MyBatis框架入门

时间：2019-12-15 16:29:44 阅读：67 评论：0 收藏：0 [点我收藏+]

标签：junit session source 数据 delete ali lap 修改 git

MyBatis架构与项目搭建

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● 导入Jar

数据库驱动包：mysql-connector-java-5.1.46-bin.jar

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mybatis核心包：mybatis-3.4.6.jar

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mybatis依赖：

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● 准备数据库

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● db.properties - mysql驱动配置文件（这样可以优化性能）

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/games_db?useUnicode=true&characterEncoding=UTF-8&useSSL=true
jdbc.username=root
jdbc.password=123456

View Code

● 引入log4j.properties文件（测试输出需要）

● 添加mybatis映射配置文件 - sqlMapConfig.xml

配置文件中主要是配置连接数据库和事务管理的内容，文件名可以自定义，默认SqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 引入外部配置文件 -->
    <properties resource="db.properties"></properties>
    <!-- 配置别名;推荐使用package包形式来配置别名;包的形式会扫描主包及子包中所有文件;以对象类名为别名,大小写不限,推荐使用小写 -->
    <typeAliases>
        <!-- <typeAlias type="com.sikiedu.beans.User" alias="user" /> -->
        <package name="com.sikiedu.beans" />
    </typeAliases>
    <!-- 配置mybatis运行环境 ; 在集成Spring是不用 -->
    <environments default="development">
        <environment id="development">
            <!-- type="JDBC" 代表使用JDBC的提交和回滚来管理事务 -->
            <transactionManager type="JDBC" />
            <!-- 使用连接池连接数据库 - mybatis提供了3种数据源类型，分别是：POOLED,UNPOOLED,JNDI -->
            <!-- POOLED 表示支持JDBC数据源连接池 ; UNPOOLED 表示不支持数据源连接池 ; JNDI 表示支持外部数据源连接池 -->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}" />
                <property name="url" value="${jdbc.url}" />
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
    </environments>
    <!--配置映射器的位置 -->
    <mappers>
        <!-- 单个配置 -->
        <!-- <mapper resource="com/sikiedu/mapper/UserMapper.xml" /> -->
        <!-- <mapper url="file:\\\D:\Java\WorkSpace\JavaEE_SSM_Test\ssm_mybatis\src\com\sikiedu\mapper\UserMapper.xml" /> -->
        <!-- <mapper class="com.sikiedu.mapper.UserMapper" /> -->
        <!-- 多配置-以包的形式;推荐使用 -->
        <package name="com.sikiedu.mapper" />
    </mappers>
</configuration>

● 创建数据库对应的实体对象

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数据库实体对象

 1 package com.sikiedu.beans;
 2 
 3 public class Role {
 4 
 5     private Integer id;
 6     private String name;
 7     private Integer level;
 8     private String roletype;
 9     private Integer userid;
10 
11     public Integer getId() {
12         return id;
13     }
14 
15     public void setId(Integer id) {
16         this.id = id;
17     }
18 
19     public String getName() {
20         return name;
21     }
22 
23     public void setName(String name) {
24         this.name = name;
25     }
26 
27     public Integer getLevel() {
28         return level;
29     }
30 
31     public void setLevel(Integer level) {
32         this.level = level;
33     }
34 
35     public String getRoletype() {
36         return roletype;
37     }
38 
39     public void setRoletype(String roletype) {
40         this.roletype = roletype;
41     }
42 
43     public Integer getUserid() {
44         return userid;
45     }
46 
47     public void setUserid(Integer userid) {
48         this.userid = userid;
49     }
50 
51     @Override
52     public String toString() {
53         return "Role [id=" + id + ", name=" + name + ", level=" + level + ", roletype=" + roletype + ", userid="
54                 + userid + "]";
55     }
56 
57 }

