Mybatis全局配置文件详解

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
    <!--mybatis配置...-->
</configuration>

<properties resource="mysql.properties" url=""></properties>

db.url=jdbc:mysql://127.0.0.1:3306/angel_admin?serverTimezone=Asia/Shanghai
db.driver=com.mysql.cj.jdbc.Driver
db.username=root
db.password=123456

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="mysql.properties"/>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <!--驱动名-->
                <property name="driver" value="${db.driver}"/>
                <!--数据库地址-->
                <property name="url"
                          value="${db.url}"/>
                <!--用户名-->
                <property name="username" value="${db.username}"/>
                <!--密码-->
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 添加mapper XML所在文件夹-->
    <mappers>
        <package name="org.pearl.mybatis.demo.dao"/>
    </mappers>
</configuration>

<properties >
    <property name="db.driver" value="com.mysql.cj.jdbc.Driver"/>
    <property name="db.url" value="jdbc:mysql://127.0.0.1:3306/angel_admin?serverTimezone=Asia/Shanghai"/>
    <property name="db.username" value="root"/>
    <property name="db.password" value="123456"/>
</properties>

<properties >
    <!-- 启用默认值特性 -->
    <property name="org.apache.ibatis.parsing.PropertyParser.enable-default-value" value="true"/> 
</properties>

<dataSource type="POOLED">
    <!--驱动名-->
    <property name="driver" value="${db.driver:com.mysql.cj.jdbc.Driver}"/>
    <!--数据库地址-->
    <property name="url"
              value="${db.url:jdbc:mysql://127.0.0.1:3306/angel_admin?serverTimezone=Asia/Shanghai}"/>
    <!--用户名-->
    <property name="username" value="${db.username:root}"/>
    <!--密码-->
    <property name="password" value="${db.password:123456}"/>
</dataSource>

<properties >
    <!--添加自定义默认分隔符-->
    <property name="org.apache.ibatis.parsing.PropertyParser.enable-default-value" value="?:"/>
</properties>

<settings>
  <setting name="cacheEnabled" value="true"/>
  <setting name="lazyLoadingEnabled" value="true"/>
  <setting name="multipleResultSetsEnabled" value="true"/>
  <setting name="useColumnLabel" value="true"/>
  <setting name="useGeneratedKeys" value="false"/>
  <setting name="autoMappingBehavior" value="PARTIAL"/>
  <setting name="autoMappingUnknownColumnBehavior" value="WARNING"/>
  <setting name="defaultExecutorType" value="SIMPLE"/>
  <setting name="defaultStatementTimeout" value="25"/>
  <setting name="defaultFetchSize" value="100"/>
  <setting name="safeRowBoundsEnabled" value="false"/>
  <setting name="mapUnderscoreToCamelCase" value="false"/>
  <setting name="localCacheScope" value="SESSION"/>
  <setting name="jdbcTypeForNull" value="OTHER"/>
  <setting name="lazyLoadTriggerMethods" value="equals,clone,hashCode,toString"/>
</settings>

<!--驼峰命名 自动将数据库字段下划线转为驼峰-->
<setting name="mapUnderscoreToCamelCase" value="true"/>

<select id="selectOneById" resultType="user">
    select * from base_user where user_id = #{id}
</select>

<mapper namespace="org.pearl.mybatis.demo.dao.UserMapper">
    <select id="selectOneById" resultType="org.pearl.mybatis.demo.pojo.entity.User">
    select * from base_user where user_id = #{id}
  </select>
</mapper>

<select id="selectOneById" resultType="user">
    select * from base_user where user_id = #{id}
</select>

<typeAliases>
    <!--单个类起别名-->
    <typeAlias type="org.pearl.mybatis.demo.pojo.entity.User" alias="user"/>
    <!--为某个包起别名 默认别名为类名小写-->
    <package name="org.pearl.mybatis.demo.pojo.entity"/>
</typeAliases>

@Data
@Alias("user")
public class User implements Serializable {}

@MappedJdbcTypes(JdbcType.VARCHAR)
public class ExampleTypeHandler extends BaseTypeHandler<String> {

