【Spring源码分析】2、Spring 传统开发转为注解驱动开发

ゝ一纸荒年。 2022-11-27 00:40 148阅读 0赞

### 文章目录 ###

*  1、传统开发转为注解驱动开发
 *   *   *  （1）spring传统开发
         *  （2）spring注解驱动开发
         *  （3）Spring注解驱动开发核心知识图
 *  2、传统开发转为注解驱动开发（配置文件分析）
 *   *   *  （1）案例：spring包扫描配置
         *  （2）案例：定制http消息转换器为FastJson
         *  （3）案例：配置视图解析器
         *  （4）案例：配置防止sql注入
         *  （5）案例：配置数据库连接池
         *  （6）案例：配置JdbcTemplate注入数据源
         *  （7）案例：配置事务管理器
         *  （8）案例：注入CommonsMultipartResolver处理文件上传
         *  （9）案例：配置Bean解析器的处理级别
         *  （10）案例：配置自定义拦截器
         *  （11）案例：配置获取ApplicationContext工具类
         *  （12）案例：配置全局异常处理类
         *  （13）案例：配置swagger静态资源访问放行
 *  3、测试类的入口方式转变
 *  4、更多细节学习
 *  微信公众号

# 1、传统开发转为注解驱动开发 #

传统开发转为注解驱动开发在实际项目开发过程中，最明显的就是体现在ssm项目转变为springboot项目，原本各式各样的配置文件等，全部被取消了，从而采用零配置文件的方式进行开发。也就是使用java代码的形式进行配置，以下全文分析怎么从传统开发转为注解驱动开发，也就是说，怎么将配置文件一步步转变为注解的形式进行开发  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NzYyMjM3_size_16_color_FFFFFF_t_70_pic_center]

### （1）spring传统开发 ###

spring中，最常见的传统开发为ssm（spring + springmvc + mybatis），通常情况下，我们需要在项目目录的的`src\main\resources`目录中创建`applicationContext.xml`配置文件，然后在`src\main\webapp\WEB-INF\web.xml`配置扫描我们的自定义文件，告诉`DispatcherServlet`加载的文件位置

<?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_3_1.xsd" version="3.1">
             
        
        <servlet>
            <servlet-name>springmvc</servlet-name>
            <servlet-class>
                org.springframework.web.servlet.DispatcherServlet
            </servlet-class>
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:application-context.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
        </servlet>
    </web-app>

`applicationContext.xml`配置文件是ssm中最核心的配置文件，这里我举例说明通常情况下配置了些什么，后面再分析怎么将传统的配置文件转为注解驱动开发

<?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:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:task="http://www.springframework.org/schema/task" xmlns:websocket="http://www.springframework.org/schema/websocket" 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 http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd http://www.springframework.org/schema/websocket http://www.springframework.org/schema/websocket/spring-websocket.xsd">
    
        
        <context:component-scan base-package="cn.tellsea"/>
    
        
        <mvc:annotation-driven>
            
            <mvc:message-converters register-defaults="false">
                
                <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
                <bean class="org.springframework.http.converter.BufferedImageHttpMessageConverter"/>
                
                
                <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                    <constructor-arg value="UTF-8"/>
                </bean>
                
                <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
                    <property name="defaultCharset" value="UTF-8"/>
                    <property name="supportedMediaTypes">
                        <list>
                            
                            <value>text/html;charset=UTF-8</value>
                            <value>application/json</value>
                        </list>
                    </property>
                    <property name="fastJsonConfig" ref="fastJsonConfig"/>
                </bean>
            </mvc:message-converters>
        </mvc:annotation-driven>
    
        
        <bean id="fastJsonConfig" class="com.alibaba.fastjson.support.config.FastJsonConfig">
            
            <property name="charset" value="UTF-8"/>
            <property name="serializerFeatures">
                <list>
                    <value>WriteNullListAsEmpty</value>
                    <value>WriteDateUseDateFormat</value>
                    <value>PrettyFormat</value>
                    <value>WriteMapNullValue</value>
                    <value>WriteNullStringAsEmpty</value>
                    <value>WriteNullListAsEmpty</value>
                    <value>DisableCircularReferenceDetect</value>
                </list>
            </property>
        </bean>
    
