MyBatis一級快取 二級快取

一級快取

在baseexecutor裡面會存放乙個perpetualcache 作為一級快取，當update，commit，rollback都會呼叫clearlocalcache（）方法清理一級快取。

public

abstract
class
baseexecutor
implements
executor
@suppresswarnings
("unchecked"
)@override
public
list
query
cachekey key, boundsql boundsql)
throws sqlexception 
if(querystack ==
0&& ms.
isflushcacherequired()
) list
list;
tryelse
}finally
if(querystack ==0)
// issue #601
// 清空deferredloads
deferredloads.
clear()
;if(configuration.
getlocalcachescope()
== localcachescope.statement)
}return list;
}private
list
queryfromdatabase
resulthandler resulthandler, cachekey key, boundsql boundsql)
throws sqlexception 
finally
// 新增到快取中
localcache.
putobject
(key, list);if
(ms.
getstatementtype()
== statementtype.callable)
return list;
}@override
public
intupdate
throws sqlexception 
clearlocalcache()
;return
doupdate
(ms, parameter);}
@override
public
void
commit
(boolean required)
throws sqlexception 
clearlocalcache()
;flushstatements()
;if(required)
}@override
public
void
rollback
(boolean required)
throws sqlexception 
finally}}
}@override
public
void
clearlocalcache()
}}

配置 mybatis.configuration.cache-enabled=true，只要沒有顯式地設定cacheenabled=false，都會用cachingexecutor

public

class
configuration

public

class
xmlstatementbuilder
extends
basebuilder
public
class
xnode
else
}}

public

class
defaultsqlsessionfactory
implements
sqlsessionfactory
catch
(exception e)
finally
}}

public

class
configuration
else
if(executortype.reuse == executortype)
else
// 如果開啟快取（預設是開啟的），則使用快取執行器
if(cacheenabled)
// 外掛程式執行
executor =
(executor) interceptorchain.
pluginall
(executor)
;return executor;
}}

public

class
defaultsqlsession
implements
sqlsession
catch
(exception e)
finally
}}

public

class
cachingexecutor
implements
executor
@override
public
list
query
throws sqlexception 
@override
public
list
query
throws sqlexception 
return list;}}
// 委託給baseexecutor執行
return delegate.
query
(ms, parameterobject, rowbounds, resulthandler, key, boundsql);}
@override
public
intupdate
throws sqlexception 
//刪除快取
private
void
flushcacheifrequired
}}

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