1、MyBatis介绍
MyBatis 本是apache的一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code,并且改名为MyBatis 。2013年11月迁移到Github。
iBATIS一词来源于“internet”和“abatis”的组合,是一个基于Java的持久层框架。iBATIS提供的持久层框架包括SQL Maps和Data Access Objects(DAO)
2、CLOB
SQL CLOB 是内置类型,它将字符大对象 (Character Large Object) 存储为数据库表某一行中的一个列值。默认情况下,驱动程序使用 SQL locator(CLOB) 实现 Clob 对象,这意味着 CLOB 对象包含一个指向 SQL CLOB 数据的逻辑指针而不是数据本身。Clob 对象在它被创建的事务处理期间有效。
3、MyBatis对CLOB类型数据实现增删改查
oracle表结构
create table T_USERS(
ID NUMBER not null,
NAME VARCHAR2(30),
SEX VARCHAR2(3),
BIRS DATE,
MESSAGE CLOB
)
create sequence SEQ_T_USERS_ID
minvalue 1
maxvalue 99999999
start with 1
increment by 1
cache 20;
配置mybatis配置文件UsersMapperxml
<xml version="10" encoding="UTF-8"><!DOCTYPE mapper
PUBLIC "-//mybatisorg//DTD Mapper 30//EN">
<mapper namespace="examplesmapperUsersMapper" >
<!-- Result Map-->
<resultMap type="examplesbeanUsers" id="BaseResultMap">
<result property="id" column="id" />
<result property="name" column="name" />
<result property="sex" column="sex" />
<result property="birs" column="birs" jdbcType="TIMESTAMP"/>
<result property="message" column="message" jdbcType="CLOB"
javaType = "javalangString" typeHandler ="examplesserviceOracleClobTypeHandler"/>
</resultMap>
<sql id="Tabel_Name">
t_users
</sql>
<!-- 表中所有列 -->
<sql id="Base_Column_List" >
id,name,sex,birs,message
</sql>
<!-- 查询条件 -->
<sql id="Example_Where_Clause">
where 1=1
<trim suffixOverrides=",">
<if test="id != null">
and id = #{id}
</if>
<if test="name != null and name != ''">
and name like concat(concat('%', '${name}'), '%')
</if>
<if test="sex != null and sex != ''">
and sex like concat(concat('%', '${sex}'), '%')
</if>
<if test="birs != null">
and birs = #{birs}
</if>
<if test="message != null">
and message = #{message}
</if>
</trim>
</sql>
<!-- 2查询列表 -->
<select id="queryByList" resultMap="BaseResultMap" parameterType="Object">
select
<include refid="Base_Column_List" />
from t_users
<include refid="Example_Where_Clause"/>
</select>
</mapper>
Mapper类接口
package examplesmapper;import javautilList;
public interface UsersMapper<T> {
public List<T> queryBySelective(T t);
public List<T> queryByList(T t);
}
类型转换工具类
package examplesservice;import javasqlCallableStatement;
import javasqlPreparedStatement;
import javasqlResultSet;
import javasqlSQLException;
import oraclesqlCLOB;
import orgapacheibatistypeJdbcType;
import orgapacheibatistypeTypeHandler;
public class OracleClobTypeHandler implements TypeHandler<Object> {
public Object valueOf(String param) {
return null;
}
@Override
public Object getResult(ResultSet arg0, String arg1) throws SQLException {
CLOB clob = (CLOB) arg0getClob(arg1);
return (clob == null || cloblength() == 0) null : clobgetSubString((long) 1, (int) cloblength());
}
@Override
public Object getResult(ResultSet arg0, int arg1) throws SQLException {
return null;
}
@Override
public Object getResult(CallableStatement arg0, int arg1) throws SQLException {
return null;
}
@Override
public void setParameter(PreparedStatement arg0, int arg1, Object arg2, JdbcType arg3) throws SQLException {
CLOB clob = CLOBempty_lob();
clobsetString(1, (String) arg2);
arg0setClob(arg1, clob);
}
}
Spring配置文件
<xml version="10" encoding="UTF-8"><beans xmlns="
xmlns:xsi="
xmlns:mvc="
xmlns:tx="
xsi:schemaLocation="
default-autowire="byType">
<!-- 配置数据源 -->
<bean id="dataSource" class="orgspringframeworkjdbcdatasourceDriverManagerDataSource">