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
            <property name="prefix" value="/web/"/>
            <property name="suffix" value=".jsp"/>
            <property name="contentType" value="text/html;charset=UTF-8"/>
        </bean>
    
        
        
        <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
            <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
            
            <property name="url" value="jdbc:mysql://localhost:3306/spring-tellsea?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false"/>
            <property name="username" value="root"/>
            <property name="password" value="123456"/>
            
            <property name="initialSize" value="30"/>
            <property name="minIdle" value="50"/>
            <property name="maxActive" value="300"/>
            
            <property name="maxWait" value="60000"/>
            
            <property name="timeBetweenEvictionRunsMillis" value="60000"/>
            
            <property name="minEvictableIdleTimeMillis" value="300000"/>
            <property name="validationQuery" value="SELECT 'x'"/>
            <property name="testWhileIdle" value="true"/>
            <property name="testOnBorrow" value="false"/>
            <property name="testOnReturn" value="false"/>
            
            <property name="poolPreparedStatements" value="true"/>
            <property name="maxPoolPreparedStatementPerConnectionSize" value="20"/>
            
            <property name="filters" value="stat"/>
            
            <property name="proxyFilters">
                <list>
                    <ref bean="wall-filter"/>
                </list>
            </property>
        </bean>
    
        
        <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"/>
        </bean>
        
        
        <bean id="wall-filter-config" class="com.alibaba.druid.wall.WallConfig" init-method="init">
            
            <property name="dir" value="META-INF/druid/wall/mysql"/>
        </bean>
    
        <bean id="wall-filter" class="com.alibaba.druid.wall.WallFilter">
            <property name="dbType" value="mysql"/>
            <property name="config" ref="wall-filter-config"/>
        </bean>
    
        
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <property name="dataSource" ref="dataSource"/>
        </bean>
    
        
        <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                <tx:method name="save*" propagation="REQUIRED"/>
                <tx:method name="add*" propagation="REQUIRED"/>
                <tx:method name="update*" propagation="REQUIRED"/>
                <tx:method name="delete*" propagation="REQUIRED"/>
                <tx:method name="lock*" propagation="REQUIRED"/>
                <tx:method name="enable*" propagation="REQUIRED"/>
                <tx:method name="exit*" propagation="REQUIRED"/>
                <tx:method name="*" read-only="true"/>
            </tx:attributes>
        </tx:advice>
        
        
        <aop:config expose-proxy="true">
            
            <aop:pointcut id="txPointcut" expression="execution(* cn.tellsea.service..*.*(..))"/>
            
            <aop:advisor pointcut-ref="txPointcut" advice-ref="txAdvice"/>
        </aop:config>
    
        
        <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <property name="defaultEncoding" value="UTF-8"></property>
            <property name="resolveLazily" value="true"></property>
            <property name="maxInMemorySize" value="40960"></property>
            <property name="maxUploadSizePerFile" value="52428800"></property>
        </bean>
    
        
        <bean id="beanNameViewResolver" class="org.springframework.web.servlet.view.BeanNameViewResolver" p:order="0">
        </bean>
    
        
        <mvc:interceptors>
            <mvc:interceptor>
                <mvc:mapping path="/**"/>
                <bean class="cn.tellsea.interceptor.MyInterceptor"/>
            </mvc:interceptor>
        </mvc:interceptors>
        
        
        <bean class="cn.tellsea.util.SpringContextUtils" id="SpringContextUtils"/>
    
        
        <bean id="exceptionResolver" class="cn.tellsea.handle.GlobalExceptionHandle"/>
    
        
        <mvc:resources location="classpath:/META-INF/resources/" mapping="swagger-ui.html"/>
        <mvc:resources location="classpath:/META-INF/resources/webjars/" mapping="/webjars/**"/>
    </beans>

