(精华)2020年10月18日 高可用高并发 缓存的使用(Cache)

配置缓存

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

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();
        services.AddMemoryCache(options =>
        {
            options.SizeLimit = 10;//缓存大小
            options.CompactionPercentage = 0.2;//缓存压缩
        });
    }

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

        app.UseRouting();

        app.UseAuthorization();

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

使用
1：基本使用

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

        public Sample01Controller(IMemoryCache memoryCache)
        {
            _cache = memoryCache;
        }

        public IActionResult Get()
        {
            if (!_cache.TryGetValue<string>("CacheTime", out var cacheTime))
            {
                _cache.Set("CacheTime", cacheTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss"));
            }

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

2：过期时间

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

        public Sample02Controller(IMemoryCache memoryCache)
        {
            _cache = memoryCache;
        }

        public IActionResult Get()
        {
            if (!_cache.TryGetValue<string>("CacheTime", out var cacheTime))
            {
                var cacheEntryOptions = new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(TimeSpan.FromSeconds(3));

                _cache.Set("CacheTime", cacheTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss"), cacheEntryOptions);
            }

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

3：绝对过期时间

[Route("api/[controller]")]
    [ApiController]
    public class Sample03Controller : ControllerBase
    {
        private readonly IMemoryCache _cache;

        public Sample03Controller(IMemoryCache memoryCache)
        {
            _cache = memoryCache;
        }

        public IActionResult Get()
        {
            if (!_cache.TryGetValue<string>("CacheTime", out var cacheTime))
            {
                var cacheEntryOptions = new MemoryCacheEntryOptions()
                    .SetSlidingExpiration(TimeSpan.FromSeconds(3))
                    .SetAbsoluteExpiration(TimeSpan.FromSeconds(5));

                _cache.Set("CacheTime", cacheTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss"), cacheEntryOptions);
            }

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

4：缓存大小设置

[Route("api/[controller]")]
    [ApiController]
    public class Sample04Controller : ControllerBase
    {
        private readonly IMemoryCache _cache;

        public Sample04Controller(IMemoryCache memoryCache)
        {
            _cache = memoryCache;
        }

        public IActionResult Get()
        {
            if (!_cache.TryGetValue<string>("CacheTime", out var cacheTime))
            {
                var cacheEntryOptions = new MemoryCacheEntryOptions
                {
                    Size = 100
                };

                _cache.Set("CacheTime", cacheTime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss"), cacheEntryOptions);
            }

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

5：缓存优先级

[Route("api/[controller]")]
    [ApiController]
    public class Sample05Controller : ControllerBase
    {
        private readonly IMemoryCache _cache;

        public Sample05Controller(IMemoryCache memoryCache)
        {
            _cache = memoryCache;
        }

        public IActionResult Get()
        {

            for (var i = 1; i <= 5; i++)
            {
                var cacheEntryOptions = new MemoryCacheEntryOptions
                {
                    Priority = CacheItemPriority.Low,
                    Size = 1
                };
                _cache.Set(i, i.ToString(), cacheEntryOptions);
            }

            for (var i = 6; i <= 10; i++)
            {
                var cacheEntryOptions = new MemoryCacheEntryOptions
                {
                    Priority = CacheItemPriority.Normal,
                    Size = 1
                };
                _cache.Set(i, i.ToString(), cacheEntryOptions);
            }

            {
                var cacheEntryOptions = new MemoryCacheEntryOptions
                {
                    Priority = CacheItemPriority.High,
                    Size = 1
                };
                _cache.Set(11, "11", cacheEntryOptions);
            }

            Console.WriteLine("-------------");
            Console.WriteLine("Key\tValue");
            for (var i = 1; i <= 11; i++)
            {
                Console.WriteLine($"{i}\t{_cache.Get<string>(i) ?? "N/A"}");
            }

            return Ok("ok");
        }
    }

6：综合使用

[Route("api/[controller]")]
    [ApiController]
    public class Sample06Controller : ControllerBase
    {
        private readonly IMemoryCache _cache;

        public Sample06Controller(IMemoryCache memoryCache)
        {
            _cache = memoryCache;
        }

        public IActionResult Get()
        {

            var cacheTime = _cache.GetOrCreate("cacheTime", entry =>
            {
                entry.Priority = CacheItemPriority.Low;
                entry.Size = 1;
                entry.SlidingExpiration = TimeSpan.FromSeconds(3);
                return DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss");
            });

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

文章来源: codeboy.blog.csdn.net，作者：愚公搬代码，版权归原作者所有，如需转载，请联系作者。

原文链接：codeboy.blog.csdn.net/article/details/109150868