<property name="driverClassName"><value>oraclejdbcdriverOracleDriver</value></property>
<property name="url"><value>jdbc:oracle:thin:@127001:1521:pms</value></property>
<property name="username"><value>pms</value></property>
<property name="password"><value>pms</value></property>
</bean>
<!-- 配完数据源 和 拥有的 sql映射文件 sqlSessionFactory 也可以访问数据库 和拥有 sql *** 作能力了 -->
<!--
<bean id="sqlSessionFactory" class="orgmybatisspringSqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation" value="classpath:mybatis-configxml"/>
</bean>
-->
<bean id="sqlSessionFactory" class="orgmybatisspringSqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="mapperLocations">
<list>
<value>classpath:examples/mybatis/oracle/UsersMapperxml</value>
</list>
</property>
</bean>
<!-- 通过设置 mapperInterface属性,使接口服务bean 和对应xml文件管理 可以使用其中的sql -->
<bean id="dao" class="orgmybatisspringmapperMapperFactoryBean">
<!-- 此处等同于 Mybatis 中 ServerDao serverDao = sqlSessiongetMapper(ServerDaoclass); 指明映射关系 -->
<property name="mapperInterface" value="examplesmapperUsersMapper" />
<property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>
</beans>
测试类
package examplesservice;import javatextParseException;
import javatextSimpleDateFormat;
import javautilList;
import orgspringframeworkcontextApplicationContext;
import orgspringframeworkcontextsupportClassPathXmlApplicationContext;
import examplesbeanUsers;
import examplesmapperUsersMapper;
public class TestUsersService {
@SuppressWarnings("unchecked")
public static void main(String[] args) throws ParseException {
ApplicationContext ac =
new ClassPathXmlApplicationContext("classpath:/examples/service/springxml");
UsersMapper<Users> dao = (UsersMapper<Users>)acgetBean("dao");
//查询
Users nullBean = new Users();
List<Users> list = daoqueryByList(nullBean);
if(list != null) {
for(Users user : list) {
Systemoutprintln(user);
}
}
}
}
/
封装Spring ApplicationConext引用, 方便工程通过API获取bean实例
@author bjb-336
/
@Component
public class SpringContextWrapper implements ApplicationContextAware{
private static ApplicationContext appContext;
/
根据beanName 获取bean实例
@param beanName
@return
/
public static Object getBean(String beanName){
Object obj = null;
if (null != appContext){
obj = appContextgetBean(beanName);
}
return obj;
}
/
根据bean名称和类型进行获取Bean的实例
@param beanName
@param clsType
@return
/
public static <T> T getBean(String beanName, Class<T> clsType){
T obj = null;
if (null != appContext){
obj = appContextgetBean(beanName, clsType);
}
return obj;
}
/
根据类型进行获取Bean的实例
@param clsType
@return
/
public static <T> T getBean(Class<T> clsType){
T obj = null;
if (null != appContext){
obj = appContextgetBean(clsType);
}
return obj;
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
SpringContextWrapperappContext = applicationContext;
}
}
在平时的工作中有时候是需要在配置文件中配置全局变量的,因为这些东西是不会变的,并且每个mapper都传参的话也显得有点繁琐,还好mybatis本身是支持全局变量的,今天工作中用到了,记录一下。
先在实例化sqlSessionFactory的时候添加上mybatis-configurationxml的配置文件
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<bean id="sqlSessionFactory" class="orgmybatisspringSqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="mapperLocations" value="classpath:mapping/xml" />
<property name="configLocation" value="classpath:mybatis-configurationxml" />
</bean>
之后在mybatis-configuration配置文件中添加全局变量
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<xml version="10" encoding="UTF-8">
<!DOCTYPE configuration
PUBLIC "-//mybatisorg//DTD Config 30//EN"
">
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