Role.java

 1 package com.sikiedu.beans;
 2 
 3 import java.util.Date;
 4 
 5 public class User {
 6 
 7     private Integer id;
 8     private String username;
 9     private String userpassword;
10     private Float balance;
11     private String grgisterdate;
12 
13     public Integer getId() {
14         return id;
15     }
16 
17     public void setId(Integer id) {
18         this.id = id;
19     }
20 
21     public String getUsername() {
22         return username;
23     }
24 
25     public void setUsername(String username) {
26         this.username = username;
27     }
28 
29     public String getUserpassword() {
30         return userpassword;
31     }
32 
33     public void setUserpassword(String userpassword) {
34         this.userpassword = userpassword;
35     }
36 
37     public Float getBalance() {
38         return balance;
39     }
40 
41     public void setBalance(Float balance) {
42         this.balance = balance;
43     }
44 
45     public String getGrgisterdate() {
46         return grgisterdate;
47     }
48 
49     public void setGrgisterdate(String grgisterdate) {
50         this.grgisterdate = grgisterdate;
51     }
52 
53     @Override
54     public String toString() {
55         return "User [id=" + id + ", username=" + username + ", userpassword=" + userpassword + ", balance=" + balance
56                 + ", grgisterdate=" + grgisterdate + "]";
57     }
58 
59 }

User.java

Vo为关联查询需要 - 一对一、一对多

 1 package com.sikiedu.beans;
 2 
 3 import java.util.List;
 4 
 5 public class RoleVo extends Role {
 6 
 7     private User user;
 8     private List<Integer> idList;
 9 
10     public User getUser() {
11         return user;
12     }
13 
14     public void setUser(User user) {
15         this.user = user;
16     }
17 
18     public List<Integer> getList() {
19         return idList;
20     }
21 
22     public void setList(List<Integer> idList) {
23         this.idList = idList;
24     }
25 
26     @Override
27     public String toString() {
28         return "RoleVo [ID=" + getId() + "\t name=" + getName() + "\t roletype=" + getRoletype() + "\t user=" + user
29                 + "]";
30     }
31 
32 }

RoleVo.java

 1 package com.sikiedu.beans;
 2 
 3 import java.util.List;
 4 
 5 public class UserVo extends User {
 6     // 维护一个Role集合
 7     private List<Role> roleList;
 8 
 9     public List<Role> getRole() {
10         return roleList;
11     }
12 
13     public void setRole(List<Role> roleList) {
14         this.roleList = roleList;
15     }
16 
17     @Override
18     public String toString() {
19         return "UserVo [ID=" + getId() + "\t username=" + getUsername() + "\t Grgisterdate=" + getGrgisterdate()
20                 + "\t role=" + roleList + "]";
21     }
22 
23 }

UserVo.java

● 创建方法接口XxxxMapper.java And 定义操作数据表的sql映射文件XxxMapper.xml

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创建方法接口 - 提供简单的增删改查数据信息。

 1 package com.sikiedu.mapper;
 2 
 3 import java.util.List;
 4 
 5 import com.sikiedu.beans.Role;
 6 import com.sikiedu.beans.RoleVo;
 7 
 8 public interface RoleMapper {
 9 
10     // 查询所有
11     public List<Role> selectAllRole();
12 
13     // 通过RoleVo一对一关联查询
14     public List<RoleVo> selectAllRoleVo();
15 
16     // 多条件查询 通过角色对象中的条件查询角色表
17     public List<Role> selectRoleListByRole(Role role);
18 
19     // 多条件查询 通过角色对象中的条件查询角色表Trim
20     public List<Role> selectRoleListByTrim(Role role);
21 
22     // 更新角色表
23     public void updateSetRole(Role role);
24 
25     // 使用多个ID获取角色列表 By array
26     public List<Role> selectRoleListByids(Integer[] ids);
27 
28     // 使用多个ID获取角色列表 By list
29     public List<Role> selectRoleListByList(List<Integer> idList);
30 
31     // 使用多个ID获取角色列表 By RoleVo
32     public List<Role> selectRoleListByRoleVo(RoleVo roleVo);
33 
34 }

RoleMapper.java

 1 package com.sikiedu.mapper;
 2 
 3 import java.util.List;
 4 
 5 import com.sikiedu.beans.User;
 6 import com.sikiedu.beans.UserVo;
 7 
 8 public interface UserMapper {
 9 
10     // 根据ID查询用户
11     public User selectUserById(Integer id);
12 
13     // 根据用户名模糊查询用户
14     public List<User> selectUserLikeUsername(String username);
15 
16     // 同过包装类UserVo查询用户
17     public User selectUserByUserVoId(UserVo vo);
18 
19     // 查询用户总条数
20     public Integer selectUserCount();
21 
22     // 查询所有用户包装类
23     public List<UserVo> selectAllUserVo();
24 }

