mybatis简单实例

MyBatis简介

MyBatis 是一个可以自定义SQL、存储过程和高级映射的持久层框架。MyBatis 摒除了大部分的JDBC代码、手工设置参数和结果集重获。MyBatis 只使用简单的XML 和注解来配置和映射基本数据类型、Map 接口和POJO 到数据库记录。相对Hibernate和Apache OJB等“一站式”ORM解决方案而言，Mybatis 是一种“半自动化”的ORM实现。

需要使用的Jar包：mybatis-3.0.2.jar（mybatis核心包）。mybatis-spring-1.0.0.jar(与Spring结合包)。
下载地址：
http://ibatis.apache.org/tools/ibator
http://code.google.com/p/mybatis/

mybatis主配置

<?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>

<!-- 全局参数 -->
<settings>
<!-- 使全局的映射器启用或禁用缓存。 -->
<setting name="cacheEnabled" value="true"/>

<!-- 全局启用或禁用延迟加载。当禁用时，所有关联对象都会即时加载。 -->
<setting name="lazyLoadingEnabled" value="true"/>

<!-- 当启用时，有延迟加载属性的对象在被调用时将会完全加载任意属性。否则，每种属性将会按需要加载。 -->
<setting name="aggressiveLazyLoading" value="true"/>

<!-- 是否允许单条sql 返回多个数据集  (取决于驱动的兼容性) default:true -->
<setting name="multipleResultSetsEnabled" value="true"/>

<!-- 是否可以使用列的别名 (取决于驱动的兼容性) default:true -->
<setting name="useColumnLabel" value="true"/>

<!-- 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。  default:false  -->
<setting name="useGeneratedKeys" value="false"/>

<!-- 指定 MyBatis 如何自动映射 数据基表的列 NONE：不隐射　PARTIAL:部分  FULL:全部  -->
<setting name="autoMappingBehavior" value="PARTIAL"/>

<!-- 这是默认的执行类型  （SIMPLE: 简单； 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）  -->
<setting name="defaultExecutorType" value="SIMPLE"/>

<!-- 使用驼峰命名法转换字段。 -->
<setting name="mapUnderscoreToCamelCase" value="true"/>

<!-- 设置本地缓存范围 session:就会有数据的共享  statement:语句范围 (这样就不会有数据的共享 ) defalut:session -->
<setting name="localCacheScope" value="SESSION"/>

<!-- 设置但JDBC类型为空时,某些驱动程序 要指定值,default:OTHER，插入空值时不需要指定类型 -->
<setting name="jdbcTypeForNull" value="NULL"/>

</settings>

<!-- 类型别名 -->
<typeAliases>
<typeAlias alias="Page" type="com.eryansky.common.orm.Page" /><!--分页  -->
</typeAliases>

<!-- 插件配置 -->
<plugins>
<plugin interceptor="com.eryansky.common.orm.mybatis.interceptor.PaginationInterceptor" />
</plugins>

</configuration>

spring-mybatis配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"
default-lazy-init="true">

<description>Spring Mybatis Configuration</description>

<!-- 加载配置属性文件 -->
<context:property-placeholder ignore-unresolvable="true" location="classpath*:/appconfig.properties" />

<!-- MyBatis begin -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="defaultDataSource"/>
<property name="typeAliasesPackage" value="com.jfit.modules.sys.mapper,com.jfit.modules.cms.mapper,com.jfit.modules.notice.mapper,
com.jfit.modules.mobile.mapper,com.jfit.modules.form.mapper"/>
<property name="typeAliasesSuperType" value="com.eryansky.common.persistence.AbstractBaseEntity"/>
<property name="mapperLocations" value="classpath:/mappings/**/*.xml"/>
<property name="configLocation" value="classpath:/mybatis-config.xml"></property>
</bean>
<!-- 扫描basePackage下所有以@MyBatisRepository注解的接口-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
<property name="basePackage" value="com.jfit.modules.sys.dao,com.jfit.modules.cms.dao,com.jfit.modules.notice.dao,
com.jfit.modules.mobile.dao,com.jfit.modules.form.dao"/>
<property name="annotationClass" value="com.eryansky.common.orm.mybatis.MyBatisDao"/>
</bean>
<!-- MyBatis end -->

