抱歉，您的浏览器无法访问本站

本页面需要浏览器支持（启用）JavaScript


了解详情 >

Mybatis学习笔记3-整合与逆向工程

汤晔飞

技术知识Java

发布于：2021年3月1日

次浏览
  1. 三大框架整合.
  2. mybatis逆向工程

☀1.三大框架整合

​ 在老期的项目中，一般都是使用ssm项目做开发的，虽然现在的主流开发是springboot来做开发，但是ssm的基本整合还是需要掌握的。

☀1.导入pom文件

1、导入spring的pom依赖

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.mashibing</groupId>
    <artifactId>ssm</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/junit/junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/cglib/cglib -->
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.3.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.5</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/aopalliance/aopalliance -->
        <dependency>
            <groupId>aopalliance</groupId>
            <artifactId>aopalliance</artifactId>
            <version>1.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.21</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.48</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.0</version>
            <scope>provided</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.10.3</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.10.3</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.10.3</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.4</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.4</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.4</version>
        </dependency>

    </dependencies>
</project>

☀2.编写各个框架的配置文件

web.xml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring.xml</param-value>
    </context-param>
    <!--springmvc的核心配置类-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <!--字符编码过滤器-->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <!--支持rest风格的过滤器-->
    <filter>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

springmvc.xml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--springmvc只扫描控制器-->
    <context:component-scan base-package="com.mashibing" use-default-filters="false">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>
    <!--静态资源的扫描-->
    <mvc:default-servlet-handler></mvc:default-servlet-handler>
    <!--动态资源的扫描-->
    <mvc:annotation-driven></mvc:annotation-driven>
    <!--配置视图管理器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/page/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

spring.xml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       https://www.springframework.org/schema/tx/spring-tx.xsd
">

    <!--Spring除了控制器不扫描，其他的组件都扫描，包括service，component等-->
    <context:component-scan base-package="com.mashibing">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <!--引入外部配置文件-->
    <context:property-placeholder location="classpath:db.properties"></context:property-placeholder>
    <!--配置数据源-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="driverClassName" value="${jdbc.driverName}"></property>
        <property name="url" value="${jdbc.url}"></property>
    </bean>

    <!--配置事务管理器的bean对象-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!--开启基于注解的事务管理器的配置-->
    <tx:annotation-driven transaction-manager="transactionManager"></tx:annotation-driven>

    <!--添加mybatis的配置-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--指定配置文件的位置-->
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
        <property name="dataSource" ref="dataSource"></property>
        <property name="mapperLocations" value="classpath:com/mashibing/dao/*.xml"></property>
    </bean>
    <!--创建mybatis扫描器，批量配置映射文件-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.mashibing.dao"></property>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>
</beans>

mybatis-config.xml

1
2
3
4
5
6
7
8
9
10
11
12
<?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>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
    <typeAliases>
        <package name="com.mashibing.bean"/>
    </typeAliases>
</configuration>

db.properties

1
2
3
4
jdbc.username=root
jdbc.password=123456
jdbc.url=jdbc:mysql://192.168.85.111:3306/demo?serverTimezone=UTC
jdbc.driverName=com.mysql.jdbc.Driver

拷贝映射文件，还是位于com.mashibing.dao目录

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
<?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">
<!--namespace:编写接口的全类名，就是告诉要实现该配置文件是哪个接口的具体实现-->
<mapper namespace="com.mashibing.dao.EmpDao">
<!--    <cache></cache>-->
<!--    <cache type="org.mybatis.caches.ehcache.EhcacheCache"></cache>-->
    <!--
    select:表示这个操作是一个查询操作
    id表示的是要匹配的方法的名称
    resultType:表示返回值的类型，查询操作必须要包含返回值的类型
    #{属性名}：表示要传递的参数的名称
    -->
    <select id="findEmpByEmpno" resultType="emp">
        select * from emp where empno = #{empno}
    </select>
    <!--增删改查操作不需要返回值，增删改返回的是影响的行数，mybatis会自动做判断-->
    <insert id="insertEmp">
        insert into emp(empno,ename) values(#{empno},#{ename})
    </insert>
    <update id="updateEmp">
        update emp set ename=#{ename} where empno = #{empno}
    </update>


    <delete id="deleteEmp">
        delete from emp where empno = #{empno}
    </delete>