    /**
     * javaType转换成jdbcTpe
     */
    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, String parameter, JdbcType jdbcType) throws SQLException {
        ps.setString(i, parameter);
    }

    /**
     *  将从结果集根据列名称获取到的数据的jdbcType转换成javaType
     */
    @Override
    public String getNullableResult(ResultSet rs, String columnName) throws SQLException {
        return rs.getString(columnName);
    }

    /**
     * 将从结果集根据列索引获取到的数据的jdbcType转换成javaType
     */
    @Override
    public String getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        return rs.getString(columnIndex);
    }

    /**
     *  存储过程
     */
    @Override
    public String getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        return cs.getString(columnIndex);
    }
}

<!--类型处理器-->
<typeHandlers>
    <typeHandler handler="org.pearl.mybatis.demo.handler.ExampleTypeHandler"/>
</typeHandlers>    

<typeHandlers>
  <package name="org.pearl.mybatis.demo.handler"/>
</typeHandlers>

<!-- mybatis-config.xml -->
<typeHandlers>
  <typeHandler handler="org.apache.ibatis.type.EnumOrdinalTypeHandler" javaType="java.math.RoundingMode"/>
</typeHandlers>

public class ExampleObjectFactory extends DefaultObjectFactory {

    // 处理默认构造方法
    @Override
    public <T> T create(Class<T> type) {
        return super.create(type);
    }

    // 处理有参构造方法
    @Override
    public <T> T create(Class<T> type, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) {
        return super.create(type, constructorArgTypes, constructorArgs);
    }

    // 判断集合类型参数
    @Override
    public <T> boolean isCollection(Class<T> type) {
        return super.isCollection(type);
    }

    /**
     * mybatis核心配置文件中自配置<objectFactory><property></property></objectFactory>
     * 中的property标签的内容，会在加载配置文件后，设置到Properties对象中
     */
    @Override
    public void setProperties(Properties properties) {
        super.setProperties(properties);
        System.out.println(properties.getProperty("userName"));
    }
}

<!--对象工厂-->
<objectFactory type="org.pearl.mybatis.demo.handler.ExampleObjectFactory">
    <property name="userName" value="zhangsansan"/>
</objectFactory>

@Intercepts({@Signature(type = Executor.class, method = "query",args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
public class ExamplePlugin implements Interceptor {
    private Properties properties = new Properties();

    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        Object target = invocation.getTarget(); //被代理对象
        Method method = invocation.getMethod(); //代理方法
        Object[] args = invocation.getArgs(); //方法参数
        // do something ...... 方法拦截前执行代码块
        Object result = invocation.proceed();
        // do something .......方法拦截后执行代码块
        return result;
    }

    @Override
    public void setProperties(Properties properties) {
        this.properties = properties;
    }

    @Override
    public Object plugin(Object target) {
        return Plugin.wrap(target, this);
    }
}

<!--插件-->
<plugins>
    <plugin interceptor="org.pearl.mybatis.demo.plugins.ExamplePlugin"></plugin>
</plugins>

<!--多环境配置-->
<!--default默认使用的环境ID，此处表示默认使用开发环境配置-->
<environments default="development">
<!--开发环境配置-->
<!--id：指定当前环境的唯一标识-->
<environment id="development">
    <!--事务管理器的配置（比如：type="JDBC"）-->
    <transactionManager type="JDBC"/>
    <!--数据源的配置（比如：type="POOLED"）-->
    <dataSource type="POOLED">
        <!--驱动名-->
        <property name="driver" value="${db.driver:com.mysql.cj.jdbc.Driver}"/>
        <!--数据库地址-->
        <property name="url"
                  value="${db.url:jdbc:mysql://127.0.0.1:3306/angel_admin?serverTimezone=Asia/Shanghai}"/>
        <!--用户名-->
        <property name="username" value="${db.username:root}"/>
        <!--密码-->
        <property name="password" value="${db.password:123456}"/>
    </dataSource>
</environment>
<!--测试环境配置-->
<environment id="test">
    <transactionManager type="JDBC"/>
    <dataSource type="POOLED">
        <property name="driver" value="${db.driver:com.mysql.cj.jdbc.Driver}"/>
        <property name="url"
                  value="${db.url:jdbc:mysql://192.168.17.1:3306/angel_admin?serverTimezone=Asia/Shanghai}"/>
        <property name="username" value="${db.username:root}"/>
        <property name="password" value="${db.password:123456}"/>
    </dataSource>
</environment>

