• Spring6 (1) IOC

    目录

    1 环境要求

    2 准备工作

    2.1 引入Spring相关依赖

    2.2 Spring配置文件(.xml)

    3 IOC

    3.1 IOC实现

    3.1.1 ApplicationContext的主要实现类

    3.1.3.1 ClassPathXmlApplicationContext

    3.1.3.2 AnnotationConfigApplicationContext

    3.2 依赖注入DI(Dependency Injection)

    3.3 注解开发

    3.3.1 开启组件扫描

    3.3.2 创建对象注解

    3.3.3 依赖注入的注解

    3.3.4 静态依赖注入

    3.4 全注解开发

    1 环境要求

            (1) IDEA开发工具: 2022.3.3

            (2) JDK: Java17+

            (3) Maven: 3.6+

            (4) Spring: 6+

    2 准备工作

    2.1 引入Spring相关依赖

    1. <dependencies>
    2. 	
    3. 	<dependency>
    4. 		<groupId>org.springframeworkgroupId>
    5. 		<artifactId>spring-contextartifactId>
    6. 		<version>${spring-version}version>
    7. 	dependency>
    8.  
    9. 	
    10. 	<dependency>
    11. 		<groupId>org.junit.jupitergroupId>
    12. 		<artifactId>junit-jupiter-apiartifactId>
    13. 		<version>5.10.0version>
    14. 	dependency>
    15.  
    16. 	
    17. 	<dependency>
    18. 		<groupId>org.slf4jgroupId>
    19. 		<artifactId>slf4j-apiartifactId>
    20. 		<version>2.0.9version>
    21. 	dependency>
    22. 	
    23. 	<dependency>
    24. 		<groupId>ch.qos.logbackgroupId>
    25. 		<artifactId>logback-classicartifactId>
    26. 		<version>1.4.11version>
    27. 	dependency>
    28.     
    29.     <dependency>
    30.         <groupId>org.apache.logging.log4jgroupId>
    31.         <artifactId>log4j-coreartifactId>
    32.         <version>2.20.0version>
    33.     dependency>
    34.  
    35. 	
    36. 	<dependency>
    37. 		<groupId>org.springframeworkgroupId>
    38. 		<artifactId>spring-aopartifactId>
    39. 		<version>${spring-version}version>
    40. 	dependency>
    41. 	
    42. 	<dependency>
    43. 		<groupId>org.springframeworkgroupId>
    44. 		<artifactId>spring-aspectsartifactId>
    45. 		<version>${spring-version}version>
    46. 	dependency>
    47.     
    53.  
    54. 	
    60. 	
    61. 	<dependency>
    62. 		<groupId>com.mysqlgroupId>
    63. 		<artifactId>mysql-connector-jartifactId>
    64. 		<version>8.1.0version>
    65. 	dependency>
    66. 	
    67. 	<dependency>
    68. 		<groupId>org.mybatisgroupId>
    69. 		<artifactId>mybatisartifactId>
    70. 		<version>3.5.13version>
    71. 	dependency>
    72. 	
    73. 	<dependency>
    74. 		<groupId>org.mybatisgroupId>
    75. 		<artifactId>mybatis-springartifactId>
    76. 		<version>3.0.2version>
    77. 	dependency>
    78.  
    79. 	
    80. 	<dependency>
    81. 		<groupId>com.alibabagroupId>
    82. 		<artifactId>druidartifactId>
    83. 		<version>1.2.19version>
    84. 	dependency>
    85. 	
    86. 	<dependency>
    87. 		<groupId>com.mchangegroupId>
    88. 		<artifactId>c3p0artifactId>
    89. 		<version>0.9.5.5version>
    90. 	dependency>
    91. 	
    92. 	<dependency>
    93. 		<groupId>org.springframeworkgroupId>
    94. 		<artifactId>spring-jdbcartifactId>
    95. 		<version>${spring-version}version>
    96. 	dependency>
    97. 	
    98. 	<dependency>
    99. 		<groupId>org.springframeworkgroupId>
    100. 		<artifactId>spring-txartifactId>
    101. 		<version>${spring-version}version>
    102. 	dependency>
    103.  
    104. 	
    105. 	<dependency>
    106. 		<groupId>com.alibaba.fastjson2groupId>
    107. 		<artifactId>fastjson2artifactId>
    108. 		<version>2.0.41version>
    109. 	dependency>
    110. 	
    111. 	<dependency>
    112. 		<groupId>com.fasterxml.jackson.coregroupId>
    113. 		<artifactId>jackson-databindartifactId>
    114. 		<version>2.15.2version>
    115. 	dependency>
    116.  
    117. 	
    124. 	
    125. 	<dependency>
    126. 		<groupId>jakarta.servletgroupId>
    127. 		<artifactId>jakarta.servlet-apiartifactId>
    128. 		<version>6.0.0version>
    129. 		<scope>providedscope>
    130. 	dependency>
    131.     
    132.     <dependency>
    133.         <groupId>org.apache.tomcatgroupId>
    134.         <artifactId>tomcat-apiartifactId>
    135.         <version>10.1.13version>
    136.     dependency>
    137.     
    138.     <dependency>
    139.         <groupId>org.springframeworkgroupId>
    140.         <artifactId>spring-webmvcartifactId>
    141.         <version>${spring-version}version>
    142.     dependency>
    143.  
    144. 	      
    145. 	<dependency>
    146. 		<groupId>commons-langgroupId>
    147. 		<artifactId>commons-langartifactId>
    148. 		<version>2.6version>
    149. 	dependency>
    150.  
    151. 	
    152. 	<dependency>
    153. 		<groupId>com.github.qcloudsmsgroupId>
    154. 		<artifactId>qcloudsmsartifactId>
    155. 		<version>1.0.6version>
    156. 	dependency>
    157.  
    158. 	
    159. 	<dependency>
    160. 		<groupId>org.apache.poigroupId>
    161. 		<artifactId>poiartifactId>
    162. 		<version>5.2.3version>
    163. 	dependency>
    164. 	
    165. 	<dependency>
    166. 		<groupId>org.apache.poigroupId>
    167. 		<artifactId>poi-ooxmlartifactId>
    168. 		<version>5.2.3version>
    169. 	dependency>
    170.  
    171. 	
    172. 	<dependency>
    173. 		<groupId>redis.clientsgroupId>
    174. 		<artifactId>jedisartifactId>
    175. 		<version>3.5.2version>
    176. 	dependency>
    177. 	<dependency>  
    178. 		<groupId>org.apache.commonsgroupId>
    179. 		<artifactId>commons-pool2artifactId>
    180. 		<version>2.10.0version>
    181. 	dependency>
    182.         
    204. dependencies>