    <!--
    当查询语句中包含多个参数的是，如果使用#{属性名称}就无法获取具体的值了，那么应该如何使用呢？
        下面就是mybatis的参数传递方式
        1、如果是单个参数，
            基本类型：使用#{随便写}
            引用类型：使用#{类的属性名称}
        2、多个参数：
            当查询的时候传入多个参数的时候，就无法简单的通过#{参数名}来获取值了，
            只能通过arg0,arg1...或者param1,param2等方式来获取值
            原因就在于，mybatis在传入多个参数的时候，会将这些参数封装到一个map中，此时map中的key就是
            arg0,arg1,param1,param2这些值，但是很明显，这样的传值方式不是很友好，没有办法根据参数的名称来
            获取具体的值，因此可以使用如下的方式来指定参数的key是什么
            Emp selectEmpByNoAndName(@Param("empno") Integer empno, @Param("ename") String ename);
                也就是通过@Param来指定存入map中的key值是什么
        3、使用map来传递参数：
                依然是直接使用#{key}来获取具体的属性值
    -->

    <!--
        当使用#{}来获取值的时候会发现打印的sql语句如下：
            select * from emp where empno=? and ename=?
        当使用${}来获取值的时候会发现打印的sql语句如下：
            select * from emp where empno=7369 and ename='SMITH'
        通过刚刚的案例大家已经发现了存在的问题了，
        使用#{}方式进行取值：采用的是参数预编译的方式，参数的位置使用？进行替代，不会出现sql注入的问题
        使用${}方式进行取值：采用的是直接跟sql语句进行拼接的方式
    -->
    <select id="selectEmpByNoAndName" resultType="com.mashibing.bean.Emp">
        select * from ${t} where empno=${empno} and ename=${ename}
    </select>

    <select id="selectEmpByNoAndName2" resultType="com.mashibing.bean.Emp">
        select * from emp where empno=#{empno} and ename=#{ename}
    </select>

    <!--当返回值的结果是集合的时候，返回值的类型依然写的是集合中具体的类型-->
    <select id="selectAllEmp" resultType="com.mashibing.bean.Emp">
        select  * from emp
    </select>

    <!--在查询的时候可以设置返回值的类型为map，当mybatis查询完成之后会把列的名称作为key
    列的值作为value，转换到map中
    -->
    <select id="selectEmpByEmpReturnMap" resultType="map">
        select * from emp where empno = #{empno}
    </select>

    <!--注意，当返回的结果是一个集合对象的是，返回值的类型一定要写集合具体value的类型
    同时在dao的方法上要添加@MapKey的注解，来设置key是什么结果
    @MapKey("empno")
    Map<Integer,Emp> getAllEmpReturnMap();-->
    <select id="getAllEmpReturnMap" resultType="com.mashibing.bean.Emp">
        select * from emp
    </select>

    <!--再做查询的时候，有时候需要关联其他对象，因此需要使用关联查询
    可以通过下面自定义结果集的方式实现
    -->
    <select id="selectEmpAndDept" resultMap="empDept">
        select * from emp left join dept on emp.deptno = dept.deptno where empno = #{empno};
    </select>
    <!--<resultMap id="empDept" type="com.mashibing.bean.Emp">
        <id column="empno" property="empno"></id>
        <result column="ename" property="ename"></result>
        <result column="job" property="job"></result>
        <result column="mgr" property="mgr"></result>
        <result column="hiredate" property="hiredate"></result>
        <result column="sal" property="sal"></result>
        <result column="comm" property="common"></result>
        <result column="deptno" property="dept.deptno"></result>
        <result column="dname" property="dept.dname"></result>
        <result column="loc" property="dept.loc"></result>
    </resultMap>-->

    <!--在mybatis中还提供了一种简单的形式，使用association标签可以搞定
    -->
    <resultMap id="empDept" type="com.mashibing.bean.Emp">
        <id column="empno" property="empno"></id>
        <result column="ename" property="ename"></result>
        <result column="job" property="job"></result>
        <result column="mgr" property="mgr"></result>
        <result column="hiredate" property="hiredate"></result>
        <result column="sal" property="sal"></result>
        <result column="comm" property="common"></result>
        <association property="dept" javaType="com.mashibing.bean.Dept">
            <id column="deptno" property="deptno"></id>
            <result column="dname" property="dname"></result>
            <result column="loc" property="loc"></result>
        </association>
    </resultMap>

