/// <summary>
/// 获取缓存
/// </summary>
/// <param name="key">缓存Key</param>
/// <returns></returns>
public static T Get <T>(string key) where T : class
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
return(Cache.Get(key) as T);
}
public void TestMemoryObject()
{
var cache = new Microsoft.Extensions.Caching.Memory.MemoryCache(new MemoryCacheOptions());
cache.Set("user", new User {
Name = "Foo"
});
var f = cache.Get <User>("user");
Assert.Equal("Foo", f.Name);
f.Name = "Bar";
var b = cache.Get <User>("user");
Assert.Equal("Bar", b.Name);
}
protected override Task <T> GetAsync <T>(
CacheKey cacheKey,
CancellationToken cancellationToken)
{
var value = _memoryCache.Get(cacheKey.Value) as T;
return(Task.FromResult(value));
}
public T GetHash <T>(string key, string field)
{
Assert.NotNull(key, nameof(key));
Assert.NotNull(field, nameof(field));
var dicts = _internal.Get <Dictionary <string, object> >(key);
if (dicts != null && dicts.ContainsKey(field))
{
return((T)dicts[field]);
}
return(default(T));
}
/// <summary>
/// 获取存储过程的参数（注意：要链接数据库，高耗费资源的操作）
/// </summary>
/// <param name="procedureName"></param>
/// <param name="dbProviderFactory"></param>
/// <returns></returns>
protected virtual DbParameterCollection GetStoredProcedureParameters(string procedureName, string connectionString, DbProviderFactory dbProviderFactory)
{
if (string.IsNullOrEmpty(procedureName))
{
throw new ArgumentNullException("procedureName");
}
if (string.IsNullOrEmpty(connectionString))
{
throw new ArgumentNullException("connectionString");
}
if (dbProviderFactory == null)
{
throw new ArgumentNullException("dbProviderFactory");
}
string cacheKey = $"DatabaseProcedureParameters_{procedureName}";
DbParameterCollection cachedDbParameterCollection = memoryCache.Get <DbParameterCollection>(cacheKey);
if (cachedDbParameterCollection == null)
{
DbCommand dbCommand = dbProviderFactory.CreateCommand();
dbCommand.CommandType = CommandType.StoredProcedure;
dbCommand.CommandText = procedureName;
using (DbConnection connection = dbProviderFactory.CreateConnection())
{
connection.ConnectionString = connectionString;
connection.Open();
dbCommand.Connection = connection;
DeriveParameters(dbCommand);
connection.Close();
}
cachedDbParameterCollection = dbCommand.Parameters;
#warning 暂时写死5分钟缓存过期
memoryCache.Set(cacheKey, cachedDbParameterCollection, new MemoryCacheEntryOptions()
{
SlidingExpiration = TimeSpan.FromMinutes(5)
});
}
return(cachedDbParameterCollection);
}
public object GetValue(string key)
{
return(_memoryCache.Get(key));
}
public object GetCachedResult(string argument)
{
return(_cache.Get(argument));
}
public override object GetOrDefault(string key)
{
return(_memoryCache.Get(key));
}
public void AddAndReplaceEntries_AreThreadSafe()
{
var cache = new MemoryCache(new MemoryCacheOptions
{
ExpirationScanFrequency = TimeSpan.Zero,
SizeLimit = 20,
CompactionPercentage = 0.5
});
var cts = new CancellationTokenSource();
var random = new Random();
var task0 = Task.Run(() =>
{
while (!cts.IsCancellationRequested)
{
var entrySize = random.Next(0, 5);
cache.Set(random.Next(0, 10), entrySize, new MemoryCacheEntryOptions {
Size = entrySize
});
}
});
var task1 = Task.Run(() =>
{
while (!cts.IsCancellationRequested)
{
var entrySize = random.Next(0, 5);
cache.Set(random.Next(0, 10), entrySize, new MemoryCacheEntryOptions {
Size = entrySize
});
}
});
var task2 = Task.Run(() =>
{
while (!cts.IsCancellationRequested)
{
var entrySize = random.Next(0, 5);
cache.Set(random.Next(0, 10), entrySize, new MemoryCacheEntryOptions {
