Mybatis的动态sql语句if和choose

jdbc.properties：

url=jdbc\:oracle\:thin\:@localhost\:1521\:orcldriverClass=oracle.jdbc.OracleDriveraccount=scottpassword=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><!-- choosewhe    相当于   ifotherwish   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 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