Mybatis的动态sql语句if和choose

jdbc.properties：

url=jdbc\:oracle\:thin\:@localhost\:1521\:orcl
driverClass=oracle.jdbc.OracleDriver
account=scott
password=tiger

mybatis.xml：

<?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="cn/et/mybatis/lesson01/jdbc.properties">

</properties>

<!--
配置连接数据库的环境   development开发环境
-->
<environments default="development">
<environment id="development">
<!-- 事务交给JDBC来管理   也就是通过 Connection的 commit和rollback管事事务 -->
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driverClass}"/>
<property name="url" value="${url}"/>
<property name="username" value="${account}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="cn/et/mybaits/lesson02/dynsql/dy_mapper.xml" />
</mappers>
</configuration>

dy_mapper.xml：

<?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">

<!--
接口映射
namespace必需跟接口的全名一致
-->
<mapper namespace="cn.et.mybaits.lesson02.dynsql.DyMapper">

<!--
动态的sql语句
-->
<select id="selectEmp" resultType="map" parameterType="map">
select * from emp where 1=1
<if test="ename!=null">
and ename=#{ename}
</if>
</select>

<!--
choose
whe 相当于 if
otherwish 相当于 else
-->

<select id="selectEmpBySal" resultType="map" parameterType="map">
select * from emp where 1=1
<choose>
<when test="sal==null">
<!--
< < 小于
> > 大于
<![CDATA[>]]>
不解析代码块中的代码
-->
and sal <![CDATA[>]]>= 0
</when>
<otherwise>
and sal=#{sal}
</otherwise>
</choose>
</select>

</mapper>

DyMapper接口：

package cn.et.mybaits.lesson02.dynsql;

import java.util.List;
import java.util.Map;

public interface DyMapper {

public List<Map> selectEmp(Map map);

public List<Map> selectEmpBySal(Map map);
}

TestMybatis：

package cn.et.mybaits.lesson02.dynsql;

import java.io.InputStream;
import java.util.HashMap;
import
4000
java.util.List;
import java.util.Map;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class TestMybatis {

public static SqlSession getSession(){
String resource = "/cn/et/mybaits/lesson02/mybatis.xml";
InputStream inputStream = TestMybatis.class.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//打开会话
SqlSession session = sqlSessionFactory.openSession();
return session;
}

/*public static void main(String[] args) {
SqlSession session = getSession();
DyMapper dy = session.getMapper(DyMapper.class);
Map map = new HashMap();
map.put("ename", "李黑");
List list = dy.selectEmp(map);
System.out.println(list.size());

}*/

public static void main(String[] args) {
SqlSession session = getSession();
DyMapper dy = session.getMapper(DyMapper.class);
Map map = new HashMap();
map.put("sal", 5000);
List list = dy.selectEmpBySal(map);
System.out.println(list.size());

}
}

mybatis注解的动态sql语句映射：

package cn.et.mybaits.lesson02.homework;

import java.util.List;
import java.util.Map;

import org.apache.ibatis.annotations.Select;

public interface DyAnnoMapper {

@Select(value="<script>select * from emp where 1=1 <if test='sal!=null'> and sal>=#{sal}</if></script>")
public List<Map<String, Object>> query(Map map);
}

其他调用方法一法