### （2）spring注解驱动开发 ###

spring注解驱动开发的典型代表springboot，全部采用注解的形式进各种配置信息的注入等操作

注解驱动开发就是使用注解的方式，达到扫描、注入、定义等操作，以下两种方式等效

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" 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">
    
    	<bean id="person" class="com.ldc.bean.Person">
    		<property name="age" value="18"></property>
    		<property name="name" value="张三"></property>
    	</bean>
    </beans>

/** * @Description 配置类就等同以前的配置文件 */
    @Configuration //告诉Spring这是一个配置类
    public class MainConfig { 
    
        //相当于xml配置文件中的<bean>标签，告诉容器注册一个bean
        //之前xml文件中<bean>标签有bean的class类型，那么现在注解方式的类型当然也就是返回值的类型
        //之前xml文件中<bean>标签有bean的id，现在注解的方式默认用的是方法名来作为bean的id
        @Bean
        public Person person() { 
            return new Person("lisi",20);
        }
    
    }

### （3）Spring注解驱动开发核心知识图 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NzYyMjM3_size_16_color_FFFFFF_t_70_pic_center 1]

# 2、传统开发转为注解驱动开发（配置文件分析） #

下面，我们通过案例，来体现怎么将传统开发转为注解驱动开发， 案例的核心分析为实际项目中最常见的相关xml配置信息

### （1）案例：spring包扫描配置 ###

传统开发

<context:component-scan base-package="cn.tellsea"/>

注解驱动开发

import org.springframework.context.annotation.ComponentScan;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @ComponentScan("cn.tellsea")
    public class ComponentScanConfig { 
    }

### （2）案例：定制http消息转换器为FastJson ###

传统开发

<mvc:annotation-driven>
            
            <mvc:message-converters register-defaults="false">
                
                <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
                <bean class="org.springframework.http.converter.BufferedImageHttpMessageConverter"/>
                
                
                <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                    <constructor-arg value="UTF-8"/>
                </bean>
                
                <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
                    <property name="defaultCharset" value="UTF-8"/>
                    <property name="supportedMediaTypes">
                        <list>
                            
                            <value>text/html;charset=UTF-8</value>
                            <value>application/json</value>
                        </list>
                    </property>
                    <property name="fastJsonConfig" ref="fastJsonConfig"/>
                </bean>
            </mvc:message-converters>
        </mvc:annotation-driven>
    
        
        <bean id="fastJsonConfig" class="com.alibaba.fastjson.support.config.FastJsonConfig">
            
            <property name="charset" value="UTF-8"/>
            <property name="serializerFeatures">
                <list>
                    <value>WriteNullListAsEmpty</value>
                    <value>WriteDateUseDateFormat</value>
                    <value>PrettyFormat</value>
                    <value>WriteMapNullValue</value>
                    <value>WriteNullStringAsEmpty</value>
                    <value>WriteNullListAsEmpty</value>
                    <value>DisableCircularReferenceDetect</value>
                </list>
            </property>
        </bean>

注解驱动开发

import com.alibaba.fastjson.serializer.SerializerFeature;
    import com.alibaba.fastjson.support.config.FastJsonConfig;
    import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
    import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.MediaType;
    import org.springframework.http.converter.HttpMessageConverter;
    
    import java.util.ArrayList;
    import java.util.List;
    
    /** * Http FastJSON 转换器 * * @author Tellsea * @date 2019/8/13 */
    @Configuration
    public class HttpConverterConfig { 
    