    2.2 Spring配置文件(.xml)

    1. "1.0" encoding="UTF-8"?>
    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3.        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4.        xmlns:context="http://www.springframework.org/schema/context"
    5.        xmlns:aop="http://www.springframework.org/schema/aop"
    6.        xmlns:tx="http://www.springframework.org/schema/tx"
    7.        xmlns:p="http://www.springframework.org/schema/p" 
    8.        xmlns:mvc="http://www.springframework.org/schema/mvc"
    9.        xsi:schemaLocation="http://www.springframework.org/schema/beans
    10.         http://www.springframework.org/schema/beans/spring-beans.xsd
    11.         http://www.springframework.org/schema/context
    12.         http://www.springframework.org/schema/context/spring-context.xsd
    13.         http://www.springframework.org/schema/aop
    14.         http://www.springframework.org/schema/aop/spring-aop.xsd
    15.         http://www.springframework.org/schema/tx
    16.         http://www.springframework.org/schema/tx/spring-tx.xsd 
    17.         http://www.springframework.org/schema/mvc 
    18.         http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    19.  
    20.     
    21.     <context:property-placeholder location="classpath:config.properties" file-encoding="utf-8"/>
    22.  
    23. 	
    24. 	<context:component-scan base-package="xyz.aboluo" use-default-filters="false">  
    25.         <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>  
    26.         <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>  
    27. 	context:component-scan>
    28.  
    29.     
    30.     <aop:aspectj-autoproxy/>
    31.  
    32.     
    33.     <bean id="user" class="xyz.aboluo.User">
    34.         
    35.         <property name="name" value="${aaa}">property>
    36.         <property name="age" ref="${bbb}">property>
    37.         
    38.         <constructor-arg name="hobby" value="${ccc}"/>
    39.     bean>
    40.  
    41. 	
    42. 	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    43. 		<property name="driverClassName" value="${mysql.driver}"/>
    44. 		<property name="url" value="${mysql.url}"/>
    45. 		<property name="username" value="${mysql.username}"/>
    46. 		<property name="password" value="${mysql.password}"/>
    47. 	bean>
    48. 	
    49. 	<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
    50. 		<property name="driverClassName" value="${mysql.driver}"/>
    51. 		<property name="url" value="${mysql.url}"/>
    52. 		<property name="username" value="${mysql.username}"/>
    53. 		<property name="password" value="${mysql.password}"/>
    54. 	bean>
    55. 	
    56. 	<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    57. 		<property name="driverClass" value="${mysql.driver}"/>
    58. 		<property name="jdbcUrl" value="${mysql.url}"/>
    59. 		<property name="user" value="${mysql.username}"/>
    60. 		<property name="password" value="${mysql.password}"/>
    61. 	bean>
    62.     
    63. 	<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    64. 		<property name="dataSource" ref="dataSource"/>   
    65. 	bean>
    66.     
    67.     <tx:annotation-driven transaction-manager="txManager"/>
    68.  
    69.     
    70.     <import resources="spring.xml"/>
    71. beans>

