springboot用javaConfig写Mybatis自定义配置

springboot主张用java config代替xml配置，但在大部分博文中依然用的是xml配置讲解，很少讲解javaConfig的内容，我这里记录下自己用java config配置mybatis。

pom.xml就不多说了，日常引入

mybatis-spring-boot-starter

这个当然也可以自动加载mybatis的配置，但是在一般大项目中，自动的那些默认配置就很难满足了。

mybatis javaConfig如下：

@Configuration
@ConfigurationProperties(prefix = "mybatis")
@PropertySource("application-mybatis.yml")
public class MyBatisConfig {

    private static final Logger logger = Logger.getLogger(MyBatisConfig.class);

//    @Autowired
//    private Environment env;

    @Autowired
    private DataSource druidDataSource;


    @Value("${mapperLocations}")
    private String mapperLocations;

    @Value("${default-statement-timeout}")
    private int dst;

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception{
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
        logger.info("sqlSessionFactory:--->mybatis.mapperLocation:" + mapperLocations );

        sqlSessionFactoryBean.setDataSource(druidDataSource);
        org.apache.ibatis.session.Configuration cfg = new org.apache.ibatis.session.Configuration();//configuration
        cfg.setDefaultStatementTimeout(dst);//设置相关参数，我这里就只用了一个
        logger.info("sqlSessionFactoryBean:-->" + sqlSessionFactoryBean.getObject());
        logger.info("default-statement-timeout:" + dst);
        sqlSessionFactoryBean.setConfiguration(cfg);
        return sqlSessionFactoryBean.getObject();
    }

相关configuration参数如下：

settings

These are extremely important tweaks that modify the way that MyBatis behaves at runtime. The following table describes the settings, their meanings and their default values.

Setting	Description	Valid Values	Default
cacheEnabled	Globally enables or disables any caches configured in any mapper under this configuration.	true | false	true
lazyLoadingEnabled	Globally enables or disables lazy loading. When enabled, all relations will be lazily loaded. This value can be superseded for an specific relation by using the fetchType attribute on it.	true | false	false
aggressiveLazyLoading	When enabled, any method call will load all the lazy properties of the object. Otherwise, each property is loaded on demand (see also lazyLoadTriggerMethods).	true | false	false (true in ≤3.4.1)
multipleResultSetsEnabled	Allows or disallows multiple ResultSets to be returned from a single statement (compatible driver required).	true | false	true
useColumnLabel	Uses the column label instead of the column name. Different drivers behave differently in this respect. Refer to the driver documentation, or test out both modes to determine how your driver behaves.	true | false	true
useGeneratedKeys	Allows JDBC support for generated keys. A compatible driver is required. This setting forces generated keys to be used if set to true, as some drivers deny compatibility but still work (e.g. Derby).	true | false	False
autoMappingBehavior	Specifies if and how MyBatis should automatically map columns to fields/properties. NONE disables auto-mapping. PARTIAL will only auto-map results with no nested result mappings defined inside. FULL will auto-map result mappings of any complexity (containing nested or otherwise).	NONE, PARTIAL, FULL	PARTIAL
autoMappingUnknownColumnBehavior	Specify the behavior when detects an unknown column (or unknown property type) of automatic mapping target. NONE: Do nothing WARNING: Output warning log (The log level of 'org.apache.ibatis.session.AutoMappingUnknownColumnBehavior' must be set to WARN) FAILING: Fail mapping (Throw SqlSessionException)	NONE, WARNING, FAILING	NONE
defaultExecutorType	Configures the default executor. SIMPLE executor does nothing special. REUSE executor reuses prepared statements. BATCH executor reuses statements and batches updates.	SIMPLE REUSE BATCH	SIMPLE
defaultStatementTimeout	Sets the number of seconds the driver will wait for a response from the database.	Any positive integer	Not Set (null)
defaultFetchSize	Sets the driver a hint as to control fetching size for return results. This parameter value can be override by a query setting.	Any positive integer	Not Set (null)
safeRowBoundsEnabled	Allows using RowBounds on nested statements. If allow, set the false.	true | false	False
safeResultHandlerEnabled	Allows using ResultHandler on nested statements. If allow, set the false.	true | false	True
mapUnderscoreToCamelCase	Enables automatic mapping from classic database column names A_COLUMN to camel case classic Java property names aColumn.	true | false	False
localCacheScope	MyBatis uses local cache to prevent circular references and speed up repeated nested queries. By default (SESSION) all queries executed during a session are cached. If localCacheScope=STATEMENT local session will be used just for statement execution, no data will be shared between two different calls to the same SqlSession.	SESSION | STATEMENT	SESSION
jdbcTypeForNull	Specifies the JDBC type for null values when no specific JDBC type was provided for the parameter. Some drivers require specifying the column JDBC type but others work with generic values like NULL, VARCHAR or OTHER.	JdbcType enumeration. Most common are: NULL, VARCHAR and OTHER	OTHER
lazyLoadTriggerMethods	Specifies which Object's methods trigger a lazy load	A method name list separated by commas	equals,clone,hashCode,toString
defaultScriptingLanguage	Specifies the language used by default for dynamic SQL generation.	A type alias or fully qualified class name.	org.apache.ibatis.scripting.xmltags.XMLLanguageDriver
defaultEnumTypeHandler	Specifies the TypeHandler used by default for Enum. (Since: 3.4.5)	A type alias or fully qualified class name.	org.apache.ibatis.type.EnumTypeHandler
callSettersOnNulls	Specifies if setters or map's put method will be called when a retrieved value is null. It is useful when you rely on Map.keySet() or null value initialization. Note primitives such as (int,boolean,etc.) will not be set to null.	true | false	false
returnInstanceForEmptyRow	MyBatis, by default, returns null when all the columns of a returned row are NULL. When this setting is enabled, MyBatis returns an empty instance instead. Note that it is also applied to nested results (i.e. collectioin and association). Since: 3.4.2	true | false	false
logPrefix	Specifies the prefix string that MyBatis will add to the logger names.	Any String	Not set
logImpl	Specifies which logging implementation MyBatis should use. If this setting is not present logging implementation will be autodiscovered.	SLF4J | LOG4J | LOG4J2 | JDK_LOGGING | COMMONS_LOGGING | STDOUT_LOGGING | NO_LOGGING	Not set
proxyFactory	Specifies the proxy tool that MyBatis will use for creating lazy loading capable objects.	CGLIB | JAVASSIST	JAVASSIST (MyBatis 3.3 or above)
vfsImpl	Specifies VFS implementations	Fully qualified class names of custom VFS implementation separated by commas.	Not set
useActualParamName	Allow referencing statement parameters by their actual names declared in the method signature. To use this feature, your project must be compiled in Java 8 with -parameters option. (Since: 3.4.1)	true | false	true
configurationFactory	Specifies the class that provides an instance of Configuration. The returned Configuration instance is used to load lazy properties of deserialized objects. This class must have a method with a signature static Configuration getConfiguration(). (Since: 3.2.3)

至于我的application-mybatis.yml配置文件如何弄，如下：

mybatis:
  mapperLocations: classpath*:mapper*/*.xml
  default-statement-timeout: 30

关于相关资料的查找：

http://www.mybatis.org/mybatis-3/configuration.html#settings

http://www.mybatis.org/spring/apidocs/reference/org/mybatis/spring/package-summary.html