        @Bean
        public HttpMessageConverters fastJsonHttpMessageConverters() { 
            // 1.定义一个converters转换消息的对象
            FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
            // 2.添加fastjson的配置信息，比如: 是否需要格式化返回的json数据
            FastJsonConfig fastJsonConfig = new FastJsonConfig();
            fastJsonConfig.setSerializerFeatures(
                    SerializerFeature.WriteNullListAsEmpty,
                    SerializerFeature.WriteDateUseDateFormat,
                    SerializerFeature.PrettyFormat,
                    SerializerFeature.WriteMapNullValue,
                    SerializerFeature.WriteNullStringAsEmpty,
                    SerializerFeature.WriteNullListAsEmpty,
                    SerializerFeature.DisableCircularReferenceDetect
            );
            // 3.在converter中添加配置信息
            fastConverter.setFastJsonConfig(fastJsonConfig);
            // 4.处理中文乱码问题
            List<MediaType> fastMediaTypes = new ArrayList<>();
            fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
            fastConverter.setSupportedMediaTypes(fastMediaTypes);
            // 5.将converter赋值给HttpMessageConverter
            HttpMessageConverter<?> converter = fastConverter;
            // 6.返回HttpMessageConverters对象
            return new HttpMessageConverters(converter);
        }
    }

类中使用了springboot的消息转换器`HttpMessageConverters`，当然也可以使用spring原生的方式改写，我这里以实际使用的案例为准

### （3）案例：配置视图解析器 ###

传统开发

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
            <property name="prefix" value="/web/"/>
            <property name="suffix" value=".jsp"/>
            <property name="contentType" value="text/html;charset=UTF-8"/>
        </bean>

注解驱动开发

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.view.InternalResourceViewResolver;
    import org.springframework.web.servlet.view.JstlView;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class SpringMvcConfig { 
     
        @Bean
        public InternalResourceViewResolver internalResourceViewResolver() { 
            InternalResourceViewResolver resolver = new InternalResourceViewResolver();
            resolver.setViewClass(JstlView.class);
            resolver.setPrefix("/web/");
            resolver.setSuffix(".jsp");
            resolver.setContentType("text/html;charset=UTF-8");
            return resolver;
        }
    }

在springboot中，配置视图解析器可以直接通过`application.yml`文件进行配置

### （4）案例：配置防止sql注入 ###

传统开发

<bean id="wall-filter-config" class="com.alibaba.druid.wall.WallConfig" init-method="init">
            
            <property name="dir" value="META-INF/druid/wall/mysql"/>
        </bean>
    
        <bean id="wall-filter" class="com.alibaba.druid.wall.WallFilter">
            <property name="dbType" value="mysql"/>
            <property name="config" ref="wall-filter-config"/>
        </bean>

注解驱动开发

import com.alibaba.druid.wall.WallConfig;
    import com.alibaba.druid.wall.WallFilter;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class DruidDataSourceConfig { 
    
        @Bean("wall-filter-config")
        public WallConfig wallConfig() { 
            WallConfig wallConfig = new WallConfig();
            wallConfig.setDir("META-INF/druid/wall/mysql");
            return wallConfig;
        }
    
        @Bean("wall-filter")
        public WallFilter wallFilter() { 
            WallFilter wallFilter = new WallFilter();
            wallFilter.setDbType("mysql");
            wallFilter.setConfig(wallConfig());
            return wallFilter;
        }
    }

### （5）案例：配置数据库连接池 ###

传统开发

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
            <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
            
            <property name="url" value="jdbc:mysql://localhost:3306/spring-tellsea?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false"/>
            <property name="username" value="root"/>
            <property name="password" value="123456"/>
            
            <property name="initialSize" value="30"/>
            <property name="minIdle" value="50"/>
            <property name="maxActive" value="300"/>
            
            <property name="maxWait" value="60000"/>
            
            <property name="timeBetweenEvictionRunsMillis" value="60000"/>
            
            <property name="minEvictableIdleTimeMillis" value="300000"/>
            <property name="validationQuery" value="SELECT 'x'"/>
            <property name="testWhileIdle" value="true"/>
            <property name="testOnBorrow" value="false"/>
            <property name="testOnReturn" value="false"/>
            
            <property name="poolPreparedStatements" value="true"/>
            <property name="maxPoolPreparedStatementPerConnectionSize" value="20"/>
            
            <property name="filters" value="stat"/>
            
            <property name="proxyFilters">
                <list>
                    <ref bean="wall-filter"/>
                </list>
            </property>
        </bean>

