.NET如何使用Entity Framework Core进行读写分离_EF Core读写分离配置

{
  "ConnectionStrings": {
    "MasterDb": "Server=localhost;Database=MyAppDb;User=sa;Password=...;",
    "SlaveDb": "Server=replica-host;Database=MyAppDb;User=sa;Password=...;"
  }
}

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions options) : base(options) { }

    public DbSet Users { get; set; }
    // 其他 DbSet...
}

builder.Services.AddScoped(sp =>
    new AppDbContext(new DbContextOptionsBuilder()
        .UseSqlServer(builder.Configuration.GetConnectionString("MasterDb"))
        .Options));

builder.Services.AddScoped(sp =>
    new AppDbContext(new DbContextOptionsBuilder()
        .UseSqlServer(builder.Configuration.GetConnectionString("SlaveDb"))
        .Options));

builder.Services.AddDbContext(options => 
    options.UseSqlServer(builder.Configuration.GetConnectionString("MasterDb")));

builder.Services.AddDbContext(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("SlaveDb")));

public class UserService
{
    private readonly AppDbContext _writeContext;
    private readonly ReadOnlyAppDbContext _readContext;

    public UserService(AppDbContext writeContext, ReadOnlyAppDbContext readContext)
    {
        _writeContext = writeContext;
        _readContext = readContext;
    }

    public async Task GetUserById(int id)
    {
        // 读操作走从库
        return await _readContext.Users.FindAsync(id);
    }

    public async Task AddUser(User user)
    {
        // 写操作走主库
        await _writeContext.Users.AddAsync(user);
        await _writeContext.SaveChangesAsync();
    }
}