一文搞懂SSM的搭建及运行流程

Others 2021-11-17 18:28:24 views: null
  • 创建maven项目

在这里插入图片描述

  • 引入依赖
 <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.9</version>
    </dependency>


<!--    spring mvc相关-->

<!--WebApplicationContextUtils-->
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>5.3.9</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.9</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>5.3.9</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.9.7</version>
      <scope>runtime</scope>
    </dependency>


    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>


    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.3.9</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.12.3</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.12.4</version>
    </dependency>


<!--    mybatis相关-->
    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.37</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.6</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>2.0.5</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.16</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.2.6</version>
    </dependency>
  • springmvc的配置文件
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

<!--    只扫描controller-->
    <context:component-scan base-package="com.ssm.crud">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>


<!--    注解驱动 -->
    <mvc:annotation-driven/>


<!--    静态资源的处理-->
    <mvc:default-servlet-handler/>


<!--    视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>


<!--    <mvc:interceptors>-->
<!--        <mvc:interceptor>-->
<!--            <mvc:mapping path="/**"/>-->
<!--            <mvc:exclude-mapping path="/admin/**"/>-->
<!--            <bean class="com.ssm.crud.bean.User"></bean>-->
<!--        </mvc:interceptor>-->
<!--    </mvc:interceptors>-->

</beans>
  • spring配置文件
<?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"
       xmlns:aop="http://www.springframework.org/schema/aop"
       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 http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">

    <context:component-scan base-package="com.ssm.crud">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

<!--    配置数据源-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="password" value="root"></property>
        <property name="username" value="root"></property>
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://47.93.56.27:3306/ssm"></property>
    </bean>

<!--    配置mybatis与spring的整合，也就是当我们在service层自动注入Mapper时，
此时的Mapper不是spring创建的，而是mybatis创建的 所以要让mybaits创建好mapper实现以后，自动
放入spring的IOC容器中-->
<!--    这个bean负责扫描mapper接口与其绑定的xml文件，创建代理对象，但是
要想创建代理对象，还需要sqlSessionFactroy这个类，所以这个类也需要放入spring容器中-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.ssm.crud.mapper"></property>
    </bean>

    <bean class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
        <property name="configLocation" value="classpath:mybatisConfig.xml"></property>
        <property name="mapperLocations" value="classpath:mapper/*.xml"></property>
    </bean>


<!--    spring声明式事务-->
<!--    1.配置事务管理器-->
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <property name="dataSource" ref="dataSource"></property>
        </bean>

<!--    配置通知（增强），一般的增强都是我们自己写的，不需要配置，只需要配置织入就可以
        但这个事务通知，我们可以配置一些属性，比如事务传播行为，回滚异常等-->
        <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                <tx:method name="*"/>
                <tx:method name="get*" read-only="true"/>
                <tx:method name="list*" read-only="true"/>
            </tx:attributes>
        </tx:advice>

<!--    配置织入，哪些方法需要哪个通知-->
<!--    <aop:config>-->
<!--        <aop:advisor advice-ref="txAdvice" pointcut="execution(* com.ssm.crud.service..*.*(..))"></aop:advisor>-->
<!--    </aop:config>-->

<!--    相当于springboot的 @EnableTranstionManagment-->
    <tx:annotation-driven transaction-manager="transactionManager"/>

</beans>
  • mybatis的Mapper文件
<?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.ssm.crud.mapper.UserMapper">


    <insert id="save">

        insert into user(`name`,age)values (#{name},#{age})

    </insert>
    <select id="list" resultType="user">
        select * from user
    </select>
</mapper>
  • web.xml文件
<?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">

<!--    配置spring的监听器，项目一启动，创建IOC容器，注入好依赖关系，并且将
    IOC容器放入ServletContext中-->

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <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:spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>DispatcherServlet</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>forceRequestEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>
  • 普通Javaweb工程与SSM工程对比。
    SSM就是在Javaweb工程上进一步的封装，之前都是在web.xml中配置好，每一个Servlet对应的请求，当服务器接收到请求时，tomcat创建Servlet对象并执行doGet或doPost方法，此时Servlet再调用Service方法，Service层再调用Dao层方法将数据保存到数据库中。
    当用了SSM以后，我们就只需要在web.xml配置少量信息就可以运行项目。spring监听器的作用就是当服务器启动时，加载配置文件，通过反射创建对象，并解决好属性依赖，也就是不需要在Servlet中new xxxService(),Service中也不需要在new xxxDao。这就实现了控制反转。然后再就是springmvc的DispatcherServlet，这个servlet拦截所有请求，当服务器接收到请求以后，就交给了这个DispatcherServlet处理， 在这个servlet中，springmvc会根据请求的url等信息，找到所有的controller，再找到每个controller中标注了@RequestMapping的方法，还是通过反射，来执行处理器方法，执行完成以后，由springmvc返回给前端。这里涉及到一个问题，就是Springmvc在创建controller对象时，如果自动注入了service，然后service是在spring的容器中的，springmvc是怎么找到的？因为spring的监听器在创建完IOC容器中后，会将容器拷贝到servletContext中，通过spring提供的WebApplicationContextUtils可以获取spring的容器中的对象，此时springmvc就可以完成依赖注入。spring又是怎么和mybatis整合的？此时我们引入了spring和mybatis的适配包，让spring创建mybatis的SqlSessionFactionBean，还要告诉mybatis的代理接口在哪里，让spring创建MapperScannerConfirue对象，执行接口包，这个对象会从容器中拿到SqlSessionFactory，然后为每一个接口创建代理对象，放入spring容器中，此时就可以在service层自动注入mybatis的接口实现对象了。

Guess you like

Origin blog.csdn.net/qq_43750656/article/details/120629701
Recommended
Rushing to the GitHub hot list——How can open source programming languages and frameworks be so cute?
Beijing Humanoid Robot Innovation Center launches Tiangong, the world's first full-size humanoid robot with purely electric drive for anthropomorphic running
Ranking
8个无需编写代码即可使用 Python 内置库的方法
Java collections interview knowledge Lite
Machine learning algorithms foundation - Introduction a (watermelon materials for the book)
(Easy) Ransom Note - LeetCode
[Five days] Qt from entry to actual combat: the second day
Remember once extremely pit father can not download Maven Jar package of issues: IDEA question
The minimum cost Shortest
OSPF study map (the most complete version)
Network Takeaways
GnuPG
Daily
More
2024-04-27(29)
2024-04-26(22)
2024-04-25(32)
2024-04-24(30)
2024-04-23(30)
2024-04-22(5)
2024-04-21(0)
2024-04-20(6)
2024-04-19(5)
2024-04-18(0)

Code World

© 2018 codetd.com