【Mybatis】springboot+mybatis,全局配置加载

素颜马尾好姑娘i 2022-11-27 01:53 182阅读 0赞

### 目录 ###

*  一、项目搭建
 *   *  1.1、项目结构
     *  1.2、pom.xml
     *  1.3、application.properties
     *  1.4、SQL脚本
 *  二、全局配置加载
 *   *  2.1 MybatisAutoConfiguration
     *  2.2 SqlSessionFactoryBean
     *   *  2.2.1 afterPropertiesSet 方法
         *  2.2.2 buildSqlSessionFactory
     *  2.3 SqlSessionFactoryBuilder
     *   *  2.3.1 build 构建SqlSessionFactory
     *  2.4 DefaultSqlSessionFactory
     *   *  2.4.1 build 构建 SqlSessionFactory
 *  三、总结 & 问题
 *   *  3.1 问题汇总
     *   *  3.1.1:FactoryBean和BeanFactory有什么区别？
         *  3.1.2:afterPropertiesSet在什么时候执行？需要实现哪个类？
         *  3.1.3:SqlSessionFactory、SqlSessionFactoryBuilder用了哪些设计模式？这些设计模式有什么优缺点？
     *  3.2 总结
     *   *  3.2.1 用到的jar
         *  3.2.2 用到的类
         *  3.2.3 用到的方法
 *  四、mapper的xml文件解析流程

# 一、项目搭建 #

> 由于本项目只是为了阅读mybatis源码使用，就没有用分层架构。  
> 现在是表现层、业务层、持久层都在一个项目里面。  
> ***由于一个人的视角，可能存在纰漏和错误，欢迎大家指正！***

## 1.1、项目结构 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aG9uZ2xlaTE5ODc_size_16_color_FFFFFF_t_70_pic_center]

## 1.2、pom.xml ##

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <groupId>com.lhl.dockerfile</groupId>
        <artifactId>springboot-dockerfile</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>springboot-dockerfile</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.3.0.RELEASE</version>
        </parent>
    
        <properties>
            <java.version>1.8</java.version>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <spring-boot.version>2.3.0.RELEASE</spring-boot.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
                <version>${spring-boot.version}</version>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.12</version>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <version>${spring-boot.version}</version>
                <scope>test</scope>
                <exclusions>
                    <exclusion>
                        <groupId>org.junit.vintage</groupId>
                        <artifactId>junit-vintage-engine</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.13</version>
                <scope>test</scope>
            </dependency>
    
            <dependency>
                <groupId>com.squareup.okhttp3</groupId>
                <artifactId>okhttp</artifactId>
                <version>4.2.2</version>
            </dependency>
            
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.15</version>
            </dependency>
            
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>1.1.21</version>
            </dependency>
    
    
        </dependencies>
    
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                        <encoding>UTF-8</encoding>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <executions>
                        <execution>
                            <goals>
                                <goal>repackage</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </build>
    
    </project>

## 1.3、application.properties ##

spring.application.name=springboot-dockerfile
    management.endpoints.jmx.exposure.include=*
    management.endpoints.web.exposure.include=*
    management.endpoint.health.show-details=always
    # spring cloud access&secret config
    # 可以访问如下地址查看: https://usercenter.console.aliyun.com/#/manage/ak
    alibaba.cloud.access-key=****
    alibaba.cloud.secret-key=****
    # 应用服务 WEB 访问端口
    server.port=8080
    # Actuator Web 访问端口
    management.server.port=8081
    