    3 IOC

            底层核心原理是JAVA反射

            IOC(Inversion Of Control)控制反转(创建对象不再时通过new,而是交给IOC容器)

            Spring通过IOC容器来管理所有JAVA对象的实例化和初始化、控制对象与对象之间的依赖关系,这些由IOC容器管理的JAVA对象称为Spring Bean(它与由关键字new创建的JAVA对象没有任何区别)

    3.1 IOC实现

    3.1.1 ApplicationContext的主要实现类

            BeanFactory是IOC容器的基本实现,是Spring内部使用的接口,不向开发人员提供

            ApplicationContext是BeanFactory的子接口,提供了更多高级特性,面向开发者(几乎所有场合都可以使用ApplicationContext,而不是更底层的BeanFactory)

    实现类简介
    ClassPathXmlApplicationContext通过读取类路径下的xml配置文件创建IOC容器对象
    AnnotationConfigApplicationContext通过读取配置类创建IOC容器对象
    3.1.3.1 ClassPathXmlApplicationContext
    1. @Test
    2. public void userTest() {
    3. 	// 加载spring配置文件,创建"容器对象"
    4. 	ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
    5. 	// 从容器中获取对应的对象
    6. 	User user = context.getBean("user", User.class);
    7. 	// 使用对象
    8. 	user.aaa();
    9. }
    3.1.3.2 AnnotationConfigApplicationContext
    1. @Test
    2. public void userTest() {
    3. 	// 加载spring配置类,创建"容器对象"
    4. 	ApplicationContext context = new AnnotationConfigApplicationContext(SpringConfig.class);
    5. 	// 从容器中获取对应的对象
    6. 	User user = context.getBean("user", User.class);
    7. 	// 使用对象
    8. 	user.aaa();
    9. }

    3.2 依赖注入DI(Dependency Injection)

            在Spring创建对象过程中,注入对象依赖的属性:

                    (1) set注入: 有空参构造方法,和对应的set方法

                    (2) 构造注入: 有对应的构造方法

                    (3) 注解注入: 有空参构造方法

    3.3 注解开发

    3.3.1 开启组件扫描

    3.3.2 创建对象注解

            被注解的类必须有空参构造方法

            这些注解不能写在接口上,要写在类上

    注解说明
    @Component默认使用类名(首字母小写)
    @Controller通常用于控制层,功能与@Component相同
    @Service通常用于业务层,功能与@Component相同
    @Repository通常用于数据访问层,功能与@Component相同

    3.3.3 依赖注入的注解

    注解说明
    @Autowired

    根据类型去IOC容器匹配类/类的子类/接口实现类

    可以用在类或方法上

    @Qualifier("名称")

    要配合@Autowired使用

    根据类型和名称去IOC容器进行匹配

    @Value("值")或("${key}")

    基本数据类型和String类型

    不能用作静态变量(static),不能用作常量(final)

    3.3.4 静态依赖注入

            @Autowired不能作用在静态成员上,但可以在类中先声明静态成员变量,然后用@Autowired作用在非静态set方法上来进行属性注入,间接达到"静态依赖注入"的效果

    1. @Component
    2. public class Common {
    3.     /**
    4.      * 静态声明
    5.      */
    6.     private static StringRedisTemplate stringRedisTemplate;
    7.  
    8.     @Autowired
    9.     public void setStringRedisTemplate(StringRedisTemplate stringRedisTemplate) {
    10.         Common.stringRedisTemplate = stringRedisTemplate;
    11.     }
    12. }

    3.4 全注解开发

            用配置类来替代xml配置文件

    注解

    说明

    @Import

    用在Spring配置类上

    可以引入配置类

    也可以引入Controller,Service,POJO等类,被@Import引入的类可以不写@Component,@Service等注解,依然会被注册进SpringIOC容器

    @Scope("singleton/prototype")

    用于指定bean对象的作用范围(默认singleton)

