Create project and SSM framework integration ideas

One, create a project

Because springMVC will be configured later, create a maven project with IDEA's web skeleton.

image

Create the project directory as follows. At the same time, the packages and files required by the project have been manually created:

image

In the above figure, application.xml is the spring configuration file, log4j is the log configuration file, and springMVC.xml is the springMVC configuration file

Configure the required dependencies in the pom.xml file. The dependencies of the entire project are as follows.

<?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.hust.demo-ssm</groupId>
  <artifactId>demo</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>demo Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <spring.version>5.0.2.RELEASE</spring.version>
    <slf4j.version>1.6.6</slf4j.version>
    <log4j.version>1.2.12</log4j.version>
    <mysql.version>5.1.6</mysql.version>
    <mybatis.version>3.4.5</mybatis.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.6.8</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>compile</scope>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <!-- log start -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>${log4j.version}</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>${slf4j.version}</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>${slf4j.version}</version>
    </dependency>

    <!-- log end -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>

    <dependency>
      <groupId>c3p0</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.1.2</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.0</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.9.0</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>2.9.0</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>demo</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

</pre>

So at this time, the skeleton of the project has been built, and the dependencies of the project have been imported, and then I will introduce the idea of integration.

2. SSM integration ideas

In terms of purpose, after integration, the service layer must be able to call methods of the dao layer through dependency injection, and the controller layer must call methods of the service layer through dependency injection. Therefore, the basic idea of integration is to use spring to integrate mybatis and springMVC.

image

Mybatis configuration

First, we first configure the mybatis framework.

One, create the database demo_ssm and create the account table

The sql statement is as follows:

CREATE DATABASE `demo_ssm`;
USE `demo_ssm`;
DROP TABLE IF EXISTS `account`;
CREATE TABLE `account`(
    `id` INT(11) NOT NULL AUTO_INCREMENT,
    `name` VARCHAR(32),
    `money` DOUBLE,
    PRIMARY KEY(`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO `account`(`name`,`money`) VALUES('赵敏',99999.99),('张无忌',11111.1),('木婉清',22222.22);

</pre>

2. Create an account entity class:

public class Account implements Serializable {
    private Integer id;
    private String name;
    private Double money;
 //getter and setter
 //toString
}

</pre>

Third, use annotations to develop the persistence layer interface

package com.hust.dao;

public interface IAccountDao {

    @Select("select * from account")
    public List<Account> findAllAccount();
}

</pre>

At this point, Mybatis is configured. At this time, the data source has not been configured. We will wait to configure and test when integrating Spring.

Spring configuration and integration of Mybatis

One, Spring configuration

At this time applicationContext.xml file configuration:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
       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.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <!--    配置扫描-->
    <context:component-scan base-package="com.hust">
        <context:exclude-filter type="annotation"  expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>
</beans>

</pre>

important point:

Automatic assembly needs to scan the annotations in the package, so it is necessary to configure to enable annotation scanning. There are two ways to enable annotation scanning, namely <context:annotation-config/> and <context:component-scan>. The similarities and differences between the two are as follows:

<context:annotation-config>: Annotation scanning is for beans that have been registered in the Spring container

<context:component-scan>: Not only has all the functions of <context:annotation-config>, but also scans the corresponding bean under the specified package

Two, Spring integrates Mybatis

Thinking analysis:

The Mybatis framework can automatically generate a proxy object. Therefore, for the persistence layer, we only wrote an interface and annotations. The specific implementation class is completed by the framework for us. The CRUD of the database is also implemented through this proxy object. Therefore, as long as we can store the generated proxy object in the container and let the Spring framework control it, then the integration will be successful.

Another key point is that the Mybatis framework uses SqlSessionFactory factory instances to create SqlSession instances. Through SqlSession instances, we can operate the database.

In short, the key to Spring integration with Mybatis is to allow the container to control the SqlSessionFactoryBean class.

