mybaties基础教程之三：MyBatis主配置文件

灰太狼 2023-10-16 19:46 16阅读 0赞

MyBatis配置文件中大标签configuration下子标签包括：

configuration

|--- properties

|--- settings

|--- typeAliases

|--- typeHandlers

|--- objectFactory

|--- plugins

|--- environments

|--- |--- environment

|--- |--- |--- transactionManager

|--- |--- |\_\_ dataSource

|\_\_ mappers

### 3.1 properties属性 ###

properties和java的.properties的配置文件有关。配置properties的resource指定.properties的路径，然后再在properties标签下配置property的name和value，则可以替换.properties文件中相应属性值。

<properties resource="mysql.properties">
 	<property name="jdbc.driverClassName" value="com.mysql.jdbc.Driver"/>
 	<property name="jdbc.url" value="jdbc:mysql://localhost:3306/student_manager"/>
 	<property name="username" value="root"/>
 	<property name="password" value="limingnihao"/>
 </properties>

### 3.2 settings设置 ###

这是MyBatis 修改操作运行过程细节的重要的步骤。下方这个表格描述了这些设置项、含义和默认值。

<table style="border:currentColor; border-collapse:collapse"> 
 <tbody> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt"> 设置项 </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-left-color:currentColor; border-left-width:medium; border-left-style:none"> 描述 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-left-color:currentColor; border-left-width:medium; border-left-style:none"> 允许值 </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-left-color:currentColor; border-left-width:medium; border-left-style:none"> 默认值 </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> cacheEnabled </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 对在此配置文件下的所有cache 进行全局性开/关设置。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true | false </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> lazyLoadingEnabled </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 全局性设置懒加载。如果设为‘false’，则所有相关联的都会被初始化加载。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true | false </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> aggressiveLazyLoading </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 当设置为‘true’的时候，懒加载的对象可能被任何懒属性全部加载。否则，每个属性都按需加载。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true | false </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> multipleResultSetsEnabled </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 允许和不允许单条语句返回多个数据集（取决于驱动需求） </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true | false </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> useColumnLabel </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 使用列标签代替列名称。不同的驱动器有不同的作法。参考一下驱动器文档，或者用这两个不同的选项进行测试一下。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true | false </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> useGeneratedKeys </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 允许JDBC 生成主键。需要驱动器支持。如果设为了true，这个设置将强制使用被生成的主键，有一些驱动器不兼容不过仍然可以执行。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> true | false </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> false </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> autoMappingBehavior </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 指定MyBatis 是否并且如何来自动映射数据表字段与对象的属性。PARTIAL将只自动映射简单的，没有嵌套的结果。FULL将自动映射所有复杂的结果。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> NONE, PARTIAL, FULL </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> PARTIAL </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> defaultExecutorType </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 配置和设定执行器，SIMPLE 执行器执行其它语句。REUSE执行器可能重复使用prepared statements 语句，BATCH执行器可以重复执行语句和批量更新。 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> SIMPLE REUSE BATCH </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> SIMPLE </td> 
 </tr> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:125.6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> defaultStatementTimeout </td> 
 <td style="padding:0cm 5.4pt; width:369pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 设置一个时限，以决定让驱动器等待数据库回应的多长时间为超时 </td> 
 <td style="padding:0cm 5.4pt; width:90pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 正整数 </td> 
 <td style="padding:0cm 5.4pt; width:63pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Not Set (null) </td> 
 </tr> 
 </tbody> 
</table>