<bean class="com.eryansky.common.persistence.MapperLoader"></bean>

</beans>

实体Bean

public class TableModel extends DataEntity<TableModel> {
/**
* 分类 数据字典 TABLE_MODEl_CATEGORY
*/
private String category;
/**
* 名称
*/
private String name;
/**
* 表名称
*/
private String code;
/**
* 主键字段（@Transient）
*/
private String primaryCode;
/**
* 类型 {@link TableModelType}
*/
private String type = TableModelType.Single.getValue();

/**
* 关联类型 {@link com.jfit.modules.form._enum.TableJoinType}
*/
private String joinType;
/**
* 父表模型ID
*/
private String parentTableModelId;
/**
* 备注
*/
private String remark;

/**
* 版本号
*/
private Integer versionNo;
/**
* 是否同步数据库
*/
private Integer isSync;

private List<TableModelColumn>  columnList;

public TableModel() {}

public TableModel(String id) {
super(id);
}

public List<TableModelColumn> getColumnList() {
return columnList;
}

public void setColumnList(List<TableModelColumn> columnList) {
this.columnList = columnList;
}

public Integer getIsSync() {
return isSync;
}

public void setIsSync(Integer isSync) {
this.isSync = isSync;
}

public String getCategory() {
return category;
}

public void setCategory(String category) {
this.category = category;
}

public void setName(String name) {
this.name = name;
}

public String getName() {
return this.name;
}

public void setCode(String code) {
this.code = code;
}

public String getCode() {
return this.code;
}

public void setType(String type) {
this.type = type;
}

public String getType() {
return this.type;
}

public String getTypeView() {
TableModelType s = TableModelType.getTableModelTypeByValue(type);
String str = "";
if (s != null) {
str = s.getDescription();
}
return str;
}

public String getJoinType() {
return joinType;
}

public void setJoinType(String joinType) {
this.joinType = joinType;
}

public void setRemark(String remark) {
this.remark = remark;
}

public String getRemark() {
return this.remark;
}

public Integer getVersionNo() {
return versionNo;
}

public void setVersionNo(Integer versionNo) {
this.versionNo = versionNo;
}

public String  getParentTableModelId() {
return parentTableModelId;
}

public void setParentTableModelId(String parentTableModelId) {
this.parentTableModelId = parentTableModelId;
}

public String getPrimaryCode() {
return primaryCode;
}

public void setPrimaryCode(String primaryCode) {
this.primaryCode = primaryCode;
}
}

有mybatis注解的DAO层

@MyBatisDao
public interface TableModelDao extends CrudDao<TableModel> {
/**
* 删除所有 清空
*
* @return
*/
public int removeAll();

/**
* 判断是否存在
*
* @return
*/
public TableModel findUnique(String code);

/**
* 保存或更新
*
* @return
*/
public int saveOrUpdate(List<TableModelColumn> mColumnList);

/**
*
* 根据父ID得到 Model. <br>
* 默认按 id asc排序.
*
* @param parentId 父节点ID(当该参数为null的时候查询顶级资源列表)
* @return
*/
@SuppressWarnings("unchecked")
public List<TableModel> getByParentId(String parentId);

/**
* 删除表
*/
public void dropTable(String code);

/**
* 创建表
*/
public void createMysqlTable(Map<String, Object> params);

/**
* 更新表
*/
public void alterMysqlTable(Map<String, Object> params);

/**
* 设置同步状态
*/
public void syncStatus(String id);
}

SQL映射语句文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.jfit.modules.form.dao.TableModelDao">
/*  使用sql别名转换字段和属性名 */
<sql id="formTableModelColumns">
a.id AS "id",
a.create_user AS "createUser",
a.create_time AS "createTime",
a.status AS "status",
a.update_user AS "updateUser",
a.update_time AS "updateTime",
a.version AS "version",
a.name AS "name",
a.code AS "code",
a.type AS "type",
a.join_type AS "joinType",
a.parent_table_model_id AS "parentTableModelId",
a.remark AS "remark",
a.category AS "category",
a.version_no AS "versionNo",
a.is_sync AS "isSync"
</sql>
/* 或者用resultMap字段属性名转换
<resultMap type="TableModel" id="tableModelMap">
<id property="id" column="id"/>
<result property="createUser" column="create_user"/>
<result property="createTime" column="create_time"/>
//....省略
<result property="isSync" column="is_sync"/>
</resultMap>
在<select>标签加上resultMap="tableModelMap"也能进行字段名和属性名 转换
*/

