.Net Core 配置之long类型 前端精度丢失和时间格式设置

在很多项目中，都采用的前后端分离的方式进行开发，经常遇到后台的long精度的数据到前端丢失不准确，显示效果为long类型（19位）的后几位为000，此时需要对long的字段进行设置，改变默认的返回类型，由long类型改变为string类型。所以需要全局自定义修改long类型的返回类型

1. using Newtonsoft.Json;
   
2. using Newtonsoft.Json.Serialization;
   
3. using System;
4.  
5. namespace NetCore3WebApiTemplate.Utility
   
6. {
   
7. public class CustomContractResolver : CamelCasePropertyNamesContractResolver
   
8. {
   
9. ///// <summary>
   
10. ///// 实现首字母小写
    
11. ///// </summary>
    
12. ///// <param name="propertyName"></param>
    
13. ///// <returns></returns>
    
14. //protected override string ResolvePropertyName(string propertyName)
    
15. //{
    
16. // return propertyName.Substring(0, 1).ToLower() + propertyName.Substring(1);
    
17. //}
18.  
19. /// <summary>
    
20. /// 对长整型做处理
    
21. /// </summary>
    
22. /// <param name="objectType"></param>
    
23. /// <returns></returns>
    
24. protected override JsonConverter ResolveContractConverter(Type objectType)
    
25. {
    
26. if (objectType == typeof(long))
    
27. {
    
28. return new JsonConverterLong();
    
29. }
    
30. return base.ResolveContractConverter(objectType);
    
31. }
32.  
33. ///// <summary>
    
34. ///// Creates a Newtonsoft.Json.Serialization.JsonProperty for the given System.Reflection.MemberInfo.
    
35. ///// </summary>
    
36. ///// <param name="type"></param>
    
37. ///// <param name="memberSerialization"></param>
    
38. ///// <returns></returns>
    
39. //protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
    
40. //{
    
41. // return type.GetProperties()
    
42. // .Select(p =>
    
43. // {
    
44. // var jp = base.CreateProperty(p, memberSerialization);
    
45. // jp.ValueProvider = new NullToEmptyStringValueProvider(p);
    
46. // return jp;
    
47. // }).ToList();
    
48. //}
    
49. }
    
50. }

　　

1. using Newtonsoft.Json;
   
2. using System;
   
3. using System.Collections.Generic;
   
4. using System.Text;
5.  
6. namespace NetCore3WebApiTemplate.Utility
   
7. {
   
8. /// <summary>
   
9. /// Long类型Json序列化重写
   
10. /// 在js中传输会导致精度丢失，故而在序列化时转换成字符类型
    
11. /// </summary>
    
12. public class JsonConverterLong : JsonConverter
    
13. {
    
14. /// <summary>
    
15. /// 是否可以转换
    
16. /// </summary>
    
17. /// <param name="objectType"></param>
    
18. /// <returns></returns>
    
19. public override bool CanConvert(Type objectType)
    
20. {
    
21. return true;
    
22. }
23.  
24. /// <summary>
    
25. /// 读json
    
26. /// </summary>
    
27. /// <param name="reader"></param>
    
28. /// <param name="objectType"></param>
    
29. /// <param name="existingValue"></param>
    
30. /// <param name="serializer"></param>
    
31. /// <returns></returns>
    
32. public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    
33. {
    
34. if ((reader.ValueType == null || reader.ValueType == typeof(long?)) && reader.Value == null)
    
35. {
    
36. return null;
    
37. }
    
38. else
    
39. {
    
40. long.TryParse(reader.Value != null ? reader.Value.ToString() : "", out long value);
    
41. return value;
    
42. }
    
43. }
44.  
45. /// <summary>
    
46. /// 写json
    
47. /// </summary>
    
48. /// <param name="writer"></param>
    
49. /// <param name="value"></param>
    
50. /// <param name="serializer"></param>
    
51. public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    
52. {
    
53. if (value == null)
    
54. writer.WriteValue(value);
    
55. else
    
56. writer.WriteValue(value + "");
    
57. }
    
58. }
    
59. }

在startup的ConfigureServices中设置

序列化的格式

1. options.SerializerSettings.ContractResolver = new CustomContractResolver();
2.  
3. 时间格式：

1. options.SerializerSettings.DateFormatString = "yyyy'-'MM'-'dd' 'HH':'mm':'ss";

1. 代码如下：

1. /// <summary>
   
2. /// This method gets called by the runtime. Use this method to add services to the container.
   
3. /// </summary>
   
4. /// <param name="services"></param>
   
5. public void ConfigureServices(IServiceCollection services)
   
6. {
   
7. services.AddControllers(ops =>
   
8. {
9.  
10. }).SetCompatibilityVersion(CompatibilityVersion.Version_3_0)
    
11. .AddNewtonsoftJson(options =>
    
12. {
    
13. //设置时间格式
    
14. options.SerializerSettings.DateFormatString = "yyyy'-'MM'-'dd' 'HH':'mm':'ss";
    
15. options.SerializerSettings.ContractResolver = new CustomContractResolver();
    
16. });
    
17. }

　　

注意：

1. AddNewtonsoftJson 方法需要应用Microsoft.AspNetCore.Mvc.NewtonsoftJson
1. https://www.shuzhiduo.com/A/q4zVxXex5K/