例如：

### 3.3 typeAliases类型别名 ###

类型别名是Java 类型的简称。

它仅仅只是关联到XML 配置，简写冗长的JAVA 类名。例如：

使用这个配置，“StudentEntity”就能在任何地方代替“com.manager.data.model.StudentEntity”被使用。

对于普通的Java类型，有许多内建的类型别名。它们都是大小写不敏感的，由于重载的名字，要注意原生类型的特殊处理。

<table style="border:currentColor; border-collapse:collapse"> 
 <tbody> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:213.05pt"> 别名 </td> 
 <td style="padding:0cm 5.4pt; width:213.05pt; border-left-color:currentColor; border-left-width:medium; border-left-style:none"> 映射的类型 </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _byte </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> byte </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _long </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> long </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _short </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> short </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _int </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> int </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _integer </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> int </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _double </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> double </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _float </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> float </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> _boolean </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> boolean </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> string </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> String </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> byte </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Byte </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> long </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Long </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> short </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Short </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> int </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Integer </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> integer </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Integer </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> double </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Double </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> float </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Float </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> boolean </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Boolean </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> date </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Date </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> decimal </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> BigDecimal </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> bigdecimal </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> BigDecimal </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> object </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Object </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> map </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Map </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> hashmap </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> HashMap </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> list </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> List </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> arraylist </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> ArrayList </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> collection </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Collection </td> 
 </tr> 
 <tr style="height:4.75pt"> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> iterator </td> 
 <td style="padding:0cm 5.4pt; height:4.75pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Iterator </td> 
 </tr> 
 </tbody> 
</table>

### 3.4 typeHandlers类型句柄 ###

无论是MyBatis在预处理语句中设置一个参数，还是从结果集中取出一个值时，类型处理器被用来将获取的值以合适的方式转换成Java类型。下面这个表格描述了默认的类型处理器。

<table style="border:currentColor; border-collapse:collapse"> 
 <tbody> 
 <tr> 
 <td style="padding:0cm 5.4pt; width:142pt"> 类型处理器 </td> 
 <td style="padding:0cm 5.4pt; width:142.05pt; border-left-color:currentColor; border-left-width:medium; border-left-style:none"> Java类型 </td> 
 <td style="padding:0cm 5.4pt; width:319.2pt; border-left-color:currentColor; border-left-width:medium; border-left-style:none"> JDBC类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> BooleanTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Boolean，boolean </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的布尔值 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> ByteTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Byte，byte </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字或字节类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> ShortTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Short，short </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字或短整型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> IntegerTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Integer，int </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字和整型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> LongTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Long，long </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字或长整型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> FloatTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Float，float </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字或单精度浮点型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> DoubleTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Double，double </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字或双精度浮点型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> BigDecimalTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> BigDecimal </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的数字或十进制小数类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> StringTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> String </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> CHAR和VARCHAR类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> ClobTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> String </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> CLOB和LONGVARCHAR类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> NStringTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> String </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> NVARCHAR和NCHAR类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> NClobTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> String </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> NCLOB类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> ByteArrayTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> byte[] </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 任何兼容的字节流类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> BlobTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> byte[] </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> BLOB和LONGVARBINARY类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> DateTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Date（java.util） </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> TIMESTAMP类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> DateOnlyTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Date（java.util） </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> DATE类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> TimeOnlyTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Date（java.util） </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> TIME类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> SqlTimestampTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Timestamp（java.sql） </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> TIMESTAMP类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> SqlDateTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Date（java.sql） </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> DATE类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> SqlTimeTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Time（java.sql） </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> TIME类型 </td> 
 </tr> 
 <tr style="height:6pt"> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> ObjectTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Any </td> 
 <td style="padding:0cm 5.4pt; height:6pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> 其他或未指定类型 </td> 
 </tr> 
 <tr style="height:13.1pt"> 
 <td style="padding:0cm 5.4pt; height:13.1pt; border-top-color:currentColor; border-top-width:medium; border-top-style:none"> EnumTypeHandler </td> 
 <td style="padding:0cm 5.4pt; height:13.1pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> Enumeration类型 </td> 
 <td style="padding:0cm 5.4pt; height:13.1pt; border-top-color:currentColor; border-left-color:currentColor; border-top-width:medium; border-left-width:medium; border-top-style:none; border-left-style:none"> VARCHAR-任何兼容的字符串类型，作为代码存储（而不是索引）。 </td> 
 </tr> 
 </tbody> 
</table>

你可以重写类型处理器或创建你自己的类型处理器来处理不支持的或非标准的类型。要这样做的话，简单实现TypeHandler接口（org.mybatis.type），然后映射新的类型处理器类到Java类型，还有可选的一个JDBC类型。然后再typeHandlers中添加这个类型处理器。

