(精华)2020年10月18日 高可用高并发 缓存的使用(Sqlserver)

首先安装缓存数据包

dotnet tool install --global dotnet-sql-cache

执行

dotnet sql-cache create 数据库连接字符串 dbo 缓存数据表名称

nutget 安装如下包

Microsoft.Extensions.Caching.SqlServer

配置

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDistributedSqlServerCache(options =>
            {
                // 缓存过期扫描时钟
                options.SystemClock = new LocalSystemClock();
                // 连接字符串
                options.ConnectionString = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=EFCoreSample;Integrated Security=True;";
                // 架构名称
                options.SchemaName = "dbo";
                // 缓存表名
                options.TableName = "TestCache";
                // 缓存过期时间1分钟，默认20分钟
                options.DefaultSlidingExpiration = TimeSpan.FromMinutes(1);
	        });
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }

public class LocalSystemClock : ISystemClock
    {
        public DateTimeOffset UtcNow => DateTime.Now;
    }

使用

[Route("api/[controller]")]
    [ApiController]
    public class Sample01Controller : ControllerBase
    {
        private readonly IDistributedCache _cache;

        public Sample01Controller(IDistributedCache distributedCache)
        {
            _cache = distributedCache;
        }

        public async Task<IActionResult> Get()
        {
            var cacheTime = await _cache.GetStringAsync("CacheTime");
            if (cacheTime == null)
            {
                cacheTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss");
                await _cache.SetAsync("CacheTime", Encoding.UTF8.GetBytes(cacheTime));
            }

            return Ok(new
            {
                cacheTime,
                currentTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss")
            });
        }
    }

[Route("api/[controller]")]
    [ApiController]
    public class Sample02Controller : ControllerBase
    {
        private readonly IDistributedCache _cache;

        public Sample02Controller(IDistributedCache distributedCache)
        {
            _cache = distributedCache;
        }

        public async Task<IActionResult> Get()
        {
            var cacheTime = await _cache.GetStringAsync("CacheTime");
            if (cacheTime == null)
            {
                cacheTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss");
                var cacheEntryOptions = new DistributedCacheEntryOptions()
                    .SetSlidingExpiration(TimeSpan.FromSeconds(10))
                    .SetAbsoluteExpiration(TimeSpan.FromSeconds(20));

                await _cache.SetAsync("CacheTime", Encoding.UTF8.GetBytes(cacheTime), cacheEntryOptions);
            }

            return Ok(new
            {
                cacheTime,
                currentTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss")
            });
        }
    }