Detailed explanation of setting configuration examples in java mybatis

This article mainly introduces you to the relevant information about setting configuration in mybatis. The article introduces it in great detail through sample code, which has certain reference and learning value for everyone. Friends who need it can take a look below.

In mybaits, the setting configuration parameters are as follows (if not configured in the configuration file , the default value will be used):

##defaultFetchSizeSets the driver a hint as to control fetching size for Any positive integerNot Set (null)safeRowBoundsEnabledAllows the use of paging (RowBounds) in nested statements. true | falseFalse##mapUnderscoreToCamelCaselocalCacheScopeSESSIONjdbcTypeForNulllazyLoadTriggerMethods##defaultScriptingLanguageSpecify dynamic SQL generated default language. A type alias or fully qualified class name.org.apache.ibatis.scripting.xmltags.XMLDynamicLanguageDrivercallSettersOnNullsSpecify whether to call the setter (put for map object) method of the mapping object when the value in the result set is null. This is useful when there is Map.keySet() dependency or null value initialization. Note that basic types (int, boolean, etc.) cannot be set to null. true | falsefalselogPrefixSpecify the prefix that MyBatis adds to the log name. Any StringNot setlogImplSpecify the specific implementation of the log used by MyBatis. If not specified, it will be searched automatically.

Set parameters	Description	Valid values	Default value
cacheEnabled	Global switch for cache configured in all mappers affected by this configuration	true | false	true
lazyLoadingEnabled	Global switch for lazy loading. When enabled, all associated objects will be loaded lazily. In a specific association, the switch state of the item can be overridden by setting the fetchType attribute	true | false	false
aggressiveLazyLoading	When enabled, calls to any lazy attribute will cause objects with lazy loading attributes to be fully loaded; otherwise, each attribute will be loaded on demand.	true | false	true
multipleResultSetsEnabled	Whether a single statement is allowed to return multiple result sets (requires compatible driver).	true | false	true
useColumnLabel	Use column labels instead of column names. Different drivers will have different performances in this regard. For details, you can refer to the relevant driver documentation or observe the results of the driver used by testing these two different modes.	true | false	true
useGeneratedKeys	Allows JDBC to support automatic generation of primary keys and requires driver compatibility. If set to true this setting forces the use of auto-generated primary keys, which will work even if some drivers are incompatible (e.g. Derby).	true | false	False
autoMappingBehavior	Specifies how MyBatis should automatically map columns to fields or properties. NONE means to cancel automatic mapping; PARTIAL will only automatically map result sets that do not define nested result set mapping. FULL automatically maps arbitrarily complex result sets (nested or not).	NONE, PARTIAL, FULL	PARTIAL
defaultExecutorType	Configure the default executor. SIMPLE is an ordinary executor; the REUSE executor will reuse prepared statements; the BATCH executor will reuse statements and perform batch updates.	SIMPLE REUSE BATCH	SIMPLE
defaultStatementTimeout	Set the timeout, which determines the number of seconds the driver waits for a database response.	Any positive integer	Not Set (null)
	return results. This parameter value can be override by a query setting.
Whether to turn on the automatic camel case naming rule (camel case) mapping, that is, from the classic Similar mapping of database column name A_COLUMN to classic Java property name aColumn.	true | false	False
MyBatis uses the local cache mechanism (Local Cache) to prevent circular references ) and speed up repeated nested queries. The default value is	, in which case all queries executed within a session are cached. If set to STATEMENT, the local session is used only for statement execution, and different calls to the same SqlSession will not share data. SESSION | STATEMENT	SESSION
When no specific JDBC type is provided for the parameter, a null value is specified. JDBC type. Some drivers need to specify the JDBC type of the column. In most cases, just use the general type, such as NULL, VARCHAR or OTHER.	JdbcType enumeration. Most common are: NULL, VARCHAR and OTHER	OTHER
Specify which object method to trigger A lazy load.	A method name list separated by commas	equals,clone,hashCode,toString
SLF4J | LOG4J | LOG4J2 | JDK_LOGGING | COMMONS_LOGGING | STDOUT_LOGGING | NO_LOGGING	Not set
proxyFactory	Specify Mybatis to create a Proxy tool used for objects with lazy loading capabilities.	CGLIB | JAVASSIST	JAVASSIST (MyBatis 3.3 or above)

##In actual applications, you must configure it according to your own needs:

For example, my configuration in the project is generally as follows:

<settings>

<setting name="jdbcTypeForNull" value="NULL" />

<setting name="logImpl" value="SLF4J" />

<setting name="mapUnderscoreToCamelCase" value="true" />

<setting name="defaultExecutorType" value="BATCH" />

</settings>

Note: The log4j log of some configurations cannot be printed. When issuing a sql statement, not only should you check the log4j configuration file, but also the configuration of name="logImpl" value="SLF4J" />
should be specified. (If you are using LOG4J), for example:

<configuration> 
 <settings> 
 <setting name="logImpl" value="LOG4J"/> 
 </settings> 
</configuration>

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