Specific placement

The specific configuration is divided into three parts:

1. Configure connection **** pool **** 2. Configure sqlSession factory class 3. Configure scanner for scanning package

So the configuration is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
       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.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <!--    配置扫描-->
    <context:component-scan base-package="com.hust">
    </context:component-scan>

    <!--    配置数据源-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql:///demo_ssm"/>
        <property name="user" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <!--    配置SqlSession的工厂-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <!--  配置扫描的包  -->
    <bean id="mapperScanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.hust.dao"/>
    </bean>
</beans>

</pre>

After this configuration, the Spring container can create the sqlSession factory class. Then add the @Repository annotation to IAccountDao, then the proxy object of the AccountDao interface can be managed by the container and integrated. Let's test it with the test class:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:applicationContext.xml"})
public class SpringTest {

    @Autowired
    private IAccountDao accountDao;

    @Test
    public void testSpring(){
        List<Account> accounts = accountDao.findAllAccount();
        for (Account account:accounts
             ) {
            System.out.println(account);
        }
    }
}

</pre>

The results are as follows:

Account{id=1, name='赵敏', money=99999.99}
Account{id=2, name='张无忌', money=11111.1}
Account{id=3, name='木婉清', money=22222.22}

</pre>

All accounts have been successfully queried, indicating that dependency injection can be achieved through the container, which indicates that both spring and mybatis are successfully configured and integrated successfully.

PS: Here Spring uses @RunWith and @ContextConfiguration to integrate junit

springMVC configuration

1. Configure web.xml

The SpringMVC framework is designed around DispatcherServlet, which is used to process all HTTP requests and responses. So we need to configure the web.xml file to map the requests that we want DispatcherServlet to handle.

<servlet>
    <servlet-name>demo</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>demo</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

</pre>

Obviously you need to configure the servlet and servlet mapping.

The <init-param> configuration allows us to load the servlet configuration file during initialization.

2. Place spring MVC.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd">
    <!-- 配置创建 springMVC要扫描的包 -->
    <context:component-scan base-package="com.hust">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!-- 开启SpringMVC框架注解的支持 -->
    <mvc:annotation-driven/>
</beans>

</pre>

3. Write AccountController class

@Controller
@RequestMapping("/account")
public class AccountController {
    @Autowired
    private IAccountService accountService;

    @RequestMapping("/all")
    public String findAllAccounts(){
        return "success";
    }
}

</pre>

At this point, springMVC has been configured, we start the server, and when we jump to the success.jsp page after accessing the /account/all path, the following picture appears.

image

It shows that the springMVC configuration is successful

Spring integrates springMVC

Thinking analysis

If the server is started at this time, the applicationContext.xml file is not loaded, and the spring framework does not play a role, so it is impossible to implement dependency injection through the @AutoWire annotation and call the method of the service layer. Therefore, our idea is to load the configuration file and create the container when the server starts. In this way, the presentation layer can call the business layer methods.

Implementation

We set the listener so that after the server starts, the configuration file will be loaded and the container will be initialized.

The final web.xml file is as follows:

<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
    <display-name>Archetype Created Web Application</display-name>

    <!-- 配置spring提供的监听器，用于启动服务时加载容器。
    该监听器会加载WEB-INF目录中名称为applicationContext.xml的配置文件-->
    <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
    </listener>

    <!-- 指定spring配置文件的位置 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

    <servlet>
        <servlet-name>demo</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>demo</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

</pre>

At the same time, modify the AccountController class

@Controller
@RequestMapping("/account")
public class AccountController {
    @Autowired
    private IAccountService accountService;

    @RequestMapping("/all")
    public String findAllAccounts(){
        List<Account> all = accountService.findAllAccount();
        for (Account a:all
             ) {
            System.out.println(a);
        }
        return "success";
    }
}

</pre>

When accessing the success.jsp page, the backend will output

Account{id=1, name='赵敏', money=99999.99}
Account{id=2, name='张无忌', money=11111.1}
Account{id=3, name='木婉清', money=22222.22}

</pre>

It shows that the accountService object can be injected through the container, and the integration is successful.

PS: Use the @RestController annotation to realize the api to achieve the effect of separating the front and back ends.

summary

The key point is mainly how to use the spring framework to integrate other frameworks. Among them, the understanding of the role of the spring framework is very important!

If you have any questions or write something wrong, please leave a message to discuss!

Different ideas, this is the most concise and clear SSM framework integration I have seen

Create project and SSM framework integration ideas

Mybatis configuration

Spring configuration and integration of Mybatis

Two, Spring integrates Mybatis

springMVC configuration

Spring integrates springMVC

summary

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