mybatis學習筆記（二）之XML方式的基本用法
阿新 • • 發佈：2018-12-15
在前一篇筆記中，我們建立了配置 mybatis-config.xml 檔案，原來 mappers標籤下的內容為：
<mappers>
<mapper resource="tk/mybatis/simple/mapper/CountryMapper.xml" />
</mappers> 為了配置簡單，我們採用配置包的形式新增mapper介面，修改為：
<mappers> <package name="tk.mybatis.simple.mapper" /> </mappers>
該種方式會去掃描tk.mybatis.simple.mapper包下的所有介面
接下來開始我們的專案，專案的目錄結構如下：
src/main/resources包的目錄結構：
接下來是程式碼部分內容，程式碼主要就是SysUser.java實體、UserMapper.Java介面、UserMapper.xml對映檔案和UserMapperTest.Java測試程式碼四部分
SysUser.Java實體的程式碼
package tk.mybatis.simple.model; public class SysUser { private Long id; private String userName; private String userPassword; private String userInfo; private byte[] headImg; private Date createTime; getter()、setter()方法 }
UserMapper.Java介面的程式碼：
package tk.mybatis.simple.mapper; import java.util.List; import org.apache.ibatis.annotations.Param; import tk.mybatis.simple.model.SysRole; import tk.mybatis.simple.model.SysUser; public interface UserMapper { /** * 根據id查詢使用者 * @param id * @return */ SysUser selectById(Long id); /** * 查詢所有使用者 * @return */ List<SysUser> selectAll(); /** * 新增使用者 * @param sysUser * @return */ int insert(SysUser sysUser); /** * 更新使用者 * @param sysUser * @return */ int update(SysUser sysUser); /** * 根據id刪除使用者 * @param sysUser * @return */ int delete(SysUser sysUser); /** * 獲取使用者角色 * @param userId * @param enabled * @return */ List<SysRole> selectRolesByUserIdAndRoleEnabled( @Param("userId")Long userId, @Param("enabled")Integer enabled); }
UserMapper.xml對映檔案的程式碼：
<?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="tk.mybatis.simple.mapper.UserMapper">
<resultMap type="tk.mybatis.simple.model.SysUser" id="sysUserMap">
<id property="id" column="id" />
<result property="userName" column="user_name" />
<result property="userPassword" column="user_password" />
<result property="userInfo" column="user_info" />
<result property="headImg" column="head_img" />
<result property="createTime" column="create_time" jdbcType="TIMESTAMP" />
</resultMap>
<select id="selectById" resultMap="sysUserMap">
select * from sys_user where id = #{id}
</select>
<select id="selectAll" resultMap="sysUserMap">
select * from sys_user
</select>
<insert id="insert" useGeneratedKeys="true" keyProperty="id">
insert into sys_user(user_name, user_password, user_info, head_img, create_time)
values(#{userName}, #{userPassword}, #{userInfo}, #{headImg, jdbcType=BLOB}, #{createTime, jdbcType=TIMESTAMP})
</insert>
<insert id="insert2">
insert into sys_user(user_name, user_password, user_info, head_img, create_time)
values(#{userName}, #{userPassword}, #{userInfo}, #{headImg, jdbcType=BLOB}, #{createTime, jdbcType=TIMESTAMP})
<selectKey keyColumn="id" keyProperty="id" resultType="long" order="AFTER">
select last_insert_id()
</selectKey>
</insert>
<insert id="insert3">
<selectKey keyColumn="id" keyProperty="id" resultType="long" order="BEFORE">
select seq_id.nextval from dual
</selectKey>
insert into sys_user(id, user_name, user_password, user_info, head_img, create_time)
values(#{id}, #{userName}, #{userPassword}, #{userInfo}, #{headImg, jdbcType=BLOB}, #{createTime, jdbcType=TIMESTAMP})
</insert>
<update id="updateById">
update sys_user
set user_name = #{userName},
user_password = #{userPassword},
user_info = #{userInfo},
head_img = #{headImg},
create_time = #{createTime}
where id = #{id}
</update>
<delete id="deleteById">
delete from sys_user where id = #{id}
</delete>
<select id="selectRolesByUserIdAndRoleEnabled" resultType="SysRole">
select r.id, r.role_name, r.enabled, r.create_by, r.create_time
from sys_user u
inner join sys_user_role ur on u.id = ur.user_id
inner join sys_role r on ur.role_id = r.id
where u.id = #{userId} and r.enabled = #{enabled}
</select>
</mapper>UserMapperTest.Java測試程式碼
package tk.mybatis.simple.mapper;
import java.util.Date;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Assert;
import org.junit.Test;
import tk.mybatis.simple.model.SysUser;
public class UserMapperTest extends BaseMapperTest{
@Test
public void testSelectById(){
SqlSession sqlSession = this.getSqlSession();
try{
//SysUser sysUser = sqlSession.selectOne("tk.mybatis.simple.mapper.UserMapper.selectById", "1");
//獲取UserMapper介面
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
SysUser sysUser = userMapper.selectById(1L);
Assert.assertNotNull(sysUser);
System.out.printf("%-4d%4s %4s\n", sysUser.getId(), sysUser.getUserName(), sysUser.getUserPassword());
}finally{
sqlSession.close();
}
}
@Test
public void testSelectAll(){
SqlSession sqlSession = this.getSqlSession();
try{
//List<SysUser> userList = sqlSession.selectList("tk.mybatis.simple.mapper.UserMapper.selectAll");
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
List<SysUser> userList = userMapper.selectAll();
Assert.assertNotNull(userList);
Assert.assertTrue(userList.size()>0);
printUserList(userList);
}finally{
sqlSession.close();
}
}
@Test
public void testInsert(){
SqlSession sqlSession = this.getSqlSession();
try{
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
SysUser user = new SysUser();
//user.setUserName("test1");
user.setUserPassword("123456");
user.setHeadImg(new byte[]{1,2,3});
user.setCreateTime(new Date());
int result = userMapper.insert(user);
Assert.assertEquals(1, result);
//Assert.assertNull(user.getId());
}finally{
//預設的sqlSessionFactory.openSession()是不自動提交的
sqlSession.rollback();
sqlSession.close();
}
}
private void printUserList(List<SysUser> userList) {
for(SysUser sysUser : userList)
System.out.printf("%-4d%4s %4s\n", sysUser.getId(), sysUser.getUserName(), sysUser.getUserPassword());
}
}以上內容純屬個人學習筆記，如果想詳細學習mybatis，可前往http://mybatis.tk/下載相關工具及專案程式碼