标签：.com user tis print blog except 文件 final mybatis
1.Mybatis动态sql是基于OGNL的表达式，可以使我们方便的在sql语句中实现某些逻辑。
2.使用if+where实现多条件查询
1〉dao层方法
//if动态sql查询 public List<User> findByIf(User user);
2〉xml配置文件的sql语句
<!-- if动态sql查询 -->
<select id="findByIf" resultType="User">
SELECT * FROM user
<where>
<if test="userName != null">
and userName like concat(‘%‘,#{userName},‘%‘)
</if>
<if test="userPassword != null">
and userPassword=#{userPassword}
</if>
</where>
</select>
3〉测试方法
//if动态sql查询 @Test public void findByIf(){ SqlSession sqlSession = null; User user = new User(); user.setUserName("测"); //]user.setUserPassword(""); try { sqlSession = MyBatisUtil.createSqlSession(); List<User> list = sqlSession.getMapper(IUserDao.class).findByIf(user); sqlSession.commit(); for (User user1 : list) { System.out.println("user-------->"+user1.getUserCode()+"\t" +user1.getUserName()); } } catch (Exception e) { e.printStackTrace(); }finally { MyBatisUtil.closeSqlSession(sqlSession); } }
3.choose，相当于java中的switch，通常与otherwise搭配
1〉dao层方法
//智能标签choose查询 public List<User> findByChoose(User user);
2〉xml配置文件中的sql语句
<!--choose动态sql查询-->
<select id="findByChoose" resultType="User">
SELECT * FROM user
<where>
<choose>
<when test="userName!=null">
and userName like concat(‘%‘,#{userName},‘%‘)
</when>
<when test="userPassword !=null">
and userPassword=#{userPassword}
</when>
<otherwise></otherwise>
</choose>
</where>
</select>
3〉测试方法
//choose动态sql查询 @Test public void findByChoose(){ SqlSession sqlSession = null; User user = new User(); user.setUserName("测"); //]user.setUserPassword(""); try { sqlSession = MyBatisUtil.createSqlSession(); List<User> list = sqlSession.getMapper(IUserDao.class).findByChoose(user); sqlSession.commit(); for (User user1 : list) { System.out.println("user-------->"+user1.getUserCode()+"\t" +user1.getUserName()); } } catch (Exception e) { e.printStackTrace(); }finally { MyBatisUtil.closeSqlSession(sqlSession); } }
4. （1）foreach：迭代一个集合，通常用于in条件------------->传入数组 array
1〉dao层方法
//智能标签foreach查询 String [] array public List<User> findByForeach(String [] depIds);
2〉xml配置文件的sql语句
<!--foreach动态sql查询 String [] array-->
<select id="findByForeach" resultType="User">
SELECT * FROM user WHERE depId in
<foreach collection="array" open="(" close=")" separator="," item="depIds">
#{depIds}
</foreach>
</select>
3〉测试方法
//foreach动态sql查询 array @Test public void findByForeach(){ SqlSession sqlSession = null; String [] depIds = {"1","2"}; try { sqlSession = MyBatisUtil.createSqlSession(); List<User> list = sqlSession.getMapper(IUserDao.class).findByForeach(depIds); sqlSession.commit(); for (User user1 : list) { System.out.println("user-------->"+user1.getUserCode()+"\t" +user1.getUserName()); } } catch (Exception e) { e.printStackTrace(); }finally { MyBatisUtil.closeSqlSession(sqlSession); } }
（2）foreach传入集合----------->list
1〉dao方法
//智能标签foreach查询 List<User> list public List<User> findByForeachList(List<Integer> list);
2〉xml文件的配置
<!--foreach动态sql查询 Liat<User> list-->
<select id="findByForeachList" resultType="User">
SELECT * FROM user WHERE depId in
<foreach collection="list" open="(" close=")" separator="," item="depIds">
#{depIds}
</foreach>
</select>
3〉测试方法
//foreach动态sql查询 list @Test public void findByForeachList(){ SqlSession sqlSession = null; List<Integer> list = new ArrayList<Integer>(); list.add(1); try { sqlSession = MyBatisUtil.createSqlSession(); List<User> list1 = sqlSession.getMapper(IUserDao.class).findByForeachList(list); sqlSession.commit(); for (User user3 : list1) { System.out.println("user-------->"+user3.getUserCode()+"\t" +user3.getUserName()); } } catch (Exception e) { e.printStackTrace(); }finally { MyBatisUtil.closeSqlSession(sqlSession); } }
标签：.com user tis print blog except 文件 final mybatis
原文地址：http://www.cnblogs.com/cn-930621/p/7577170.html