    <select id="selectEmpAndDeptBySimple" resultMap="simpleEmpAndDept">
        select * from emp where empno = #{empno}
    </select>
    <resultMap id="simpleEmpAndDept" type="com.mashibing.bean.Emp">
        <id column="empno" property="empno"></id>
        <result column="ename" property="ename"></result>
        <result column="job" property="job"></result>
        <result column="mgr" property="mgr"></result>
        <result column="hiredate" property="hiredate"></result>
        <result column="sal" property="sal"></result>
        <result column="comm" property="common"></result>
        <association property="dept" select="com.mashibing.dao.DeptDao.getDeptAndEmpsBySimple" column="deptno" fetchType="eager">
        </association>
    </resultMap>

    <select id="selectEmpByStep" resultType="com.mashibing.bean.Emp">
        select * from emp where deptno = #{deptno}
    </select>

   <!-- <select id="getEmpByCondition" resultType="com.mashibing.bean.Emp">
        select * from emp
        <where>
            <if test="empno!=null">
                empno > #{empno}
            </if>
            <if test="ename!=null">
                and ename like #{ename}
            </if>
            <if test="sal!=null">
                and sal > #{sal}
            </if>
        </where>-->
    <!--
    trim截取字符串：
    prefix：前缀，为sql整体添加一个前缀
    prefixOverrides:去除整体字符串前面多余的字符
    suffixOverrides:去除后面多余的字符串
    -->
    <select id="getEmpByCondition" resultType="com.mashibing.bean.Emp">
        select * from emp

        <trim prefix="where" prefixOverrides="and" suffixOverrides="and">
            <if test="empno!=null">
                empno > #{empno} and
            </if>
            <if test="ename!=null">
                ename like #{ename} and
            </if>
            <if test="sal!=null">
                sal > #{sal} and
            </if>
        </trim>
    </select>

    <!--foreach是对集合进行遍历
    collection="deptnos"  指定要遍历的集合
    close="" 表示以什么结束
    index="" 给定一个索引值
    item=""  遍历的每一个元素的值
    open=""  表示以什么开始
    separator="" 表示多个元素的分隔符
    -->
    <select id="getEmpByDeptnos" resultType="Emp">
        select * from emp where deptno in
        <foreach collection="deptnos" close=")" index="idx" item="deptno" open="(" separator=",">
            #{deptno}
        </foreach>
    </select>

    <select id="getEmpByConditionChoose" resultType="com.mashibing.bean.Emp">
        select * from emp
        <where>
            <choose>
                <when test="empno!=null">
                    empno > #{empno}
                </when>
                <when test="ename!=null">
                    ename like #{ename}
                </when>
                <when test="sal!=null">
                    sal > #{sal}
                </when>
                <otherwise>
                    1=1
                </otherwise>
            </choose>
        </where>
    </select>
    <update id="updateEmpByEmpno">
        update emp
        <set>
            <if test="empno!=null">
                empno=#{empno},
            </if>
            <if test="ename!=null">
                ename = #{ename},
            </if>
            <if test="sal!=null">@
                sal = #{sal}
            </if>
        </set>
        <where>
            empno = #{empno}
        </where>
    </update>

</mapper>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
<?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="com.mashibing.dao.DeptDao">
    <!--定义查询集合元素-->
    <select id="getDeptAndEmps" resultMap="deptEmp">
        select * from dept left join emp on dept.deptno = emp.deptno where dept.deptno=#{deptno}
    </select>
    <resultMap id="deptEmp" type="com.mashibing.bean.Dept">
        <id property="deptno" column="deptno"></id>
        <result property="dname" column="dname"></result>
        <result property="loc" column="loc"></result>
        <!--封装集合类的元素
            property：指定集合的属性
            ofType:指定集合中的元素类型
        -->
        <collection property="emps" ofType="com.mashibing.bean.Emp">
            <id property="empno" column="empno"></id>
            <result column="ename" property="ename"></result>
            <result column="job" property="job"></result>
            <result column="mgr" property="mgr"></result>
            <result column="hiredate" property="hiredate"></result>
            <result column="sal" property="sal"></result>
            <result column="comm" property="common"></result>
        </collection>
    </resultMap>

    <select id="getDeptAndEmpsBySimple" resultType="com.mashibing.bean.Dept">
        select * from dept where deptno = #{deptno}
    </select>

    <select id="getDeptAndEmpsByStep" resultMap="deptEmpByStep">
        select * from dept where deptno = #{deptno}
    </select>
    <resultMap id="deptEmpByStep" type="com.mashibing.bean.Dept">
        <id property="deptno" column="deptno"></id>
        <result property="dname" column="dname"></result>
        <result property="loc" column="loc"></result>
        <!--封装集合类的元素
            property：指定集合的属性
            ofType:指定集合中的元素类型
        -->
        <collection property="emps" ofType="com.mashibing.bean.Emp" select="com.mashibing.dao.EmpDao.selectEmpByStep" column="deptno" >
        </collection>
    </resultMap>
</mapper>