<select id="get" resultType="TableModel">
SELECT
<include refid="formTableModelColumns"/>
FROM t_form_table_model a
WHERE a.id = #{id}
</select>

<select id="findList" resultType="TableModel">
SELECT
<include refid="formTableModelColumns"/>
FROM t_form_table_model a
<where>
a.status = #{STATUS_NORMAL}
</where>
<choose>
<when test="entityPage !=null and entityPage.orderBy != null and entityPage.orderBy != ''">
ORDER BY ${entityPage.orderBy}
</when>
<otherwise>
ORDER BY a.update_time DESC
</otherwise>
</choose>
</select>

<select id="findByParentId" resultType="TableModel">
SELECT
<include refid="formTableModelColumns"/>
FROM t_form_table_model a
<where>
a.status = #{STATUS_NORMAL}
<choose>
<when test="parentId !=null and parentId!= ''">
AND
</when>
<otherwise>
ORDER BY a.update_time DESC
</otherwise>
</choose>
</where>
<choose>
<when test="entityPage !=null and entityPage.orderBy != null and entityPage.orderBy != ''">
ORDER BY ${entityPage.orderBy}
</when>
<otherwise>
ORDER BY a.update_time DESC
</otherwise>
</choose>
</select>

<select id="findUnique" resultType="TableModel">
SELECT
<include refid="formTableModelColumns"/>
FROM t_form_table_model a
WHERE a.code = #{code}
</select>

<insert id="insert">
INSERT INTO t_form_table_model(
id,
status,
version,
create_user,
create_time,
update_user,
update_time,
name,
code,
type,
join_type,
parent_table_model_id,
remark,
category,
version_no,
is_sync
) VALUES (
#{id},
#{status},
#{version},
#{createUser},
#{createTime},
#{updateUser},
#{updateTime},
#{name},
#{code},
#{type},
#{joinType},
#{parentTableModelId},
#{remark},
#{category},
#{versionNo},
#{isSync}
)
</insert>

<update id="update">
UPDATE t_form_table_model SET
status = #{status},
version = version +1,
update_user = #{updateUser},
update_time = #{updateTime},
name = #{name},
code = #{code},
type = #{type},
join_type = #{joinType},
parent_table_model_id = #{parentTableModelId},
remark = #{remark},
category=#{category},
version_no=#{versionNo},
is_sync=#{isSync}
WHERE id = #{id}
</update>

<delete id="delete">
update  t_form_table_model
set status='1'
WHERE id = #{id}
</delete>

<update id="createMysqlTable">
create table ${table}
<foreach  collection="list" index="index" item="column" open="(" separator="," close=")">
${column.code}  ${column.dataType}(${column.columnSize}<if test="column.scale != null and column.dataType=='DOUBLE'">,${column.scale}</if>)
<if test="column.defaultValue!='' and (column.dataType == 'int' or column.dataType == 'double')">DEFAULT ${column.defaultValue} </if>
<if test="column.defaultValue!='' and column.dataType == 'varchar'">DEFAULT '${column.defaultValue}' </if>
<if test="column.isNull == 0">not null</if>
<if test="column.comment!= null and column.comment !=''">comment '${column.comment}'</if>
<if test="column.isPrimary == 1">,primary key (${column.code})</if>
<if test="column.isUnique == 1">,unique key ${column.code}(${column.code})</if>
</foreach>
comment '${comment}'
</update>

<update id="alterMysqlTable">
${sql}
</update>

<update id="syncStatus">
update  t_form_table_model
set is_sync='1'
WHERE id = #{id}
</update>
</mapper>

下一篇讲解mybatis配置文件标签语法及其参数传递