SSM 整合

SSM 概念

在项目中:

  • SpringMVC 框架负责控制层
  • Spring 框架负责整体和业务层的声明式事务管理
  • MyBatis 框架负责数据库访问层

实施:通过编写配置文件,实现 SpringIoC 容器接管一切组件

本质上说,整合就是将三层架构和框架核心API组件交给SpringIoC容器管理

一个容器可能就够了,但是我们常见的操作是创建两个IoC容器(web容器和root容器),组件分类管理

总结:

容器名 盛放组件
web容器 web相关组件(controller,springmvc 核心组件)
root容器 业务和持久层相关组件(service,aop,tx,dataSource,mybatis,mapper 等)

整合实战

导入依赖

需要依赖清单分析:

  • spring
    • ioc/di: spring-context ,jakarta.annotation-api
    • aop:spring-aspects
    • tx:spring-tx,spring-tx
  • springmvc
    • spring-webmvc
    • jakarta.jakartaee-web-api
    • jackson-databind
    • hibernate-validator / hibernate-validator-annotation-processor 8.0.0.Final
  • mybatis
    • mybatis
    • mysql
    • pagehelper
  • 其他整合需要
    • spring-web
    • mybatis-spring
    • druid
    • lombok
    • logback
<!-- 打包方法改成 war   -->
<packaging>war</packaging>
<properties>
  <!-- 声明版本号    -->
  <spring.version>6.0.6</spring.version>
  <jakarta.annotation-api.version>2.1.1</jakarta.annotation-api.version>
  <jakarta.jakartaee-web-api.version>9.1.0</jakarta.jakartaee-web-api.version>
  <jackson-databind.version>2.15.0</jackson-databind.version>
  <hibernate-validator.version>8.0.0.Final</hibernate-validator.version>
  <mybatis.version>3.5.11</mybatis.version>
  <mysql.version>8.0.25</mysql.version>
  <pagehelper.version>5.1.11</pagehelper.version>
  <druid.version>1.2.8</druid.version>
  <mybatis-spring.version>3.0.2</mybatis-spring.version>
  <jakarta.servlet.jsp.jstl-api.version>3.0.0</jakarta.servlet.jsp.jstl-api.version>
  <logback.version>1.2.3</logback.version>
  <lombok.version>1.18.26</lombok.version>
  <maven.compiler.source>17</maven.compiler.source>
  <maven.compiler.target>17</maven.compiler.target>  
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 
</properties>

<dependencies>
  <!--spring pom.xml依赖-->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>jakarta.annotation</groupId>
    <artifactId>jakarta.annotation-api</artifactId>
    <version>${jakarta.annotation-api.version}</version>
  </dependency>

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

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</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>${spring.version}</version>
  </dependency>
  <!--
       springmvc
           spring-webmvc 6.0.6
           jakarta.jakartaee-web-api 9.1.0
           jackson-databind 2.15.0
           hibernate-validator / hibernate-validator-annotation-processor 8.0.0.Final
    -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>jakarta.platform</groupId>
    <artifactId>jakarta.jakartaee-web-api</artifactId>
    <version>${jakarta.jakartaee-web-api.version}</version>
    <scope>provided</scope>
  </dependency>

  <!-- jsp需要依赖! jstl-->
  <dependency>
    <groupId>jakarta.servlet.jsp.jstl</groupId>
    <artifactId>jakarta.servlet.jsp.jstl-api</artifactId>
    <version>${jakarta.servlet.jsp.jstl-api.version}</version>
  </dependency>

  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>${jackson-databind.version}</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.hibernate.validator/hibernate-validator -->
  <dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>${hibernate-validator.version}</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.hibernate.validator/hibernate-validator-annotation-processor -->
  <dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator-annotation-processor</artifactId>
    <version>${hibernate-validator.version}</version>
  </dependency>
  <!--
      mybatis
           mybatis  / 3.5.11
           mysql    / 8.0.25
           pagehelper / 5.1.11
    -->
  <!-- mybatis依赖 -->
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>${mybatis.version}</version>
  </dependency>