添加dao的接口

EmpDao.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
package com.mashibing.dao;

import com.mashibing.bean.Emp;
import org.apache.ibatis.annotations.MapKey;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface EmpDao {

    public Emp findEmpByEmpno(Integer empno);

    public int updateEmp(Emp emp);

    public int deleteEmp(Integer empno);

    public int insertEmp(Emp emp);

    Emp selectEmpByNoAndName(@Param("empno") Integer empno, @Param("ename") String ename, @Param("t") String tablename);
    Emp selectEmpByNoAndName2(Map<String, Object> map);

    List<Emp> selectAllEmp();

    Map<String,Object> selectEmpByEmpReturnMap(Integer empno);

    @MapKey("empno")
    Map<Integer,Emp> getAllEmpReturnMap();

    Emp selectEmpAndDept(Integer empno);
    Emp selectEmpAndDeptBySimple(Integer empno);
    List<Emp> selectEmpByStep(Integer deptno);

    public List<Emp> getEmpByCondition(Emp emp);
    public List<Emp> getEmpByConditionChoose(Emp emp);
    public List<Emp> getEmpByDeptnos(@Param("deptnos") List<Integer> deptnos);

    public int updateEmpByEmpno(Emp emp);

}

☀3.创建测试类

TestController.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
package com.mashibing.controller;

import com.mashibing.bean.Emp;
import com.mashibing.dao.EmpDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class TestController {

    @Autowired
    EmpDao empDao;

    @RequestMapping("/test")
    public String test(){
        System.out.println("test");
        Emp empByEmpno = empDao.findEmpByEmpno(7369);
        System.out.println(empByEmpno);
        return "success";
    }
}

☀2.mybatis逆向工程

引入pom依赖

1
2
3
4
5
6
<!-- https://mvnrepository.com/artifact/org.mybatis.generator/mybatis-generator-core -->
<dependency>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-core</artifactId>
    <version>1.4.0</version>
</dependency>

编写配置文件：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
<!DOCTYPE generatorConfiguration PUBLIC
        "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <context id="simple" targetRuntime="MyBatis3">
        <!--指向数据库连接-->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://192.168.85.111:3306/demo?serverTimezone=UTC"
                        userId="root"
                        password="123456"
        />

        <!--生成对应的实体类
        targetPackage：指定生成java文件的目录
        targetProject：放在那个工程的哪个目录下
        -->
        <javaModelGenerator targetPackage="com.mashibing.bean" targetProject="src/main/java"/>

        <!--SQL映射文件生成器
        targetPackage：指定生成java文件的目录
        targetProject：放在那个工程的哪个目录下
        -->
        <sqlMapGenerator targetPackage="com.mashibing.dao" targetProject="src/main/resources"/>

        <!--dao接口生成器-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.mashibing.dao" targetProject="src/main/java"/>

        <!--指定要逆向生成的数据表
        tableName:表名
        domainObjectName:对象名
        -->
        <table tableName="emp" domainObjectName="Emp" enableCountByExample="false" enableDeleteByExample="false" enableUpdateByExample="false" selectByExampleQueryId="false" enableSelectByExample="false"/>
        <table tableName="dept" domainObjectName="Dept" enableCountByExample="false" enableDeleteByExample="false" enableUpdateByExample="false" selectByExampleQueryId="false" enableSelectByExample="false"/>
    </context>
</generatorConfiguration>

编写测试类

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
package com.mashibing;

import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.exception.InvalidConfigurationException;
import org.mybatis.generator.exception.XMLParserException;
import org.mybatis.generator.internal.DefaultShellCallback;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class Test {
    public static void main(String[] args) throws IOException, XMLParserException, InvalidConfigurationException, SQLException, InterruptedException {
        List<String> warnings = new ArrayList<String>();
        boolean overwrite = true;
        File configFile = new File("mbg.xml");
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(configFile);
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        myBatisGenerator.generate(null);

    }
}

☀3.分页插件 PageHelper（自学，项目中会使用）

博客内容遵循 署名-非商业性使用-相同方式共享 4.0 国际 (CC BY-NC-SA 4.0) 协议

本文永久链接是：http://aner1001.gitee.io/posts/2021/03/01/918150132c1d/

更新于：2021年3月1日

Mybatis

评论