public class Test002 {
    public static void main(String[] args) throws IOException {
        // 开发环境
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream,"development");
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.selectOneById(1L);
        System.out.println(user);
        // 测试环境
        String resourceTest = "mybatis-config.xml";
        InputStream inputStreamTest = Resources.getResourceAsStream(resourceTest);
        SqlSessionFactory sqlSessionFactoryTest = new SqlSessionFactoryBuilder().build(inputStreamTest,"test");
        SqlSession sqlSessionTest = sqlSessionFactoryTest.openSession();
        UserMapper mapperTest = sqlSessionTest.getMapper(UserMapper.class);
        User userTest = mapperTest.selectOneById(1L);
        System.out.println(userTest);
    }
}

public interface TransactionFactory {
  default void setProperties(Properties props) { // 从 3.5.2 开始，该方法为默认方法
    // 空实现
  }
  Transaction newTransaction(Connection conn);
  Transaction newTransaction(DataSource dataSource, TransactionIsolationLevel level, boolean autoCommit);
}

public interface Transaction {
  Connection getConnection() throws SQLException;
  void commit() throws SQLException;
  void rollback() throws SQLException;
  void close() throws SQLException;
  Integer getTimeout() throws SQLException;
}

public interface DataSourceFactory {
  void setProperties(Properties props);
  DataSource getDataSource();
}

import org.apache.ibatis.datasource.unpooled.UnpooledDataSourceFactory;
import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0DataSourceFactory extends UnpooledDataSourceFactory {

  public C3P0DataSourceFactory() {
    this.dataSource = new ComboPooledDataSource();
  }
}

<!--数据库厂商标识-->
<!--DB_VENDOR: 使用MyBatis提供的VendorDatabaseIdProvider解析数据库厂商标识。也可以实现DatabaseIdProvider接口来自定义-->
<databaseIdProvider type="DB_VENDOR">
    <!--添加两个数据库厂商别名-->
    <!--name：数据库厂商标识-->
    <!--value：为标识起一个别名，方便SQL语句使用databaseId属性引用-->
    <property name="Oracle" value="oracle"/>
    <property name="MySQL" value="mysql"/>
</databaseIdProvider>

<mapper namespace="org.pearl.mybatis.demo.dao.UserMapper">
    <select id="selectOneById" resultType="org.pearl.mybatis.demo.pojo.entity.User" databaseId="mysql">
    select * from base_user where user_id = #{id}
  </select>
</mapper>

public class Test001 {
    public static void main(String[] args) throws IOException {
        // 根据xml配置文件（全局配置文件）创建一个SqlSessionFactory对象
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        String databaseId = sqlSessionFactory.getConfiguration().getDatabaseId();
        System.out.println(databaseId+"数据库");
        }
}

<!-- 使用相对于类路径的资源引用 -->
<mappers>
  <mapper resource="org/mybatis/builder/AuthorMapper.xml"/>
  <mapper resource="org/mybatis/builder/BlogMapper.xml"/>
  <mapper resource="org/mybatis/builder/PostMapper.xml"/>
</mappers>

<!-- 使用完全限定资源定位符（URL） -->
<mappers>
  <mapper url="file:///var/mappers/AuthorMapper.xml"/>
  <mapper url="file:///var/mappers/BlogMapper.xml"/>
  <mapper url="file:///var/mappers/PostMapper.xml"/>
</mappers>

<!-- 使用映射器接口实现类的完全限定类名 -->
<mappers>
  <mapper class="org.mybatis.builder.AuthorMapper"/>
  <mapper class="org.mybatis.builder.BlogMapper"/>
  <mapper class="org.mybatis.builder.PostMapper"/>
</mappers>

<!-- 将包内的映射器接口实现全部注册为映射器 -->
<mappers>
  <package name="org.mybatis.builder"/>
</mappers>