SSM framework integration, simple case

1、SSM Introduction to the framework

SSM（Spring+SpringMVC+MyBatis） The frameset is made up of Spring、MyBatis Integration of two open source frameworks （SpringMVC yes Spring Part of ）, Often used as a simple data source web Project framework .

Spring

        Spring It's like assembling the whole project bean Big factory of , In the configuration file, you can specify to use specific parameters to call the constructor of entity class to instantiate the object . It can also be called the adhesive in the project .

        Spring The core idea of IoC（ Inversion of control ）, That is, there is no need for programmers to explicitly `new` An object , Rather let Spring The framework helps you do all this .

SpringMVC

        SpringMVC Intercept user requests in the project , The core of it Servlet namely DispatcherServlet Take on the role of an intermediary or front desk , Pass the user request through HandlerMapping To match Controller,Controller It is the specific operation corresponding to the request .SpringMVC amount to SSH In the frame struts.

mybatis

        mybatis It's right jdbc Encapsulation , It makes the underlying operations of the database transparent .mybatis The operations are all around a sqlSessionFactory Examples expand .mybatis Through the configuration file associated with each entity class Mapper file ,Mapper The file configures what each class needs to do with the database sql Statements mapping . Every time you interact with the database , adopt sqlSessionFactory To get a sqlSession, Re execution sql command .

         Page send request to controller , The controller calls the business layer processing logic , The logic layer sends requests to the persistence layer , The persistence layer interacts with the database , Then return the result to the business layer , The business layer sends the processing logic to the controller , The controller calls the view to display the data .

2、 Integrate SSM frame

（1） Create a maven-web project , Replace WEB-INF Inside web.xml file

<?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">
    
</web-app>

（2） Add dependencies

<dependencies>
    <!-- Paging plug-ins -->
    <dependency>
      <groupId>com.github.pagehelper</groupId>
      <artifactId>pagehelper</artifactId>
      <version>5.3.0</version>
    </dependency>
    <!--spring-webmvc-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.15.RELEASE</version>
    </dependency>

    <!--mybatis rely on -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.6</version>
    </dependency>

    <!--mybatis and spring Integration dependency -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>2.0.6</version>
    </dependency>

    <!--mysql drive -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.28</version>
    </dependency>

    <!--druid Connection pool dependency -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.2.1</version>
    </dependency>

    <!--lombok rely on -->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.24</version>
    </dependency>

    <!--jackson java Object to json object  @ResponseBody-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.13.2.2</version>
    </dependency>

    <!--servlet-api rely on -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
    </dependency>

    <!--spring-jdbc rely on   Parsing data source configuration -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.15.RELEASE</version>
    </dependency>

    <!--mybatis-generator Code generator -->
    <dependency>
      <groupId>org.mybatis.generator</groupId>
      <artifactId>mybatis-generator-core</artifactId>
      <version>1.4.0</version>
    </dependency>

    <!--junit unit testing -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>

    <!-- Upload to OSS Cloud server -->
    <dependency>
      <groupId>com.aliyun.oss</groupId>
      <artifactId>aliyun-sdk-oss</artifactId>
      <version>3.13.0</version>
    </dependency>

    <!--log4j  journal -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

    <!--slf4j-->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.30</version>
    </dependency>

    <!-- Upload files -->
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.4</version>
    </dependency>
  </dependencies>