UserMapper.java

定义操作数据表的sql映射文件

  1 <?xml version="1.0" encoding="UTF-8" ?>
  2 <!DOCTYPE mapper
  3   PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  4   "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  5 <mapper namespace="com.sikiedu.mapper.RoleMapper">
  6 
  7     <sql id="myselect">
  8         SELECT *
  9         FROM role
 10     </sql>
 11 
 12     <resultMap type="Role" id="roleRM">
 13         <id property="id" column="idrole" />
 14     </resultMap>
 15     <select id="selectAllRole" resultMap="roleRM">
 16         <include refid="myselect"></include>
 17     </select>
 18 
 19     <resultMap type="RoleVo" id="roleVo">
 20         <id property="id" column="idrole" />
 21         <result property="name" column="name" />
 22         <result property="level" column="level" />
 23         <result property="roletype" column="roletype" />
 24         <!-- 一对一关系 -->
 25         <association property="user" javaType="User">
 26             <id property="id" column="id" />
 27             <result property="username" column="username" />
 28         </association>
 29     </resultMap>
 30     <!-- 一对一关联查询 -->
 31     <select id="selectAllRoleVo" resultMap="roleVo">
 32         SELECT
 33         r.idrole,
 34         r.name,
 35         r.level,
 36         r.roletype,
 37         u.id,
 38         u.username
 39         FROM role r
 40         LEFT JOIN user u
 41         ON r.idrole = u.id
 42     </select>
 43 
 44     <!-- 多条件查询 通过角色对象中的条件查询角色表 -->
 45     <select id="selectRoleListByRole" parameterType="Role" resultMap="roleRM">
 46         <include refid="myselect"></include>
 47         <where>
 48             <if test="level!=null and level!=‘‘">
 49                 level = #{level}
 50             </if>
 51             <if test="roletype!=null and roletype!=‘‘">
 52                 AND roletype = #{roletype}
 53             </if>
 54             <if test="userid!=null">
 55                 AND userid = #{userid}
 56             </if>
 57         </where>
 58     </select>
 59 
 60     <!--多条件查询 通过角色对象中的条件查询角色表Trim -->
 61     <select id="selectRoleListByTrim" parameterType="Role" resultMap="roleRM">
 62         <include refid="myselect"></include>
 63         <trim prefix="WHERE" suffixOverrides="AND">
 64             <if test="level!=null and level!=‘‘">
 65                 level = #{level} AND
 66             </if>
 67             <if test="roletype!=null and roletype!=‘‘">
 68                 roletype = #{roletype} AND
 69             </if>
 70             <if test="userid!=null">
 71                 userid = #{userid}
 72             </if>
 73         </trim>
 74     </select>
 75 
 76     <!-- 更新角色表 -->
 77     <update id="updateSetRole" parameterType="Role">
 78         UPDATE role
 79         <set>
 80             <if test="name != null and name != ‘‘">
 81                 name = ‘${name}‘,
 82             </if>
 83             <if test="level != null">
 84                 level = ${level},
 85             </if>
 86             <if test="roletype != null and roletype != ‘‘">
 87                 roletype = ‘${roletype}‘,
 88             </if>
 89             <if test="userid != null">
 90                 userid = ${userid}
 91             </if>
 92         </set>
 93         WHERE
 94         idrole = #{id}
 95     </update>
 96 
 97     <!-- 使用多个ID获取角色列表 foreach遍历数组 -->
 98     <select id="selectRoleListByids" resultMap="roleRM">
 99         <include refid="myselect"></include>
100         WHERE idrole IN
101         <foreach collection="array" item="id" open="(" separator="," close=")">
102             ${id}
103         </foreach>
104     </select>
105 
106     <!-- 使用多个ID获取角色列表 foreach遍历集合 -->
107     <select id="selectRoleListByList" resultMap="roleRM">
108         <include refid="myselect"></include>
109         WHERE idrole IN
110         <foreach collection="list" item="id" open="(" separator="," close=")">
111             ${id}
112         </foreach>
113     </select>
114 
115     <select id="selectRoleListByRoleVo" resultMap="roleRM">
116         <include refid="myselect"></include>
117         WHERE idrole IN
118         <foreach collection="list" item="id" open="(" separator="," close=")">
119             ${id}
120         </foreach>
121     </select>
122     
123 </mapper>