    # dataSource
    spring.datasource.url=jdbc:mysql://127.0.0.1:3306/all_account?useUnicode=true&characterEncoding=utf-8
    spring.datasource.username=root
    spring.datasource.password=
    spring.datasource.druid.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.druid.initialSize=10
    spring.datasource.druid.maxActive=20
    spring.datasource.druid.maxWait=60000
    spring.datasource.druid.minIdle=1
    spring.datasource.druid.timeBetweenEvictionRunsMillis=60000
    spring.datasource.druid.minEvictableIdleTimeMillis=300000
    spring.datasource.druid.testWhileIdle=true
    spring.datasource.druid.testOnBorrow=true
    spring.datasource.druid.testOnReturn=false
    spring.datasource.druid.poolPreparedStatements=true
    spring.datasource.druid.maxOpenPreparedStatements=20
    spring.datasource.druid.validationQuery=SELECT 1
    spring.datasource.druid.validation-query-timeout=500
    spring.datasource.druid.filters=stat
    # MyBatis
    mybatis.mapper-locations=classpath*:/mapper/*Mapper.xml
    mybatis.configuration.map-underscore-to-camel-case=true
    mybatis.configuration.default-fetch-size=100
    mybatis.configuration.default-statement-timeout=30
    mybatis.configuration.cache-enabled=false
    mybatis.configuration.lazy-loading-enabled=false
    mybatis.configuration.multiple-result-sets-enabled=false
    mybatis.configuration.use-column-label=true
    mybatis.configuration.use-generated-keys=false
    mybatis.configuration.auto-mapping-behavior=FULL
    mybatis.configuration.default-executor-type=SIMPLE
    mybatis.configuration.safe-row-bounds-enabled=false
    mybatis.configuration.local-cache-scope=SESSION
    mybatis.configuration.jdbc-type-for-null=OTHER
    mybatis.configuration.lazy-load-trigger-methods=equals,clone,hashCode,toString

## 1.4、SQL脚本 ##

SET NAMES utf8;
    SET FOREIGN_KEY_CHECKS = 0;
    
    -- ----------------------------
    -- Table structure for lhl_user
    -- ----------------------------
    DROP TABLE IF EXISTS `lhl_user`;
    CREATE TABLE `lhl_user` (
      `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT COMMENT '主键',
      `name` varchar(255) DEFAULT NULL COMMENT '姓名',
      `age` int(3) DEFAULT NULL COMMENT '年龄',
      PRIMARY KEY (`id`)
    ) DEFAULT CHARSET=utf8 COMMENT='用户表';
    
    SET FOREIGN_KEY_CHECKS = 1;

# 二、全局配置加载 #

> 既然，用的是springboot，那么就要遵循springboot相关规则。

## 2.1 MybatisAutoConfiguration ##

这个类是 **mybatis-spring-boot-autoconfigure:1.3.2**中的文件。

@Bean
    @ConditionalOnMissingBean
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception { 
        SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
        factory.setDataSource(dataSource);
        factory.setVfs(SpringBootVFS.class);
        if (StringUtils.hasText(this.properties.getConfigLocation())) { 
          factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation()));
        }
        Configuration configuration = this.properties.getConfiguration();
        if (configuration == null && !StringUtils.hasText(this.properties.getConfigLocation())) { 
          configuration = new Configuration();
        }
        if (configuration != null && !CollectionUtils.isEmpty(this.configurationCustomizers)) { 
          for (ConfigurationCustomizer customizer : this.configurationCustomizers) { 
            customizer.customize(configuration);
          }
        }
        factory.setConfiguration(configuration);
        if (this.properties.getConfigurationProperties() != null) { 
          factory.setConfigurationProperties(this.properties.getConfigurationProperties());
        }
        if (!ObjectUtils.isEmpty(this.interceptors)) { 
          factory.setPlugins(this.interceptors);
        }
        if (this.databaseIdProvider != null) { 
          factory.setDatabaseIdProvider(this.databaseIdProvider);
        }
        if (StringUtils.hasLength(this.properties.getTypeAliasesPackage())) { 
          factory.setTypeAliasesPackage(this.properties.getTypeAliasesPackage());
        }
        if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) { 
          factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());
        }
        if (!ObjectUtils.isEmpty(this.properties.resolveMapperLocations())) { 
          factory.setMapperLocations(this.properties.resolveMapperLocations());
        }
    
        return factory.getObject();
    }

> 这个类的主要做的就是，加载mysql数据库配置、DataSource配置，并用**SqlSessionFactoryBean**生成**SqlSessionFactory**

