mybatis中的延迟加载类型及设定详解

<settings>
    <!-- 延迟加载总开关 -->
    <setting name="lazyLoadingEnabled" value="false"/>
</settings>

<settings>
    <!-- 延迟加载总开关 -->
    <setting name="lazyLoadingEnabled" value="true"/>
    <!-- 侵入式延迟加载开关 -->
    <setting name="aggressiveLazyLoading" value="true"/>
</settings>

<settings>
    <!-- 延迟加载总开关 -->
    <setting name="lazyLoadingEnabled" value="true"/>
    <!-- 侵入式延迟加载开关 -->
    <setting name="aggressiveLazyLoading" value="false"/>
</settings>

public class User implements Serializable{
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;
    private List<BankCard> cardList;

    get和set方法省略.....      
}


public class BankCard implements Serializable{
    private Integer id;
    private Integer uid;
    private String cardNo;

    get和set方法省略.....      
}

/**
     * 查询所有的用户
     *
     * @return
     */
    List<User> findAll();

<resultMap id="userAccountMap" type="com.example.domain.User">
    <id property="id" column="id"/>
    <result property="username" column="username"/>
    <result property="birthday" column="birthday"/>
    <result property="sex" column="sex"/>
    <result property="address" column="address"/>
    <collection property="bankCardList" ofType="com.example.domain.BankCard" column="id"
                select="com.example.dao.BankCardDao.findAllByUid"/>
</resultMap>
<select id="findAll" resultMap="userAccountMap">
    SELECT * FROM USER;
</select>

 /**
     * 根据用户ID查询账户信息
     * @return
     */
    List<BankCard> findAllByUid(Integer uid);

 
<select id="findAllByUid" resultType="com.example.domain.BankCard">
        SELECT * FROM bank_card WHERE uid = #{uid};
 </select>

configuration>
    <settings>
        <!--开启全局的懒加载-->
        <setting name="lazyLoadingEnabled" value="true"/>
        <!--关闭立即加载，其实不用配置，默认为false-->
        <setting name="aggressiveLazyLoading" value="false"/>
        <!--开启Mybatis的sql执行相关信息打印-->
        <setting name="logImpl" value="STDOUT_LOGGING" />
    </settings>


    <typeAliases>
        <typeAlias type="com.example.domain.Account" alias="account"/>
        <typeAlias type="com.example.domain.User" alias="user"/>
        <package name="com.example.domain"/>
    </typeAliases>


    <environments default="test">
        <environment id="test">
            <!--配置事务-->
            <transactionManager type="jdbc"></transactionManager>
            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test1"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <!--配置映射文件的路径-->
    <mappers>
        <mapper resource="com/example/dao/UserDao.xml"/>
        <mapper resource="com/example/dao/AccountDao.xml"/>
    </mappers>
</configuration>