RoleMapper.xml

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper
 3   PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4   "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5 <mapper namespace="com.sikiedu.mapper.UserMapper">
 6 
 7     <!-- 查询用户 -->
 8     <select id="selectUserById" parameterType="Integer" resultType="com.sikiedu.beans.User">
 9         SELECT * FROM user WHERE id = #{id}
10     </select>
11     <!-- #{}占位符 尽量选用#{}来解决问题 -->
12     <!-- ${}字符拼接 or1=1 容易被SQL注入 -->
13     <select id="selectUserLikeUsername" parameterType="String" resultType="User">
14         <!-- SELECT * FROM coke.user WHERE username LIKE ‘%${value}%‘ -->
15         SELECT * FROM user WHERE username LIKE "%"#{username}"%"
16     </select>
17 
18     <!-- 添加用户 -->
19     <insert id="insertUser" parameterType="com.sikiedu.beans.User">
20         INSERT INTO user VALUES(null,#{username},#{userpassword},#{balance},#{grgisterdate})
21     </insert>
22 
23     <!-- 修改用户 -->
24     <update id="updateUser" parameterType="com.sikiedu.beans.User">
25         UPDATE user SET username = #{username} WHERE id = #{id}
26     </update>
27 
28     <!-- 删除用户 -->
29     <delete id="deleteUserById" parameterType="Integer">
30         DELETE FROM user WHERE id = #{id}
31     </delete>
32 
33     <!-- 同过包装类UserVo查询用户 -->
34     <select id="selectUserByUserVoId" parameterType="UserVo" resultType="user">
35         SELECT * FROM user WHERE id = #{id}
36     </select>
37 
38     <!-- selectUserCount -->
39     <select id="selectUserCount" resultType="Integer">
40         SELECT COUNT(*) FROM user
41     </select>
42 
43     <resultMap type="UserVo" id="userVo">
44         <id property="id" column="id" />
45         <result property="username" column="username" />
46         <result property="grgisterdate" column="grgisterdate" />
47         <!-- 一对多关系 -->
48         <collection property="roleList" ofType="Role">
49             <id property="id" column="idrole" />
50             <result property="name" column="name" />
51             <result property="roletype" column="roletype" />
52         </collection>
53     </resultMap>
54     <!-- 一对多关联查询 -->
55     <select id="selectAllUserVo" resultMap="userVo">
56         SELECT
57         u.id,
58         u.username,
59         u.grgisterdate,
60         r.idrole,
61         r.name,
62         r.roletype
63         FROM user u
64         LEFT JOIN role r
65         ON u.id = r.userid
66     </select>
67 
68 </mapper>

UserMapper.xml

映射配置文件里注册映射文件

1 <!--配置映射器的位置 -->
2 <mappers>
3     <!-- 单个配置 -->
4     <!-- <mapper resource="com/sikiedu/mapper/UserMapper.xml" /> -->
5     <!-- <mapper url="file:\\\D:\Java\WorkSpace\JavaEE_SSM_Test\ssm_mybatis\src\com\sikiedu\mapper\UserMapper.xml" /> -->
6     <!-- <mapper class="com.sikiedu.mapper.UserMapper" /> -->
7     <!-- 自动扫描包内的Mapper接口与配置文件 - 以包的形式;推荐使用 -->
8     <package name="com.sikiedu.mapper" />
9 </mappers>

测试 - Dao原始开发方式

1 package com.sikiedu.dao;
2 
3 import com.sikiedu.beans.User;
4 
5 public interface UserDao {
6 
7     public User getUserById(Integer id);
8 
9 }

UserDao.java

 1 package com.sikiedu.dao;
 2 
 3 import org.apache.ibatis.session.SqlSession;
 4 import org.apache.ibatis.session.SqlSessionFactory;
 5 
 6 import com.sikiedu.beans.User;
 7 
 8 public class UserDaoImpl implements UserDao {
 9 
10     // SQLSession工厂
11     private SqlSessionFactory ssf;
12 
13     // 通过构造给ssf赋值
14     public UserDaoImpl(SqlSessionFactory ssf) {
15         super();
16         this.ssf = ssf;
17     }
18 
19     @Override
20     public User getUserById(Integer id) {
21         // 生产一个session
22         SqlSession sqlSession = ssf.openSession();
23         // 操作数据库
24         return sqlSession.selectOne("selectUserById", id);
25     }
26 
27 }

