Mapper代理的输入映射和输出映射

输入映射类型：

简单类型

1映射文件

<!-- 根据用户ID查询用户信息 --><select id="findUserById" parameterType="int" resultType="cn.itcast.po.User">select * from user where id = #{id}</select>

2Mapper接口

//根据用户ID查询用户信息 public User findUserById(int id)  throws Exception;

3测试

public class UserMapperTest {private SqlSessionFactory sqlSessionFactory;@Beforepublic void setUp() throws Exception {//读取配置文件String resource ="SqlMapConfig.xml";InputStream inputStream =  Resources.getResourceAsStream(resource);//创建SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);}@Testpublic void testFindUserById() throws Exception {//创建UserMapper对象SqlSession sqlSession =  sqlSessionFactory.openSession();//由mybatis通过Sqlsession创建代理对象UserMapper userMapper = sqlSession.getMapper(UserMapper.class);User user = userMapper.findUserById(1) ;System.out.println(user);sqlSession.close();}}

pojo类型

1映射文件

<!-- 添加用户 --><insert id="insertUser" parameterType="cn.itcast.po.User">insert into User(username, birthday, sex, address) values(#{username}, #{birthday},#{sex},#{address})</insert>

2Mapper接口

//添加用户 public void insertUser(User user);

3测试

@Testpublic void testInsertUser() {//创建UserMapper对象SqlSession sqlSession = sqlSessionFactory.openSession(true) ;UserMapper userMapper = sqlSession.getMapper(UserMapper.class) ;User user = new User() ;user.setUsername("znzn");user.setAddress("hubei");userMapper.insertUser(user);sqlSession.close();}

包装类型

1定义包装pojo类型类

package cn.itcast.po;


import java.util.HashMap;
import java.util.Map;


public class UserCustom {
private User user ;
Map<String, Object> map = new HashMap<String, Object>() ;


public User getUser() {
return user;
}


public void setUser(User user) {
this.user = user;
}


public Map<String, Object> getMap() {
return map;
}


public void setMap(Map<String, Object> map) {
this.map = map;
}




}

2映射文件

<select id="findUserList" parameterType="cn.itcast.po.UserCustom" resultType="cn.itcast.po.User">select * from user whereusername like '%${user.username}%'and sex = #{user.sex}</select>

3Mapper接口

public List<User> findUserList(UserCustom user) ;

4测试

@Testpublic void testFindUserList() {//创建UserMapper对象SqlSession sqlSession = sqlSessionFactory.openSession(true) ;UserMapper userMapper = sqlSession.getMapper(UserMapper.class) ;UserCustom userCustom = new UserCustom();User user = new User() ;user.setSex("1");user.setUsername("小明");userCustom.setUser(user);List<User> list = userMapper.findUserList(userCustom);int count = userMapper.findUserCount(userCustom);System.out.println(list);System.out.println(count);sqlSession.close();}

map或list类型

1映射文件

<select id="findUserByIdList" parameterType="java.util.List" resultType="user">select * from user<where><if test="list != null and list.size() > 0"><foreach collection="list" item="id" open="And id IN(" close=")" separator=",">#{id}</foreach></if></where></select>

2UserMapper接口

public List<User> findUserByIdList(List<Integer> idList);

3测试

@Testpublic void testFindUserByIdList(){SqlSession sqlSession = sqlSessionFactory.openSession();UserMapper userMapper = sqlSession.getMapper(UserMapper.class);List<Integer> idList = new ArrayList<Integer>();idList.add(1);idList.add(10);idList.add(16);List<User> list = userMapper.findUserByIdList(idList);System.out.println(list);}

输出类型

分两种 resultType 和 resultMap

resultType简单类型 pojo类型

简单类型

1映射文件

<select id="findUserCount" parameterType="cn.itcast.po.UserCustom" resultType="int">select count(*) from user whereusername like '%${user.username}%'and sex = #{user.sex}</select>

pojo类型

<!-- 根据用户ID查询用户信息 --><select id="findUserById" parameterType="int" resultType="cn.itcast.po.User">select * from user where id = #{id}</select>

resultMap     pojo类型

1映射文件

<!-- resultMap入门  id标签 专门为查询结果中唯一列映射 result映射查询结果中的普通列 --><resultMap type="cn.itcast.po.User" id="UserRstMap"><id column="id_" property="id" /><result column="username_" property="username"/><result column="sex_" property="sex" /></resultMap><select id="findUserRstMap" parameterType="int" resultMap="UserRstMap">select id id_,  username username_, sex sex_ from user where id = #{id}</select>

2Mapper接口

public User findUserRstMap(int id) ;

3测试

@Testpublic void testFindUserRstMap() {//创建UserMapper对象SqlSession sqlSession = sqlSessionFactory.openSession(true) ;UserMapper userMapper = sqlSession.getMapper(UserMapper.class) ;User user = userMapper.findUserRstMap(1);System.out.println(user);sqlSession.close();}