mabits

一、传入参数的传递

parameterType指定参数类型

基本类型参数（int、string.......）

pojo类型：user对象

map类型

包装类型

1、map类型的传递

需求：查询用户性别为男，姓张的用户

1. namespace="com.itcast.dao.UserMapper" >
3. id="findUserWithMap" parameterType="map" resultType="user" >
4. select * from user where sex=#{sex} and username like "%"#{username}"%"

1. @Test
2. public void fun1() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. Map<String, Object> map = new HashMap<>();
8. map.put("sex", "男");
9. map.put("username", "张");
10. List<User> list = userMapper.findUserWithMap(map);
11. System.out.println(list);
12. }

2、包装类型的传递

需求：查询用户性别为男，姓张的用户

2. id="findUserWithQueryVo" parameterType="queryvo" resultType="user" >
3. select * from user where sex=#{user.sex} and username like "%"#{user.username}"%"

1. @Test
2. public void fun2() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. User user = new User();
8. user.setSex("男");
9. user.setUsername("张");
10. QueryVo queryVo = new QueryVo();
11. queryVo.setUser(user);
12. List<User> list = userMapper.findUserWithQueryVo(queryVo);
13. System.out.println(list);
14. }

 

二、返回参数的类型

基本类型

pojo类型

返回集合类型

 

1、返回基本类型

需求：查询用户性别为男，姓张的用户总计数

2. id="findUserWithQueryVoCount" parameterType="queryvo" resultType="int" >
3. select count(2) from user where sex=#{user.sex} and username like "%"#{user.username}"%"

1. @Test
2. public void fun3() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. User user = new User();
8. user.setSex("男");
9. user.setUsername("张");
10. QueryVo queryVo = new QueryVo();
11. queryVo.setUser(user);
12. int count = userMapper.findUserWithQueryVoCount(queryVo);
13. System.out.println(count);
14. }

2、resultType特性

特性：查询数据库列名必须和映射的javabean属性名称一一对应，且名称相同，否则不能映射成功

验证：

2. id="findUserWithResultType" resultType="user" >
3. select id _id,username _username,birthday _birthday,sex _sex,address _address from user

1. @Test
2. public void fun4() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. List<User> list= userMapper.findUserWithResultType();
8. System.out.println(list);
9. }

 

返回结果错误：[null, null, null, null, null, null, null, null, null]

 

解决映射不成功的方案：

    *    定义别名

    *    resultMap

 

3、resultMap映射特点

解决resultType 数据库列名与javabean属性名不相同不能映射的问题

需要先定义一个resultMap的映射关系

                    主键映射 :使用id

        column:查询数据库列名

        property:javabean属性名

2. type="user" id="userMap">
4. column="_id" property="id" />
5.  
7. column="_username" property="username" />
8. column="_birthday" property="birthday" />
9. column="_sex" property="sex" />
10. column="_address" property="address" />
12.  
14. id="findUserWithResultMap" resultMap="userMap" >
15. select id _id,username _username,birthday _birthday,sex _sex,address _address from user

java代码和上面一样

 

 

三、多表关联的查询：

1、多的一方    一对一查询

   可以用resultType也可以用resultMap查询

①  用resultType来映射

需求：通过订单查询用户和订单所有数据，一个订单只对应一个用户，所以是一对一查询

新定义一个订单实体类，再用一个OrdersCustom类继承Orders类中所有属性，再添加User类中的所有属性，注意把User类中的主键名字改成uid，因为不能和Orders的主键id名字重复啊，查询后的结果就封装在OrdersCustom这个类的属性中

1. namespace="com.itcast.dao.OrdersMapper" >
2. id="findOrdersWithUserByResultType" resultType="ordersCustom" >
3. select o.id,o.user_id userId,o.number,o.createtime createTime,o.note,
4. u.id uid,u.username,u.birthday,u.sex,u.address
5. from user u,orders o where u.id=o.user_id

1. @Test
2. public void fun1() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. OrdersMapper ordersMapper = sqlSession.getMapper(OrdersMapper.class);
7. List<OrdersCustom> list = ordersMapper.findOrdersWithUserByResultType();
8. System.out.println(list);
9. }

 

②用resultMap来映射

                       配置一对一关系映射:association 

property:指定映射orders中那个属性

javaType:指定关系映射对象类型

1. namespace="com.itcast.dao.OrdersMapper" >
3. type="orders" id="ordersMap">
5. column="id" property="id" />
6.  
8. column="user_id" property="userId" />
9. column="number" property="number" />
10. column="createtime" property="createTime" />
11. column="note" property="note" />
12.  
14. property="user" javaType="user">
15. column="uid" property="id" />
16.  
17. column="username" property="username" />
18. column="birthday" property="birthday" />
19. column="sex" property="sex" />
20. column="address" property="address" />
23.  
24. id="findOrdersWithUserByResultMap" resultMap="ordersMap" >
25. SELECT orders.*,user.id uid,user.username,user.birthday,user.sex,user.address
26. FROM orders,user WHERE orders.user_id = user.id