## 2.2 SqlSessionFactoryBean ##

> 这个类是 **mybatis-spring:1.3.2** 中的文件

### 2.2.1 afterPropertiesSet 方法 ###

> SqlSessionFactoryBean初始化的时候，执行此方法。

@Override
      public void afterPropertiesSet() throws Exception { 
        notNull(dataSource, "Property 'dataSource' is required");
        notNull(sqlSessionFactoryBuilder, "Property 'sqlSessionFactoryBuilder' is required");
        state((configuration == null && configLocation == null) || !(configuration != null && configLocation != null),
                  "Property 'configuration' and 'configLocation' can not specified with together");
    
        this.sqlSessionFactory = buildSqlSessionFactory();
      }

### 2.2.2 buildSqlSessionFactory ###

> 构建SqlSessionFactory，全局只构建一次

/** * Build a {@code SqlSessionFactory} instance. * * The default implementation uses the standard MyBatis {@code XMLConfigBuilder} API to build a * {@code SqlSessionFactory} instance based on an Reader. * Since 1.3.0, it can be specified a {@link Configuration} instance directly(without config file). * * @return SqlSessionFactory * @throws IOException if loading the config file failed */
    protected SqlSessionFactory buildSqlSessionFactory() throws IOException { 
    
        Configuration configuration;
    
        XMLConfigBuilder xmlConfigBuilder = null;
        if (this.configuration != null) { 
          configuration = this.configuration;
          if (configuration.getVariables() == null) { 
            configuration.setVariables(this.configurationProperties);
          } else if (this.configurationProperties != null) { 
            configuration.getVariables().putAll(this.configurationProperties);
          }
        } else if (this.configLocation != null) { 
          xmlConfigBuilder = new XMLConfigBuilder(this.configLocation.getInputStream(), null, this.configurationProperties);
          configuration = xmlConfigBuilder.getConfiguration();
        } else { 
          if (LOGGER.isDebugEnabled()) { 
            LOGGER.debug("Property 'configuration' or 'configLocation' not specified, using default MyBatis Configuration");
          }
          configuration = new Configuration();
          if (this.configurationProperties != null) { 
            configuration.setVariables(this.configurationProperties);
          }
        }
    
        if (this.objectFactory != null) { 
          configuration.setObjectFactory(this.objectFactory);
        }
    
        if (this.objectWrapperFactory != null) { 
          configuration.setObjectWrapperFactory(this.objectWrapperFactory);
        }
    
        if (this.vfs != null) { 
          configuration.setVfsImpl(this.vfs);
        }
    
        if (hasLength(this.typeAliasesPackage)) { 
          String[] typeAliasPackageArray = tokenizeToStringArray(this.typeAliasesPackage,
              ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
          for (String packageToScan : typeAliasPackageArray) { 
            configuration.getTypeAliasRegistry().registerAliases(packageToScan,
                    typeAliasesSuperType == null ? Object.class : typeAliasesSuperType);
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Scanned package: '" + packageToScan + "' for aliases");
            }
          }
        }
    
        if (!isEmpty(this.typeAliases)) { 
          for (Class<?> typeAlias : this.typeAliases) { 
            configuration.getTypeAliasRegistry().registerAlias(typeAlias);
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Registered type alias: '" + typeAlias + "'");
            }
          }
        }
    
        if (!isEmpty(this.plugins)) { 
          for (Interceptor plugin : this.plugins) { 
            configuration.addInterceptor(plugin);
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Registered plugin: '" + plugin + "'");
            }
          }
        }
    
        if (hasLength(this.typeHandlersPackage)) { 
          String[] typeHandlersPackageArray = tokenizeToStringArray(this.typeHandlersPackage,
              ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
          for (String packageToScan : typeHandlersPackageArray) { 
            configuration.getTypeHandlerRegistry().register(packageToScan);
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Scanned package: '" + packageToScan + "' for type handlers");
            }
          }
        }
    
        if (!isEmpty(this.typeHandlers)) { 
          for (TypeHandler<?> typeHandler : this.typeHandlers) { 
            configuration.getTypeHandlerRegistry().register(typeHandler);
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Registered type handler: '" + typeHandler + "'");
            }
          }
        }
    
        if (this.databaseIdProvider != null) { //fix #64 set databaseId before parse mapper xmls
          try { 
            configuration.setDatabaseId(this.databaseIdProvider.getDatabaseId(this.dataSource));
          } catch (SQLException e) { 
            throw new NestedIOException("Failed getting a databaseId", e);
          }
        }
    
        if (this.cache != null) { 
          configuration.addCache(this.cache);
        }
    
        if (xmlConfigBuilder != null) { 
          try { 
            xmlConfigBuilder.parse();
    