  <!-- MySQL驱动 mybatis底层依赖jdbc驱动实现,本次不需要导入连接池,mybatis自带! -->
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>${mysql.version}</version>
  </dependency>

  <dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper</artifactId>
    <version>${pagehelper.version}</version>
  </dependency>

  <!-- 整合第三方特殊依赖 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>${spring.version}</version>
  </dependency>

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

  <!-- 日志 , 会自动传递slf4j门面-->
  <dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>${logback.version}</version>
  </dependency>

  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>${lombok.version}</version>
  </dependency>

  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>${druid.version}</version>
  </dependency>

</dependencies>

创建数据库

CREATE DATABASE `ssm`;

USE `ssm`;

CREATE TABLE `t_emp`(
  emp_id INT AUTO_INCREMENT,
  emp_name CHAR(100),
  emp_salary DOUBLE(10,5),
  PRIMARY KEY(emp_id)
);

INSERT INTO `t_emp`(emp_name,emp_salary) VALUES("tom",200.33);
INSERT INTO `t_emp`(emp_name,emp_salary) VALUES("jerry",666.66);
INSERT INTO `t_emp`(emp_name,emp_salary) VALUES("andy",777.77);

创建实体类

位置:com.ssm.pojo

@Data
public class Employee {
    private Integer empId;
    private String empName;
    private Double empSalary;
}

配置日志

位置:resources/logback.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration debug="true">
  <!-- 指定日志输出的位置,ConsoleAppender表示输出到控制台 -->
  <appender name="STDOUT"
            class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <!-- 日志输出的格式 -->
      <!-- 按照顺序分别是:时间、日志级别、线程名称、打印日志的类、日志主体内容、换行 -->
      <pattern>[%d{HH:mm:ss.SSS}] [%-5level] [%thread] [%logger] [%msg]%n</pattern>
      <charset>UTF-8</charset>
    </encoder>
  </appender>

  <!-- 设置全局日志级别。日志级别按顺序分别是:TRACE、DEBUG、INFO、WARN、ERROR -->
  <!-- 指定任何一个日志级别都只打印当前级别和后面级别的日志。 -->
  <root level="DEBUG">
    <!-- 指定打印日志的appender,这里通过“STDOUT”引用了前面配置的appender -->
    <appender-ref ref="STDOUT" />
  </root>

  <!-- 根据特殊需求指定局部日志级别,可也是包名或全类名。 -->
  <logger name="com.ssm.mybatis" level="DEBUG" />

</configuration>

配置 SpringMVC 控制层

创建配置文件:WebJavaConfig.java (命名随意)

/**
 * 1.实现Springmvc组件声明标准化接口WebMvcConfigurer 提供了各种组件对应的方法
 * 2.添加配置类注解@Configuration
 * 3.添加mvc复合功能开关@EnableWebMvc
 * 4.添加controller层扫描注解
 * 5.开启默认处理器,支持静态资源处理
 */
@Configuration
@EnableWebMvc
@ComponentScan("com.ssm.controller")
public class WebJavaConfig implements WebMvcConfigurer {

  //开启静态资源
  @Override
  public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    configurer.enable(); 
  }
}

配置业务层

配置 AOP 切面 / TX 声明事务整合:ServiceJavaConfig.java (命名随意)

/**
 * 1. 声明@Configuration注解,代表配置类
 * 2. 声明@EnableTransactionManagement注解,开启事务注解支持
 * 3. 声明@EnableAspectJAutoProxy注解,开启aspect aop注解支持
 * 4. 声明@ComponentScan("com.ssm.service")注解,进行业务组件扫描
 * 5. 声明transactionManager(DataSource dataSource)方法,指定具体的事务管理器
 */
@EnableTransactionManagement
@EnableAspectJAutoProxy
@Configuration
@ComponentScan("com.ssm.service")
public class ServiceJavaConfig {
    