1. @Test
2. public void fun2() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. OrdersMapper ordersMapper = sqlSession.getMapper(OrdersMapper.class);
7. List<Orders> list = ordersMapper.findOrdersWithUserByResultMap();
8. System.out.println(list);
9. }

 

 

2、一的一方    一对多查询

一个用户对应了多个订单，如果通过用户查询用户数据和对应的订单数据，那就是一对多查询

一对多查询只能用resultMap来映射

1. namespace="com.itcast.dao.UserMapper" >
2. type="user" id="userMap">
3. column="uid" property="id" />
4. column="username" property="username"/>
5. column="birthday" property="birthday"/>
6. column="sex" property="sex"/>
7. column="address" property="address"/>
9. property="oList" ofType="orders" >
11. column="id" property="id"/>
13. column="user_id" property="userId"/>
14. column="number" property="number"/>
15. column="createtime" property="createTime"/>
16. column="note" property="note"/>
19.  
20.  
22. id="findUserWithOrdersByMap" resultMap="userMap" >
23. select user.id uid,user.username,user.birthday,user.sex,user.address,
24. orders.id,orders.user_id userId,orders.number,orders.createtime createTime,orders.note
25. from user,orders where orders.user_id=user.id

1. @Test
2. public void fun3() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. List<User> list = userMapper.findUserWithOrdersByMap();
8. System.out.println(list);
9. }

 

 

四、动态sql查询

1、if标签和where标签连用

       where标签自动生成where语句，并且where标签可以自动去掉sql语句的第一个多余的“and”

       if标签：：当if标签传入的是pojo类型，或者包装类型，test里面就直接写传入类型里面的属性名，但是当传入的parameterType是基本数据类型，例如string，如要判断string类型的内容，则需要在test里面判断：_parameter

①不用where标签的做法：

2. id="findUserWithQueryVo" parameterType="queryvo" resultType="user" >
3. select * from user where 1=1
4. test="user.sex!=null and user.sex!=''">
5. and sex=#{user.sex}
7. test="user.username!=null and user.username!=''">
8. and username like "%"#{user.username}"%"

1. @Test
2. public void fun2() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. User user = new User();
8. user.setSex(null);
9. user.setUsername("张");
10. QueryVo queryVo = new QueryVo();
11. queryVo.setUser(user);
12. List<User> list = userMapper.findUserWithQueryVo(queryVo);
13. System.out.println(list);
14. }

 

②用where标签的做法：

2. id="findUserWithQueryVo" parameterType="queryvo" resultType="user" >
3. select * from user
6. test="user.sex!=null and user.sex!=''">
7. and sex=#{user.sex}
9. test="user.username!=null and user.username!=''">
10. and username like "%"#{user.username}"%"

java程序和上面一样

 

 

2、动态更新语句：

标签类似于where标签

 

 

 

 

3、sql片段

       把相同的sql片段抽取出去

标签定义片段；；来引入sql片段

id和refid相对应

1. namespace="com.itcast.dao.UserMapper" >
2.  
4. id="where_if_vo">
6. test="user.sex!=null and user.sex!=''">
7. and sex=#{user.sex}
9. test="user.username!=null and user.username!=''">
10. and username like "%"#{user.username}"%"
14.  
15.  
17. id="findUserWithQueryVo" parameterType="queryvo" resultType="user" >
18. select * from user
20. refid="where_if_vo">
22.  
24. id="findUserWithQueryVoCount" parameterType="queryvo" resultType="int" >
25. select count(2) from user
26. refid="where_if_vo">

 

4、foreach动态遍历集合参数

①第一种方法：

    select * from user where （id=22 or id=23 or id=33）

   

2. id="findUserWithOr" parameterType="queryvo" resultType="user" >
3. select * from user
5. collection="ids" item="id" open="(" separator="or" close=")" >
6. id=#{id}

1. @Test
2. public void fun4() throws IOException{
3. InputStream inputStream = Resources.getResourceAsStream("sqlMapConfig.xml");
4. SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
5. SqlSession sqlSession = sqlSessionFactory.openSession();
6. UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
7. QueryVo queryVo = new QueryVo();
8. List<Integer> ids = new ArrayList<>();
9. ids.add(22);
10. ids.add(24);
11. ids.add(26);
12. queryVo.setIds(ids);
13. List<User> list = userMapper.findUserWithOr(queryVo);
14. System.out.println(list);
15. }