（3） To write spring Configuration file for

<?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">
    <!-- Package scanning -->
    <context:component-scan base-package="com.gjx"/>
    <!-- Turn on special annotation scanning -->
    <mvc:annotation-driven/>
    <!-- Static resource release -->
    <mvc:default-servlet-handler/>
    <!-- Configure login interceptor -->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <mvc:exclude-mapping path="/user/login"/>
            <mvc:exclude-mapping path="/user/register"/>
            <mvc:exclude-mapping path="css/**"/>
            <mvc:exclude-mapping path="js/**"/>
            <mvc:exclude-mapping path="images/**"/>
            <bean class="com.gjx.interceptor.LoginInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>
    <!-- Upload files  id Name must be multipartResolver-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- Maximum upload size , Unit is byte-->
        <property name="maxUploadSize" value="10485760"/>
    </bean>
    <!--spring To configure -->
    <!-- Data source configuration -->
    <bean id="druidDataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <!-- Database driven -->
        <property name="url" value="jdbc:mysql://localhost:3306/vue01?serverTimezone=Asia/Shanghai"/>
        <property name="username" value="root"/>
        <property name="password" value="990412"/>
        <!-- The number of connections initializing the connection pool -->
        <property name="initialSize" value="5"/>
        <!-- Minimum number of idle -->
        <property name="minIdle" value="5"/>
        <!-- maximum connection -->
        <property name="maxActive" value="10"/>
        <!-- The maximum waiting time unit is milliseconds -->
        <property name="maxWait" value="3000"/>
    </bean>
    <!--sqlSessionFactory  Integrate mybatis-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- Alias package -->
        <property name="typeAliasesPackage" value="com.gjx.entity"/>
        <!-- Data source configuration -->
        <property name="dataSource" ref="druidDataSource"/>
        <!--mapper Storage location of mapping file -->
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>
        <!--plugins plug-in unit ,array type , Paging plug-ins -->
        <property name="plugins">
            <array>
                <bean class="com.github.pagehelper.PageInterceptor"></bean>
            </array>
        </property>
    </bean>
    <!-- by dao The interface under the package generates a proxy implementation class -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.gjx.dao"/>
    </bean>
</beans>

（4） To configure web.xml

<?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">
    <!-- To configure DispatcherServlet-->
    <servlet>
        <servlet-name>DispatcherServlet</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>
        <!--tomcat Create at startup DispatcherServlet  The default is to create -->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

（5）mybatis Code generator code

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <!-- Add a connection to the database jar The location of the package , At the bottom left of the project external libraries Copy full path found in -->
    <classPathEntry location="E:\repMaven\mysql\mysql-connector-java\8.0.29\mysql-connector-java-8.0.29.jar" />

    <!--
       targetRuntime  :MyBatis3  Generate   exmple
                       MyBatis3Simple    No generation exmple
     -->
    <context id="DB2Tables" targetRuntime="MyBatis3Simple">
        <!--  Remove automatically generated comments or not  true： yes  ： false: no  -->
        <commentGenerator>
            <property name="suppressAllComments" value="true" />
        </commentGenerator>
        <!-- Database connection information ： Drive class 、 Connection address 、 user name 、 password  -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/vue01?serverTimezone=Asia/Shanghai"
                        userId="root"
                        password="990412">
            <!-- solve mysql8.0 The problem of generating all tables repeatedly in the future -->
            <property name="nullCatalogMeansCurrent" value="true" />
        </jdbcConnection>

        <!--  Default false, hold JDBC DECIMAL(decimal)  and  NUMERIC(numeric)  Type resolution as  Integer, by  true When the JDBC DECIMAL  and 
            NUMERIC  Type resolution as java.math.BigDecimal -->
        <javaTypeResolver >
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- Configuration of entity class , targetProject: Where to generate entity classes  -->
        <javaModelGenerator targetPackage="com.gjx.entity" targetProject=".\src\main\java">
            <!-- enableSubPackages: Whether to let schema As the suffix of the package  -->
            <property name="enableSubPackages" value="false" />
            <!--  The value returned from the database is cleared before and after the space  -->
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!-- The mapping file mapper Configuration of -->
        <sqlMapGenerator targetPackage="mapper"  targetProject=".\src\main\resources">
            <property name="enableSubPackages" value="false" />
        </sqlMapGenerator>

        <!--dao Package is the configuration of business logic layer -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.gjx.dao"  targetProject=".\src\main\java">
            <property name="enableSubPackages" value="false" />
        </javaClientGenerator>

        <!--
         Configuration of database tables 
        -->
        <table schema="" tableName="tbl_user" domainObjectName="User">

        </table>

        <table schema="" tableName="t_stu" domainObjectName="Stu">

        </table>

        <table schema="" tableName="t_teacher" domainObjectName="Teacher">

        </table>

    </context>
</generatorConfiguration>

（6） Run the code generator

public class Run {
    @Test
    public void run() throws Exception {
        List<String> warnings = new ArrayList<String>();
        boolean overwrite = true;
        File configFile = new File("mybatis-generator.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、SSM Framework directory structure