    @Bean
    public DataSourceTransactionManager transactionManager(DataSource dataSource){
        DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
        transactionManager.setDataSource(dataSource);
        return transactionManager;
    }
    
}

配置持久层

整合 mybatis 配置mapper代理对象,连接池和mybatis核心组件配置

mybatis整合思路:

  • 需要将 SqlSessionFactory 和 Mapper 实例加入到IoC容器
  • 使用 mybatis 整合包提供的 FactoryBean 快速整合

创建数据库连接信息配置

位置:resources/jdbc.properties

jdbc.user=root
jdbc.password=123456
jdbc.url=jdbc:mysql:///ssm
jdbc.driver=com.mysql.cj.jdbc.Driver

数据库配置类

@Configuration
@PropertySource("classpath:jdbc.properties")
public class DataSourceJavaConfig {
  @Value("${jdbc.user}")
  private String user;
  @Value("${jdbc.password}")
  private String password;
  @Value("${jdbc.url}")
  private String url;
  @Value("${jdbc.driver}")
  private String driver;
  //数据库连接池配置
  @Bean
  public DataSource dataSource(){
    DruidDataSource dataSource = new DruidDataSource();
    dataSource.setUsername(user);
    dataSource.setPassword(password);
    dataSource.setUrl(url);
    dataSource.setDriverClassName(driver);
    return dataSource;
  }
}

整合 mybatis中 xml 和配置类整合二选一

结合 xml 配置整合

创建 mybatis 配置文件

位置:resources/mybatis-config.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>
  <settings>
    <!-- 开启驼峰式映射-->
    <setting name="mapUnderscoreToCamelCase" value="true"/>
    <!-- 开启logback日志输出-->
    <setting name="logImpl" value="SLF4J"/>
    <!--开启resultMap自动映射 -->
    <setting name="autoMappingBehavior" value="FULL"/>
  </settings>

  <typeAliases>
    <!-- 给实体类起别名 -->
    <package name="com.ssm.pojo"/>
  </typeAliases>

  <plugins>
    <plugin interceptor="com.github.pagehelper.PageInterceptor">

      <!--
				helperDialect:分页插件会自动检测当前的数据库链接,自动选择合适的分页方式
				你可以配置 helperDialect 属性来指定分页插件使用哪种方言
       -->
      <property name="helperDialect" value="mysql"/>
    </plugin>
  </plugins>
</configuration>

mybatis 配置类

@Configuration
public class MapperJavaConfig {
  /**
  * 配置SqlSessionFactoryBean,指定连接池对象和外部配置文件即可
  * @param dataSource 需要注入连接池对象
  * @return 工厂Bean
  */
  @Bean
  public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource){
    //实例化SqlSessionFactory工厂
    SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();

    //设置连接池
    sqlSessionFactoryBean.setDataSource(dataSource);

    //设置配置文件
    //包裹外部配置文件地址对象
    Resource resource = new ClassPathResource("mybatis-config.xml");
    sqlSessionFactoryBean.setConfigLocation(resource);

    return sqlSessionFactoryBean;
  }

  /**
  * 配置Mapper实例扫描工厂,配置 <mapper <package 对应接口和mapperxml文件所在的包
  */
  @Bean
  public MapperScannerConfigurer mapperScannerConfigurer(){
    MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
    //设置mapper接口和xml文件所在的共同包
    mapperScannerConfigurer.setBasePackage("com.ssm.mapper");
    return mapperScannerConfigurer;
  }

}

注意:数据库和 mybatis 要分成两个配置类独立配置,互不影响,数据库提取一个配置类,mybatis提取一个配置类

原因:当你在Spring配置类中添加了sqlSessionFactoryBeanmapperScannerConfigurer配置方法时,可能会导致@Value注解读取不到值为null的问题

这是因为SqlSessionFactoryBeanMapperScannerConfigurer是基于MyBatis框架的配置,它们的初始化顺序可能会导致属性注入的问题