注解驱动开发

import com.alibaba.druid.filter.Filter;
    import com.alibaba.druid.pool.DruidDataSource;
    import com.alibaba.druid.wall.WallConfig;
    import com.alibaba.druid.wall.WallFilter;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import java.sql.SQLException;
    import java.util.ArrayList;
    import java.util.List;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class DruidDataSourceConfig { 
    
        @Bean("wall-filter-config")
        public WallConfig wallConfig() { 
            WallConfig wallConfig = new WallConfig();
            wallConfig.setDir("META-INF/druid/wall/mysql");
            return wallConfig;
        }
    
        @Bean("wall-filter")
        public WallFilter wallFilter() { 
            WallFilter wallFilter = new WallFilter();
            wallFilter.setDbType("mysql");
            wallFilter.setConfig(wallConfig());
            return wallFilter;
        }
    
        @Bean("dataSource")
        public DataSource dataSource() throws SQLException { 
            DruidDataSource druidDataSource = new DruidDataSource();
            druidDataSource.setDriverClassName("com.mysql.jdbc.Driver");
            druidDataSource.setUrl("jdbc:mysql://localhost:3306/zhengwu?useSSL=false");
            druidDataSource.setUsername("root");
            druidDataSource.setPassword("123456");
            druidDataSource.setInitialSize(30);
            druidDataSource.setMinIdle(50);
            druidDataSource.setMaxActive(300);
            druidDataSource.setMaxWait(60000);
            druidDataSource.setTimeBetweenEvictionRunsMillis(60000);
            druidDataSource.setMinEvictableIdleTimeMillis(300000);
            druidDataSource.setValidationQuery("SELECT 'x'");
            druidDataSource.setTestWhileIdle(true);
            druidDataSource.setTestOnBorrow(false);
            druidDataSource.setTestOnReturn(false);
            druidDataSource.setPoolPreparedStatements(true);
            druidDataSource.setMaxPoolPreparedStatementPerConnectionSize(20);
            druidDataSource.setFilters("stat");
            List<Filter> filters = new ArrayList<>();
            filters.add(wallFilter());
            druidDataSource.setProxyFilters(filters);
            return druidDataSource;
        }
    }

### （6）案例：配置JdbcTemplate注入数据源 ###

传统开发

<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"/>
        </bean>

注解驱动开发

@Bean
        public JdbcTemplate jdbcTemplate() throws SQLException { 
            JdbcTemplate jdbcTemplate = new JdbcTemplate();
            jdbcTemplate.setDataSource(dataSource());
            return jdbcTemplate;
        }

在配置数据库连接池的配置类中，增加JdbcTemplate的Bean配置

### （7）案例：配置事务管理器 ###

传统开发

<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <property name="dataSource" ref="dataSource"/>
        </bean>
    
        
        <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                <tx:method name="save*" propagation="REQUIRED"/>
                <tx:method name="add*" propagation="REQUIRED"/>
                <tx:method name="update*" propagation="REQUIRED"/>
                <tx:method name="delete*" propagation="REQUIRED"/>
                <tx:method name="lock*" propagation="REQUIRED"/>
                <tx:method name="enable*" propagation="REQUIRED"/>
                <tx:method name="exit*" propagation="REQUIRED"/>
                <tx:method name="*" read-only="true"/>
            </tx:attributes>
        </tx:advice>
        
        
        <aop:config expose-proxy="true">
            
            <aop:pointcut id="txPointcut" expression="execution(* cn.tellsea.service..*.*(..))"/>
            
            <aop:advisor pointcut-ref="txPointcut" advice-ref="txAdvice"/>
        </aop:config>

注解驱动开发

import org.aspectj.lang.annotation.Aspect;
    import org.springframework.aop.Advisor;
    import org.springframework.aop.aspectj.AspectJExpressionPointcut;
    import org.springframework.aop.support.DefaultPointcutAdvisor;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.transaction.PlatformTransactionManager;
    import org.springframework.transaction.TransactionDefinition;
    import org.springframework.transaction.interceptor.*;
    
    import java.util.Collections;
    import java.util.HashMap;
    import java.util.Map;
    