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Parsed configuration file: '" + this.configLocation + "'");
            }
          } catch (Exception ex) { 
            throw new NestedIOException("Failed to parse config resource: " + this.configLocation, ex);
          } finally { 
            ErrorContext.instance().reset();
          }
        }
    
        if (this.transactionFactory == null) { 
          this.transactionFactory = new SpringManagedTransactionFactory();
        }
    
        configuration.setEnvironment(new Environment(this.environment, this.transactionFactory, this.dataSource));
    
        if (!isEmpty(this.mapperLocations)) { 
          for (Resource mapperLocation : this.mapperLocations) { 
            if (mapperLocation == null) { 
              continue;
            }
    
            try { 
              XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(mapperLocation.getInputStream(),
                  configuration, mapperLocation.toString(), configuration.getSqlFragments());
              xmlMapperBuilder.parse();
            } catch (Exception e) { 
              throw new NestedIOException("Failed to parse mapping resource: '" + mapperLocation + "'", e);
            } finally { 
              ErrorContext.instance().reset();
            }
    
            if (LOGGER.isDebugEnabled()) { 
              LOGGER.debug("Parsed mapper file: '" + mapperLocation + "'");
            }
          }
        } else { 
          if (LOGGER.isDebugEnabled()) { 
            LOGGER.debug("Property 'mapperLocations' was not specified or no matching resources found");
          }
        }
    
        return this.sqlSessionFactoryBuilder.build(configuration);
      }

## 2.3 SqlSessionFactoryBuilder ##

> 这个类是 **mybatis:3.4.6** 中的文件

### 2.3.1 build 构建SqlSessionFactory ###

public SqlSessionFactory build(Configuration config) { 
        return new DefaultSqlSessionFactory(config);
      }

## 2.4 DefaultSqlSessionFactory ##

> 这个类是 **mybatis:3.4.6** 中的文件

### 2.4.1 build 构建 SqlSessionFactory ###

public SqlSessionFactory build(Configuration config) { 
        return new DefaultSqlSessionFactory(config);
      }

# 三、总结 & 问题 #

> 项目中使用到了spring、SpringBoot、mybatis框架  
> mybatis框架，可以单独使用，也可以和spring、springboot框架一起使用。  
> 一起使用的时候，spring会把mybatis相关类用jdk动态代理，然后再使用。  
> ***对于，相关问题，大家可以留言回复，互相交流，共同学习进步***

## 3.1 问题汇总 ##

### 3.1.1:FactoryBean和BeanFactory有什么区别？ ###

### 3.1.2:afterPropertiesSet在什么时候执行？需要实现哪个类？ ###

### 3.1.3:SqlSessionFactory、SqlSessionFactoryBuilder用了哪些设计模式？这些设计模式有什么优缺点？ ###

## 3.2 总结 ##

### 3.2.1 用到的jar ###

*  mybatis-spring-boot-autoconfigure:1.3.2
 *  mybatis-spring:1.3.2
 *  mybatis:3.4.6

### 3.2.2 用到的类 ###

*  org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration
 *  org.mybatis.spring.SqlSessionFactoryBean
 *  org.apache.ibatis.session.SqlSessionFactoryBuilder
 *  org.apache.ibatis.session.defaults.DefaultSqlSessionFactory
 *  org.apache.ibatis.session.SqlSessionFactory

### 3.2.3 用到的方法 ###

*  MybatisAutoConfiguration \# sqlSessionFactory(DataSource dataSource) throws Exception
 *  SqlSessionFactoryBean \# getObject() throws Exception
 *  SqlSessionFactoryBean \# afterPropertiesSet() throws Exception
 *  SqlSessionFactoryBean \# buildSqlSessionFactory() throws IOException
 *  SqlSessionFactoryBuilder \# build(Configuration config)
 *  DefaultSqlSessionFactory \# DefaultSqlSessionFactory(Configuration configuration)

# 四、mapper的xml文件解析流程 #

> 下一篇文章，把构建SqlSessionFactory过程中的mapper.xml文件的解析流程写出来。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aG9uZ2xlaTE5ODc_size_16_color_FFFFFF_t_70_pic_center]: /images/20221124/8c8f684ab5264010962487780aac296f.png