结合配置类整合

不在保留mybatis的外部配置文件(xml), 所有配置信息(settings、插件、别名等)全部在声明SqlSessionFactoryBean的代码中指定!数据库信息依然使用DruidDataSource实例替代

mapper 配置类

// description: 持久层配置和Druid和Mybatis配置 使用一个配置文件
@Configuration
public class MapperJavaConfigNew {

  /**
     * 配置SqlSessionFactoryBean,指定连接池对象和外部配置文件即可
     * @param dataSource 需要注入连接池对象
     * @return 工厂Bean
     */
  @Bean
  public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource){
    //实例化SqlSessionFactory工厂
    SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();

    //设置连接池
    sqlSessionFactoryBean.setDataSource(dataSource);

    
    //settings [包裹到一个configuration对象,切记别导错包]
    org.apache.ibatis.session.Configuration configuration = 
      new org.apache.ibatis.session.Configuration();
    configuration.setMapUnderscoreToCamelCase(true);
    configuration.setLogImpl(Slf4jImpl.class);
    configuration.setAutoMappingBehavior(AutoMappingBehavior.FULL);
    sqlSessionFactoryBean.setConfiguration(configuration);

    //typeAliases
    sqlSessionFactoryBean.setTypeAliasesPackage("com.ssm.pojo");

    //分页插件配置
    PageInterceptor pageInterceptor = new PageInterceptor();

    Properties properties = new Properties();
    properties.setProperty("helperDialect","mysql");
    pageInterceptor.setProperties(properties);
    sqlSessionFactoryBean.addPlugins(pageInterceptor);

    return sqlSessionFactoryBean;
  }

  /**
     * 配置Mapper实例扫描工厂,配置 <mapper <package 对应接口和mapperxml文件所在的包
     */
  @Bean
  public MapperScannerConfigurer mapperScannerConfigurer(){
    MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
    //设置mapper接口和xml文件所在的共同包
    mapperScannerConfigurer.setBasePackage("com.ssm.mapper");
    return mapperScannerConfigurer;
  }

}

容器初始化

配置名 对应内容 对应容器
WebJavaConfig controller,springmvc相关 web容器
ServiceJavaConfig service,aop,tx相关 root容器
MapperJavaConfig mapper,datasource,mybatis相关 root容器
public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

  //指定root容器对应的配置类
  @Override
  protected Class<?>[] getRootConfigClasses() {
    return new Class<?>[] {MapperJavaConfig.class, ServiceJavaConfig.class, DataSourceJavaConfig.class };
  }

  //指定web容器对应的配置类
  @Override
  protected Class<?>[] getServletConfigClasses() {
    return new Class<?>[] { WebJavaConfig.class };
  }

  //指定dispatcherServlet处理路径,通常为 / 
  @Override
  protected String[] getServletMappings() {
    return new String[] { "/" };
  }
}

简单测试

查询所有员工信息,返回对应json数据!

controller

@Slf4j
@RestController
@RequestMapping("/employee")
public class EmployeeController {

  @Autowired
  private EmployeeService employeeService;

  @GetMapping("list")
  public List<Employee> retList(){
    List<Employee> employees = employeeService.findAll();
    log.info("员工数据:{}",employees);
    return employees;
  }
}

service

接口

public interface EmployeeService {
    List<Employee> findAll();
}

实现类

@Service
public class EmployeeServiceImpl implements EmployeeService {

  @Autowired
  private EmployeeMapper employeeMapper;

  /**
     * 查询所有员工信息
     */
  @Override
  public List<Employee> findAll() {
    List<Employee> employeeList =  employeeMapper.queryAll();
    return employeeList;
  }
}

mapper

mapper 接口类

位置:com.ssm.mapper

public interface EmployeeMapper {

  List<Employee> queryAll();
}

mapper xml 配置文件

位置:resources/com/ssm/mapper

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ssm.mapper.EmployeeMapper">
  <select id="queryAll" resultType="employee">
    select emp_id empId,emp_name empName, emp_salary empSalary from t_emp
  </select>
</mapper>


参考资料