新定义的类型处理器将会覆盖已经存在的处理Java的String类型属性和VARCHAR参数及结果的类型处理器。要注意MyBatis不会审视数据库元信息来决定使用哪种类型，所以你必须在参数和结果映射中指定那是VARCHAR类型的字段，来绑定到正确的类型处理器上。这是因为MyBatis直到语句被执行都不知道数据类型的这个现实导致的。

public class LimingStringTypeHandler implements TypeHandler {
    
    	@Override
    	public void setParameter(PreparedStatement ps, int i, Object parameter, JdbcType jdbcType) throws SQLException {
    		System.out.println("setParameter - parameter: " + ((String) parameter) + ", jdbcType: " + jdbcType.TYPE_CODE);
    		ps.setString(i, ((String) parameter));
    	}
    
    	@Override
    	public Object getResult(ResultSet rs, String columnName) throws SQLException {
    		System.out.println("getResult - columnName: " + columnName);
    		return rs.getString(columnName);
    	}
    
    	@Override
    	public Object getResult(CallableStatement cs, int columnIndex) throws SQLException {
    		System.out.println("getResult - columnIndex: " + columnIndex);
    		return cs.getString(columnIndex);
    	}
    }

在配置文件的typeHandlers中添加typeHandler标签。

### 3.5 ObjectFactory对象工厂 ###

每次MyBatis 为结果对象创建一个新实例，都会用到ObjectFactory。默认的ObjectFactory 与使用目标类的构造函数创建一个实例毫无区别，如果有已经映射的参数，那也可能使用带参数的构造函数。

如果你重写ObjectFactory 的默认操作，你可以通过继承org.apache.ibatis.reflection.factory.DefaultObjectFactory创建一下你自己的。

ObjectFactory接口很简单。它包含两个创建用的方法，一个是处理默认构造方法的，另外一个是处理带参数构造方法的。最终，setProperties方法可以被用来配置ObjectFactory。在初始化你的ObjectFactory实例后，objectFactory元素体中定义的属性会被传递给setProperties方法。

public class LimingObjectFactory extends DefaultObjectFactory {
 
 	private static final long serialVersionUID = -399284318168302833L;
 
 	@Override
 	public Object create(Class type) {
 		return super.create(type);
 	}
 
 	@Override
 	public Object create(Class type, List<Class> constructorArgTypes, List<Object> constructorArgs) {
 		System.out.println("create - type: " + type.toString());
 		return super.create(type, constructorArgTypes, constructorArgs);
 	}
 
 	@Override
 	public void setProperties(Properties properties) {
 		System.out.println("setProperties - properties: " + properties.toString() + ", someProperty: " + properties.getProperty("someProperty"));
 		super.setProperties(properties);
 	}
 
 }

配置文件中添加objectFactory标签

### 3.6 plugins插件 ###

MyBatis允许你在某一点拦截已映射语句执行的调用。默认情况下，MyBatis允许使用插件来拦截方法调用：

*  Executor(update, query, flushStatements,commit, rollback, getTransaction, close, isClosed)
 *  ParameterHandler(getParameterObject,setParameters)
 *  ResultSetHandler(handleResultSets,handleOutputParameters)
 *  StatementHandler(prepare, parameterize,batch, update, query)

这些类中方法的详情可以通过查看每个方法的签名来发现，而且它们的源代码在MyBatis的发行包中有。你应该理解你覆盖方法的行为，假设你所做的要比监视调用要多。如果你尝试修改或覆盖一个给定的方法，你可能会打破MyBatis的核心。这是低层次的类和方法，要谨慎使用插件。

使用插件是它们提供的非常简单的力量。简单实现拦截器接口，要确定你想拦截的指定签名。

### 3.7 environments环境 ###

MyBatis 可以配置多个环境。这可以帮助你SQL 映射对应多种数据库等。

### 3.8 mappers映射器 ###

这里是告诉MyBatis 去哪寻找映射SQL 的语句。可以使用类路径中的资源引用，或者使用字符，输入确切的URL引用。

例如：