UserDaoImpl.java

 1 package com.sikiedu.test;
 2 
 3 import java.io.IOException;
 4 import java.io.InputStream;
 5 
 6 import org.apache.ibatis.io.Resources;
 7 import org.apache.ibatis.session.SqlSessionFactory;
 8 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 9 import org.junit.Test;
10 
11 import com.sikiedu.beans.User;
12 import com.sikiedu.dao.UserDaoImpl;
13 
14 public class UserDaoTest {
15 
16     // sqlSession工厂
17     private static SqlSessionFactory ssf;
18 
19     static {
20         String resource = "sqlMapConfig.xml";
21         try {
22             // 读取配置文件
23             InputStream inputStream = Resources.getResourceAsStream(resource);
24             // 创建sqlSession工厂
25             ssf = new SqlSessionFactoryBuilder().build(inputStream);
26         } catch (IOException e) {
27             e.printStackTrace();
28         }
29     }
30 
31     @Test // 根据ID查询用户
32     public void DaoTest() {
33 
34         UserDaoImpl dao = new UserDaoImpl(ssf);
35         User user = dao.getUserById(1);
36         System.out.println(user);
37     }
38 }

UserDaoTest.java

增删改查操作

读取配置文件，创建sqlSessionFactory，获取sqlSession

// 读取配置文件
String resource = "sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);

// 需要sqlSessionFactoryBuilder
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder();

// 创建sqlSessionFactory
SqlSessionFactory ssf = ssfb.build(in);

// 生产一个sqlSession
SqlSession sqlSession = ssf.openSession();

♦ 增

<insert id="insertUser" parameterType="com.sikiedu.beans.User">
    INSERT INTO user VALUES(null,#{username},#{userpassword},#{balance},#{grgisterdate})
</insert>

User user = new User();
user.setUsername("天猫");
user.setUserpassword("123456");
user.setBalance(Float.valueOf(1000));
user.setGrgisterdate(new SimpleDateFormat("yyyy-MM-dd").format(new Date(System.currentTimeMillis())));
sqlSession.insert("com.sikiedu.mapper.UserMapper.insertUser", user);
sqlSession.commit();

♦ 删

<delete id="deleteUserById" parameterType="Integer">
    DELETE FROM user WHERE id = #{id}
</delete>

sqlSession.delete("com.sikiedu.mapper.UserMapper.deleteUserById", 100);
sqlSession.commit();

♦ 改

<update id="updateUser" parameterType="com.sikiedu.beans.User">
    UPDATE user SET username = #{username} WHERE id = #{id}
</update>

User user = new User();
user.setId(44);
user.setUsername("阿羊");
sqlSession.update("com.sikiedu.mapper.UserMapper.updateUser", user);
sqlSession.commit();

♦ 查

<!-- #{}占位符 尽量选用#{}来解决问题 -->
<!-- ${}字符拼接 or1=1 容易被SQL注入 -->
<select id="selectUserById" parameterType="Integer" resultType="com.sikiedu.beans.User">
    SELECT * FROM user WHERE id = #{id}
</select>
<select id="selectUserLikeUsername" parameterType="String" resultType="User">
    <!-- SELECT * FROM coke.user WHERE username LIKE ‘%${value}%‘ -->
    SELECT * FROM user WHERE username LIKE "%"#{username}"%"
</select>

// 查询用户
// 操作数据库;参数1-要操作的sql语句；参数2-sql语句参数
User user = sqlSession.selectOne("com.sikiedu.mapper.UserMapper.selectUserById", 3);
System.out.println(user);

// 通过username模糊 查询用户
List<User> users = sqlSession.selectList("com.sikiedu.mapper.UserMapper.selectUserLikeUsername", "天");
for (User user : users) {
    System.out.println(user);
}

MyBatis框架入门

标签：junit session source 数据 delete ali lap 修改 git

原文地址：https://www.cnblogs.com/Dm920/p/12041438.html

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