Mybatis支持多个条件的查询,使用if标签拼接。
下面是三个条件的查询得例子,使用的数据库是mysql,用到了模糊查询及in做条件查询。
xml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="">
<select id="selectTeacher" parameterType="map" resultType="map">
select t.tid,t.tname,t.taddr
from test_teacher t
where 1=1
<if test="tid != '' and tid != null">
and tid=#{tid}
</if>
<if test="tname != '' and tname != null">
and tname like #{tname}
</if>
<if test="addrs != '' and addrs != null">
and taddr in
<foreach item="item" index="index" collection="addrs" open="("
separator="," close=")">
#{item}
</foreach>
</if>
</select>
</mapper>
dao层:
package mybatis.dao;
import java.util.List;
public interface TestTeacherDao {
public List selectTeacher(String tid,String tname,List addrs);
}
package mybatis.dao;import java.io.InputStream;import java.util.ArrayList;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 TestTeacherDaoImpl implements TestTeacherDao { private int res=-1; private SqlSession sqlSession=null; public SqlSession getSqlSession(){ try{ String resource="mybatis-config.xml"; InputStream is=org.apache.ibatis.io.Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(is); sqlSession=sqlSessionFactory.openSession(true); }catch(Exception e){ System.out.println("出错"); e.printStackTrace(); } return sqlSession; } @Override public List selectTeacher(String tid,String tname,List addrs) { Map map=new HashMap(); map.put("tid", tid); map.put("tname", "%"+tname+"%"); map.put("addrs",addrs); sqlSession=getSqlSession(); List list=sqlSession.selectList("selectTeacher", map); return list; }}
测试:
package mybatis.test;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import mybatis.dao.TestTeacherDao;
import mybatis.dao.TestTeacherDaoImpl;
public class Test {
public static void main(String[] args) {
TestTeacherDao td=new TestTeacherDaoImpl();
List addrs=new ArrayList();
addrs.add("shandong");
addrs.add("beijing");
List list=td.selectTeacher("", "",addrs);
for(int i=0;i<list.size();i++){
Map map=(Map)(list.get(i));
System.out.println(map.get("tname"));
}
}
}