RuoYi.Net后端返回雪花ID前端精度丢失问题

遇到问题：

RuoYi.Net 使用 Oracle库，SYS_MENU 菜单表的 MENU_ID 创建为 NUMBER(19) 类型，Vue 前端新增菜单保存到数据库的 MENU_ID ，以及后端返回给前端的 MENU_ID 没问题（ORM 使用的是SqlSugar，SqlSugar 新增入库时如果主键为 long 类型则自动生成雪花ID），但在前端显示时发现精度丢失，如下：

数据库中 MENUID 为 1978349139955683328

前端显示 MENUID 为 1978349139955683300

解决办法：

参见 SqlSugar 官网： https://www.donet5.com/Doc/8nuge/2561

或者在 RuoYi.Admin\Startup.cs 中，修改如下代码：

csharp 复制代码

 .AddNewtonsoftJson(options =>
 {
     // 忽略循环引用
     options.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
     options.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm:ss";

     // 忽略所有 null 属性
     //options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore;
     // long 类型序列化时转 string, 防止 JavaScript 出现精度溢出问题
     options.SerializerSettings.Converters.AddLongTypeConverters(); // 这一行扩展方法
 })

RuoYi.Framework\JsonSerialization\Extensions\NewtonsoftJsonExtensions.cs，如下：

csharp 复制代码

using RuoYi.Framework.JsonSerialization;

namespace Newtonsoft.Json;

/// <summary>
/// Newtonsoft.Json 拓展
/// </summary>
[SuppressSniffer]
public static class NewtonsoftJsonExtensions
{
    /// <summary>
    /// 添加 DateTime/DateTime?/DateTimeOffset/DateTimeOffset? 类型序列化处理
    /// </summary>
    /// <param name="converters"></param>
    /// <param name="outputFormat"></param>
    /// <param name="localized">自动转换 DateTimeOffset 为当地时间</param>
    /// <returns></returns>
    public static IList<JsonConverter> AddDateTimeTypeConverters(this IList<JsonConverter> converters, string outputFormat = "yyyy-MM-dd HH:mm:ss", bool localized = false)
    {
        converters.Add(new NewtonsoftJsonDateTimeJsonConverter(outputFormat));
        converters.Add(new NewtonsoftNullableJsonDateTimeJsonConverter(outputFormat));

        converters.Add(new NewtonsoftJsonDateTimeOffsetJsonConverter(outputFormat, localized));
        converters.Add(new NewtonsoftJsonNullableDateTimeOffsetJsonConverter(outputFormat, localized));

        return converters;
    }

    /// <summary>
    /// 添加 long/long? 类型序列化处理
    /// </summary>
    /// <param name="converters"></param>
    /// <param name="overMaxLengthOf17">是否超过最大长度 17 再处理</param>
    /// <remarks></remarks>
    public static IList<JsonConverter> AddLongTypeConverters(this IList<JsonConverter> converters, bool overMaxLengthOf17 = false)
    {
        converters.Add(new NewtonsoftJsonLongToStringJsonConverter(overMaxLengthOf17));
        converters.Add(new NewtonsoftJsonNullableLongToStringJsonConverter(overMaxLengthOf17));

        return converters;
    }

    /// <summary>
    /// 添加 DateOnly/DateOnly? 类型序列化处理
    /// </summary>
    /// <param name="converters"></param>
    /// <returns></returns>
    public static IList<JsonConverter> AddDateOnlyConverters(this IList<JsonConverter> converters)
    {
#if !NET5_0
        converters.Add(new NewtonsoftJsonDateOnlyJsonConverter());
        converters.Add(new NewtonsoftJsonNullableDateOnlyJsonConverter());
#endif
        return converters;
    }

    /// <summary>
    /// 添加 TimeOnly/TimeOnly? 类型序列化处理
    /// </summary>
    /// <param name="converters"></param>
    /// <returns></returns>
    public static IList<JsonConverter> AddTimeOnlyConverters(this IList<JsonConverter> converters)
    {
#if !NET5_0
        converters.Add(new NewtonsoftJsonTimeOnlyJsonConverter());
        converters.Add(new NewtonsoftJsonNullableTimeOnlyJsonConverter());
#endif
        return converters;
    }
}

