体数据&＃xff0c;字段可以不一样&＃xff0c;也可以一样&＃xff0c;和之前的Model进行转换

dto里面的字段&＃xff0c;就是前端需要显示的字段

ADto.cs

namespace AutoMapperDemo.Model
{
public class ADto
{
//wpf中可以集成INotifyPropertyChanged
public int id { get; set; }
public string? nameA { get; set; }
public int ageA { get; set; }
public DateTime birthdayA { get; set; }
}
}


BDto.cs

namespace AutoMapperDemo.Model
{
public class BDto
{
//wpf中可以集成INotifyPropertyChanged
public int id { get; set; }
public string ? schoolB { get; set; }
public int codeB { get; set; }
}
}


4. 建立AutoMapperProFile.cs

此文件最重要&＃xff0c;里面都是对实体类和DTO进行配置的&＃xff0c;相互转换的。

using AutoMapper;
using AutoMapperDemo.Model;
namespace AutoMapperDemo.Profile
{
public class AutoMapperProFile : MapperConfigurationExpression
{
//此文件的作用是&＃xff0c;手动增加配置文件&＃xff0c;项目中需要什么&＃xff0c;就加什么&＃xff0c;并且对字段进行映射匹配
public AutoMapperProFile()
{
//映射关系
//CreateMap();//如果A和ADto一样&＃xff0c;那么直接可以直接转换&＃xff0c;不需要指定字段了
CreateMap().
ForMember(a &＃61;> a.birthdayA, b &＃61;> b.MapFrom(b &＃61;> b.birthday))
.ForMember(a &＃61;> a.nameA, b &＃61;> b.MapFrom(b &＃61;> b.name))
.ReverseMap();//ForMember指定转换的字段值&＃xff0c;ReverseMap()意思是互相转换
//CreateMap().ForAllMembers(a &＃61;> a.Ignore());
// CreateMap().ReverseMap();
}
}
}


5.最后在Program.cs中注入

整体项目文件

using AutoMapper;
using AutoMapperDemo.Profile;
namespace AutoMapperDemo
{
public class Program
{
public static void Main(string[] args)
{
var builder &＃61; WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
//添加AutoMapper
var automapperConfig &＃61; new MapperConfiguration(config &＃61;>
{
config.SourceMemberNamingConvention &＃61; new LowerUnderscoreNamingConvention(); //Camel命名与Pascal命名的兼容,配置之后会映射property_name到PropertyName
config.DestinationMemberNamingConvention &＃61; new PascalCaseNamingConvention();
config.AddProfile(new AutoMapperProFile());
});
builder.Services.AddSingleton(automapperConfig.CreateMapper()); //只有一个单例
var app &＃61; builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();
}
}
}

6.使用&＃xff0c;如图所示

using AutoMapper;
using AutoMapperDemo;
using AutoMapperDemo.Model;
using Microsoft.AspNetCore.Mvc;
using System.Reflection;
namespace AutoMapperDemo.Controllers
{
[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
private static readonly string[] Summaries &＃61; new[]
{
"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
};
private readonly ILogger _logger;
private readonly IMapper mapper; //注入
public WeatherForecastController(ILogger logger, IMapper mapper)
{
_logger &＃61; logger;
this.mapper &＃61; mapper;
}
[HttpGet(Name &＃61; "GetWeatherForecast")]
public IEnumerable Get()
{
//将数据库的实体A&＃xff0c;转化成界面需要的ADto&＃xff0c;最终aDto是需要的值
A a &＃61; new A()
{
age &＃61; 1,
birthday &＃61; DateTime.Now,
id &＃61; 1,
name &＃61; "张三"
};
var aDto &＃61; mapper.Map(a);
//将界面的数据ADto&＃xff0c;转换成实体A&＃xff0c;最终a1是需要的值
ADto adto &＃61; new ADto()
{
ageA &＃61; 2,
birthdayA &＃61; DateTime.Now.AddDays(2),
id &＃61; 2,
nameA &＃61; "李四"
};
var a1 &＃61; mapper.Map(adto);
return Enumerable.Range(1, 5).Select(index &＃61;> new WeatherForecast
{
Date &＃61; DateTime.Now.AddDays(index),
TemperatureC &＃61; Random.Shared.Next(-20, 55),
Summary &＃61; Summaries[Random.Shared.Next(Summaries.Length)]
})
.ToArray();
}
}
}

总结&＃xff1a;AutoMapper还有一些复杂的转换&＃xff0c;这一切的转换规则&＃xff0c;都是根据业务来说的&＃xff0c;业务简单&＃xff0c;甚至不用AutoMapper也可以。主要就是在AutoMapperProFile文件中&＃xff0c;进行修改和增加&＃xff0c;以及使用的地方修改和增加。大部分都是2实体和DTO之间字段的匹配方式&＃xff0c;值的转换等等操作。