Size = entrySize
});
}
});
cts.CancelAfter(TimeSpan.FromSeconds(5));
var task3 = Task.Delay(TimeSpan.FromSeconds(7));
Task.WaitAll(task0, task1, task2, task3);
Assert.Equal(TaskStatus.RanToCompletion, task0.Status);
Assert.Equal(TaskStatus.RanToCompletion, task1.Status);
Assert.Equal(TaskStatus.RanToCompletion, task2.Status);
Assert.Equal(TaskStatus.RanToCompletion, task3.Status);
var cacheSize = 0;
for (var i = 0; i < 10; i++)
{
cacheSize += cache.Get <int>(i);
}
Assert.Equal(cacheSize, cache.Size);
Assert.InRange(cache.Count, 0, 20);
}
/// <summary>
/// 获取缓存的数据
/// </summary>
/// <param name="key">关键字</param>
/// <returns></returns>
public object Get(string key)
{
return(memoryCache.Get(key));
}
public void Main()
{
IMemoryCache cache = new MemoryCache(new MemoryCacheOptions());
object result;
string key = "Key";
object newObject = new object();
object state = new object();
// Basic CRUD operations:
// Create / Overwrite
result = cache.Set(key, newObject);
result = cache.Set(key, new object());
// Retrieve, null if not found
result = cache.Get(key);
// Retrieve
bool found = cache.TryGetValue(key, out result);
// Delete
cache.Remove(key);
// Cache entry configuration:
// Stays in the cache as long as possible
result = cache.Set(
key,
new object(),
new MemoryCacheEntryOptions().SetPriority(CacheItemPriority.NeverRemove));
// Automatically remove if not accessed in the given time
result = cache.Set(
key,
new object(),
new MemoryCacheEntryOptions().SetSlidingExpiration(TimeSpan.FromMinutes(5)));
// Automatically remove at a certain time
result = cache.Set(
key,
new object(),
new MemoryCacheEntryOptions().SetAbsoluteExpiration(DateTimeOffset.UtcNow.AddDays(2)));
// Automatically remove at a certain time, which is relative to UTC now
result = cache.Set(
key,
new object(),
new MemoryCacheEntryOptions().SetAbsoluteExpiration(relative: TimeSpan.FromMinutes(10)));
// Automatically remove if not accessed in the given time
// Automatically remove at a certain time (if it lives that long)
result = cache.Set(
key,
new object(),
new MemoryCacheEntryOptions()
.SetSlidingExpiration(TimeSpan.FromMinutes(5))
.SetAbsoluteExpiration(DateTimeOffset.UtcNow.AddDays(2)));
// Callback when evicted
var options = new MemoryCacheEntryOptions()
.RegisterPostEvictionCallback(
(echoKey, value, reason, substate) =>
{
Console.WriteLine(echoKey + ": '" + value + "' was evicted due to " + reason);
});
result = cache.Set(key, new object(), options);
// Remove on token expiration
var cts = new CancellationTokenSource();
options = new MemoryCacheEntryOptions()
.AddExpirationToken(new CancellationChangeToken(cts.Token))
.RegisterPostEvictionCallback(
(echoKey, value, reason, substate) =>
{
Console.WriteLine(echoKey + ": '" + value + "' was evicted due to " + reason);
});
result = cache.Set(key, new object(), options);
// Fire the token to see the registered callback being invoked
cts.Cancel();
// Expire an entry if the dependent entry expires
using (var link = cache.CreateLinkingScope())
{
cts = new CancellationTokenSource();
cache.Set("key1", "value1", new MemoryCacheEntryOptions()
.AddExpirationToken(new CancellationChangeToken(cts.Token)));
// expire this entry if the entry with key "key1" expires.
cache.Set("key2", "value2", new MemoryCacheEntryOptions()
.AddEntryLink(link)
.RegisterPostEvictionCallback(
(echoKey, value, reason, substate) =>
{
Console.WriteLine(echoKey + ": '" + value + "' was evicted due to " + reason);
}));
}
// Fire the token to see the registered callback being invoked
cts.Cancel();
}
