使用Asp.net核心创建Web API。我创建的端点将返回所有客户的列表(目前我只为1个客户播放了数据库)。 当我从Postman执行GET请求时,我得到了一个"无法获得任何响应"。 当我通过Chrome导航到该端点时,我看到响应,但返回的json似乎缺少括号。
[
{
"customerId":1,
"firstName":"John",
"lastName":"Doe",
"email":"johndoe@email.com",
"address": {
"addressId":1,
"addressLine1":"2119 Some street",
"addressLine2":null,
"locality":"New York",
"region":"New York",
"country":"USA",
"postCode":"10005",
"customerId":1
我想知道格式错误的Json响应是否是Postman无法正常工作的原因。我想了解什么是错的。在我的简单例子中,我有什么问题可能会让我头疼。
我的存储库:
public class LodgingRepository : ILodgingRepository
{
private readonly LodgingCrmContext _context;
public LodgingRepository( LodgingCrmContext context )
{
_context = context;
}
public async Task<IEnumerable<Customer>> GetCustomersAsync( )
{
return await _context.Customers
.Include( c => c.Address )
.ToListAsync( );
}
}
我的控制器
[Route( "api/customers" )]
public class CustomerController : Controller
{
private readonly ILodgingRepository _lodgingRepository;
public CustomerController( ILodgingRepository lodgingRepository )
{
_lodgingRepository = lodgingRepository;
}
[HttpGet]
public async Task<IActionResult> GetCustomersAsync( )
{
return Ok( await _lodgingRepository.GetCustomersAsync( ) );
}
}
启动
public void ConfigureServices( IServiceCollection services )
{
services.AddMvc( ).AddMvcOptions( options =>
options.OutputFormatters.Add( new XmlDataContractSerializerOutputFormatter( ) ) );
services.AddDbContext<LodgingCrmContext>( options =>
options.UseSqlServer( Configuration.GetConnectionString( "DefaultConnection" ) ) );
services.AddScoped<ILodgingRepository, LodgingRepository>( );
}
public void Configure( IApplicationBuilder app, IHostingEnvironment env, LodgingCrmContext lodgingCrmContext )
{
if( env.IsDevelopment( ) )
{
app.UseDeveloperExceptionPage( );
}
app.UseMvc( );
app.Run( async ( context ) => { await context.Response.WriteAsync( "Hello World!" ); } );
}
地址实体
public class Address
{
[Key]
[DatabaseGenerated( DatabaseGeneratedOption.Identity )]
public int AddressId { get; set; }
[Required]
[MaxLength( 254 )]
public string AddressLine1 { get; set; }
[MaxLength( 254 )]
public string AddressLine2 { get; set; }
[Required]
[MaxLength( 60 )]
public string Locality { get; set; }
[Required]
[MaxLength( 50 )]
public string Region { get; set; }
[Required]
[MaxLength( 60 )]
public string Country { get; set; }
[Required]
[MaxLength( 9 )]
public string PostCode { get; set; }
[ForeignKey( nameof(CustomerId) )]
public int CustomerId { get; set; }
public Customer Customer { get; set; }
}
答案 0 :(得分:1)
问题是,每次响应尝试序列化地址时,它都会反弹关联的客户,然后循环重复。这会导致堆栈溢出。
如果您查看JSON,您会看到它停止,就像它必须再次为客户做的那样
创建DTO并在从服务返回时将实体映射到它们,以避免通过EF导航属性进行循环引用。
[HttpGet]
public async Task<IActionResult> GetCustomersAsync() {
var records = await _lodgingRepository.GetCustomersAsync();
var model = await ConvertToDTO(records); //<-- perform convertions here
return Ok(model);
}