RuoYi.Framework\JsonSerialization\Converters\NewtonsoftJson\NewtonsoftJsonLongToStringJsonConverter.cs，如下：

csharp 复制代码

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace RuoYi.Framework.JsonSerialization;

/// <summary>
/// 解决 long 精度问题
/// </summary>
[SuppressSniffer]
public class NewtonsoftJsonLongToStringJsonConverter : JsonConverter<long>
{
    /// <summary>
    /// 构造函数
    /// </summary>
    public NewtonsoftJsonLongToStringJsonConverter()
    {
    }

    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="overMaxLengthOf17"></param>
    public NewtonsoftJsonLongToStringJsonConverter(bool overMaxLengthOf17 = false)
    {
        OverMaxLengthOf17 = overMaxLengthOf17;
    }

    /// <summary>
    /// 是否超过最大长度 17 再处理
    /// </summary>
    public bool OverMaxLengthOf17 { get; set; }

    /// <summary>
    /// 反序列化
    /// </summary>
    /// <param name="reader"></param>
    /// <param name="objectType"></param>
    /// <param name="existingValue"></param>
    /// <param name="hasExistingValue"></param>
    /// <param name="serializer"></param>
    /// <returns></returns>
    public override long ReadJson(JsonReader reader, Type objectType, long existingValue, bool hasExistingValue, JsonSerializer serializer)
    {
        var jt = JValue.ReadFrom(reader);
        return jt.Value<long>();
    }

    /// <summary>
    /// 序列化
    /// </summary>
    /// <param name="writer"></param>
    /// <param name="value"></param>
    /// <param name="serializer"></param>
    public override void WriteJson(JsonWriter writer, long value, JsonSerializer serializer)
    {
        if (OverMaxLengthOf17)
        {
            if (value.ToString().Length <= 17) writer.WriteValue(value);
            else writer.WriteValue(value.ToString());
        }
        else writer.WriteValue(value.ToString());
    }
}

/// <summary>
/// 解决 long? 精度问题
/// </summary>
[SuppressSniffer]
public class NewtonsoftJsonNullableLongToStringJsonConverter : JsonConverter<long?>
{
    /// <summary>
    /// 构造函数
    /// </summary>
    public NewtonsoftJsonNullableLongToStringJsonConverter()
    {
    }

    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="overMaxLengthOf17"></param>
    public NewtonsoftJsonNullableLongToStringJsonConverter(bool overMaxLengthOf17 = false)
    {
        OverMaxLengthOf17 = overMaxLengthOf17;
    }

    /// <summary>
    /// 是否超过最大长度 17 再处理
    /// </summary>
    public bool OverMaxLengthOf17 { get; set; }

    /// <summary>
    /// 反序列化
    /// </summary>
    /// <param name="reader"></param>
    /// <param name="objectType"></param>
    /// <param name="existingValue"></param>
    /// <param name="hasExistingValue"></param>
    /// <param name="serializer"></param>
    /// <returns></returns>
    public override long? ReadJson(JsonReader reader, Type objectType, long? existingValue, bool hasExistingValue, JsonSerializer serializer)
    {
        var jt = JValue.ReadFrom(reader);
        return jt.Value<long?>();
    }

    /// <summary>
    /// 序列化
    /// </summary>
    /// <param name="writer"></param>
    /// <param name="value"></param>
    /// <param name="serializer"></param>
    public override void WriteJson(JsonWriter writer, long? value, JsonSerializer serializer)
    {
        if (value == null) writer.WriteNull();
        else
        {
            var newValue = value.Value;
            if (OverMaxLengthOf17)
            {
                if (newValue.ToString().Length <= 17) writer.WriteValue(newValue);
                else writer.WriteValue(newValue.ToString());
            }
            else writer.WriteValue(newValue.ToString());
        }
    }
}