    可以不配合单独使用,该bean被@Import引入Spring配置类即可生效

    可以配合@Component等注解,也可以配合@Bean注解

    @Bean

    将方法的返回值作为Bean交给SpringIOC容器管理

    如果方法需要参数,会从IOC容器获取(默认按类型注入/多个匹配按形参名注入)

    1. @Configuration  //配置类注解
    2. @Import({DataSourceConfig.class,TransactionConfig.class})  //将类注册进SpringIOC容器 ; 引入其他配置类
    3. @ComponentScan(value = "xyz.aboluo", excludeFilters = @ComponentScan.Filter(
    4.         type = FilterType.ANNOTATION,  //按注解类型过滤(不扫描)
    5.         classes = {Controller.class, Service.class}
    6. ), includeFilters = @ComponentScan.Filter(
    7.         type = FilterType.ANNOTATION,  //按注解类型过滤(只扫描)
    8.         classes = {Controller.class, Service.class}
    9. ))  //开启组件扫描(配置类也要在其中)
    10. @PropertySource(value = "config.properties", encoding = "utf-8")  //引入properties文件
    11. @EnableAspectJAutoProxy  //开启Spring对”注解AOP”的支持
    12. @EnableTransactionManagement  //开启Spring对”注解事务”的支持(需要有对应的"事务管理器"交给SpringIOC容器)
    13. @MapperScan({"xyz.aboluo.dao","xyz.aboluo.dao2"})  //dao接口包扫描
    14. @EnableWebMvc  //开启"json数据转换为对象"的功能,方法形参前加@RequestBody(一个方法只能使用1次)
    15. public class SpringConfig {
    16.     //事务管理器
    17.     @Bean
    18.     public DataSourceTransactionManager getDataSourceTransactionManager(DataSource dataSource) {
    19.         DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
    20.         dataSourceTransactionManager.setDataSource(dataSource);
    21.         return dataSourceTransactionManager;
    22.     }
    23.  
    24.     //Spring整合Mybatis
    25.     @Bean
    26.     @Scope("prototype")
    27.     public SqlSessionFactoryBean getSqlSessionFactoryBean(DataSource dataSource, ApplicationContext applicationContext) {
    28.         SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
    29.         //注入数据源
    30.         sqlSessionFactoryBean.setDataSource(dataSource);
    31.         //给某一包下的所有JavaBean起别名(类名就是别名,不区分大小写)
    32.         sqlSessionFactoryBean.setTypeAliasesPackage("xyz.aboluo.pojo");
    33.         //读取mybatis的主配置文件(非必读)
    34. //        sqlSessionFactoryBean.setConfigLocation(applicationContext.getResource("classpath:mybatisMain.xml"));
    35.         //读取mybatis的映射配置文件(非必读,只要保证xml和dao接口有相同的包路径并且同名即可,或者使用@Select等注解开发)
    36. //        List Resources = new ArrayList<>();
    37. //        Resources.add(applicationContext.getResource("classpath:xyz/aboluo/dao/UserDao.xml"));
    38. //        Resources.add(applicationContext.getResource("classpath:xyz/aboluo/dao/SudokuDao.xml"));
    39. //        sqlSessionFactoryBean.setMapperLocations(Resources.toArray(new Resource[0]));
    40.         return sqlSessionFactoryBean;
    41.     }
    42.  
    43.     //配置dao层接口包扫描(可以用@MapperScan替代)
    44. //    @Bean
    45. //    public MapperScannerConfigurer getMapperScannerConfigurer() {
    46. //        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
    47. //        mapperScannerConfigurer.setBasePackage("xyz.aboluo.dao");
    48. //        return mapperScannerConfigurer;
    49. //    }
    50. }
    51.  
    52. public class DataSourceConfig {
    53.     @Value("${mysql.driver}")
    54.     private String mysqlDriver;
    55.     @Value("${mysql.url}")
    56.     private String mysqlUrl;
    57.     @Value("${mysql.username}")
    58.     private String mysqlUsername;
    59.     @Value("${mysql.password}")
    60.     private String mysqlPassword;
    61.  
    62.     //数据源
    63.     @Bean(name = "dataSource")
    64.     public DriverManagerDataSource getDataSource() {
    65.         DriverManagerDataSource dataSource = new DriverManagerDataSource();
    66.         dataSource.setDriverClassName(mysqlDriver);
    67.         dataSource.setUrl(mysqlUrl);
    68.         dataSource.setUsername(mysqlUsername);
    69.         dataSource.setPassword(mysqlPassword);
    70.         return dataSource;
    71.     }
    72. }
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  • 原文地址：https://blog.csdn.net/SunnerChen/article/details/132811558