 

②另一种方法：

select *  from user where id in （22,23,33）

2. id="findUserWithIn" parameterType="queryvo" resultType="user" >
3. select * from user
5. collection="ids" item="id" open="id IN(" separator="," close=")" >
6. #{id}

java代码只要改个方法名即可

 

arraylist、list=======》list

数组====》array

 

 

 

 

五、mybatis和spring整合

spring配置文件：

1. xml version="1.0" encoding="UTF-8"?>
2. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3. xmlns:aop="http://www.springframework.org/schema/aop"
4. xmlns="http://www.springframework.org/schema/beans"
5. xmlns:context="http://www.springframework.org/schema/context"
6. xmlns:tx="http://www.springframework.org/schema/tx"
7. xsi:schemaLocation="http://www.springframework.org/schema/aop
8. http://www.springframework.org/schema/aop/spring-aop-4.2.xsd
9. http://www.springframework.org/schema/beans
10. http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
11. http://www.springframework.org/schema/context
12. http://www.springframework.org/schema/context/spring-context-4.2.xsd
13. http://www.springframework.org/schema/tx
14. http://www.springframework.org/schema/tx/spring-tx-4.2.xsd ">
15.  
16.  
17. location="classpath:jdbc.properties" />
20. id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" >
21. name="driverClassName" value="${jdbc.driver}">
22. name="url" value="${jdbc.url}">
23. name="username" value="${jdbc.username}">
24. name="password" value="${jdbc.password}">
26.  
28. id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean" >
29. name="dataSource" ref="dataSource" >
31. name="typeAliasesPackage" value="com.itcast.domain" >
33. name="configLocation" value="classpath:sqlMapConfig.xml" >
35.  
37. class="org.mybatis.spring.mapper.MapperScannerConfigurer" >
38. name="basePackage" value="com.itcast.dao" >

另一种扫描接口的方法：

或者直接在sqlMapConfig.xml里面配置

 

1、传统模式整合：

applicationContext.xml配置

1. xml version="1.0" encoding="UTF-8"?>
2. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3. xmlns:aop="http://www.springframework.org/schema/aop"
4. xmlns="http://www.springframework.org/schema/beans"
5. xmlns:context="http://www.springframework.org/schema/context"
6. xmlns:tx="http://www.springframework.org/schema/tx"
7. xsi:schemaLocation="http://www.springframework.org/schema/aop
8. http://www.springframework.org/schema/aop/spring-aop-4.2.xsd
9. http://www.springframework.org/schema/beans
10. http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
11. http://www.springframework.org/schema/context
12. http://www.springframework.org/schema/context/spring-context-4.2.xsd
13. http://www.springframework.org/schema/tx
14. http://www.springframework.org/schema/tx/spring-tx-4.2.xsd ">
15.  
16.  
17. location="classpath:jdbc.properties" />
20. id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" >
21. name="driverClassName" value="${jdbc.driver}">
22. name="url" value="${jdbc.url}">
23. name="username" value="${jdbc.username}">
24. name="password" value="${jdbc.password}">
26.  
28. id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean" >
29. name="dataSource" ref="dataSource" >
31. name="typeAliasesPackage" value="com.itcast.domain" >
33. name="configLocation" value="classpath:sqlMapConfig.xml" >
35.  
36.  
38. class="com.itcast.dao.impl.UserMapperImpl" >
39. name="sqlSessionFactory" ref="sqlSessionFactory" >
41.  

 

sqlMapConfig.xml配置：

4. resource="com/itcast/dao/UserMapper.xml" />

使用传统模式，有实现类

1. public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper{
2. @Override
3. public List<User> findUserWithQueryVo(QueryVo queryVo) {
4. List<User> list = this.getSqlSession().selectList("com.itcast.dao.UserMapper.findUserWithQueryVo", queryVo);
5. return list;
6. }
7. }

测试类：

1. @Test
2. public void fun2() throws IOException{
3. ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
4. UserMapperImpl mapperImpl = context.getBean(UserMapperImpl.class);
5. User user = new User();
6. user.setSex("男");
7. user.setUsername("张");
8. QueryVo queryVo = new QueryVo();
9. queryVo.setUser(user);
10. List<User> list = mapperImpl.findUserWithQueryVo(queryVo);
11. System.out.println(list);
12. }

 

2、接口代理模式整合：

applicationContext.xml加上接口扫描即可

 

测试：

UserMapper bean = context.getBean(UserMapper.class);