    /** * 全局事物配置 * <p> * REQUIRED ：如果当前存在事务，则加入该事务；如果当前没有事务，则创建一个新的事务。 * SUPPORTS ：如果当前存在事务，则加入该事务；如果当前没有事务，则以非事务的方式继续运行。 * MANDATORY ：如果当前存在事务，则加入该事务；如果当前没有事务，则抛出异常。 * REQUIRES_NEW ：创建一个新的事务，如果当前存在事务，则把当前事务挂起。 * NOT_SUPPORTED ：以非事务方式运行，如果当前存在事务，则把当前事务挂起。 * NEVER ：以非事务方式运行，如果当前存在事务，则抛出异常。 * NESTED ：如果当前存在事务，则创建一个事务作为当前事务的嵌套事务来运行；如果当前没有事务，则该取值等价于 REQUIRED 。 * 指定方法：通过使用 propagation 属性设置，例如：@Transactional(propagation = Propagation.REQUIRED) * * @author Tellsea * @date 2020/3/7 */
    @Aspect
    @Configuration
    public class TransactionAdviceConfig { 
    
        /** * 配置方法过期时间，默认-1,永不超时 */
        private final static int TX_METHOD_TIME_OUT = 10;
    
        /** * 配置切入点表达式,这里解释一下表达式的含义 * 1.execution(): 表达式主体 * 2.第一个*号:表示返回类型，*号表示所有的类型 * 3.com.schcilin.goods.service表示切入点的包名 * 4.第二个*号:表示实现包 * 5.*(..)*号表示所有方法名,..表示所有类型的参数 */
        private static final String POITCUT_EXPRESSION = "execution(* cn.tellsea.service..*.*(..))";
    
        @Autowired
        private PlatformTransactionManager platformTransactionManager;
    
        @Bean
        public TransactionInterceptor txadvice() { 
            /* 配置事务管理规则,声明具备管理事务方法名.这里使用public void addTransactionalMethod(String methodName, TransactionAttribute attr)*/
            NameMatchTransactionAttributeSource source = new NameMatchTransactionAttributeSource();
            Map<String, TransactionAttribute> nameMap = new HashMap<>(16);
            /*只读事物、不做更新删除等*/
            /*事务管理规则*/
            RuleBasedTransactionAttribute readOnlyRule = new RuleBasedTransactionAttribute();
            /*设置当前事务是否为只读事务，true为只读*/
            readOnlyRule.setReadOnly(true);
            /* transactiondefinition 定义事务的隔离级别； * PROPAGATION_REQUIRED 如果当前没有事务，就新建一个事务，如果已经存在一个事务中，加入到这个事务中*/
            readOnlyRule.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
            RuleBasedTransactionAttribute requireRule = new RuleBasedTransactionAttribute();
            /*抛出异常后执行切点回滚*/
            requireRule.setRollbackRules(Collections.singletonList(new RollbackRuleAttribute(Exception.class)));
            /*PROPAGATION_REQUIRED:事务隔离性为1，若当前存在事务，则加入该事务；如果当前没有事务，则创建一个新的事务。这是默认值。 */
            requireRule.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
            /*设置事务失效时间，超过10秒,可根据hytrix，则回滚事务*/
            requireRule.setTimeout(TX_METHOD_TIME_OUT);
    
            nameMap.put("add*", requireRule);
            nameMap.put("save*", requireRule);
            nameMap.put("create*", requireRule);
            nameMap.put("insert*", requireRule);
            nameMap.put("update*", requireRule);
            nameMap.put("delete*", requireRule);
            nameMap.put("remove*", requireRule);
            /*进行批量操作时*/
            nameMap.put("batch*", requireRule);
            nameMap.put("get*", readOnlyRule);
            nameMap.put("query*", readOnlyRule);
            nameMap.put("find*", readOnlyRule);
            nameMap.put("select*", readOnlyRule);
            nameMap.put("count*", readOnlyRule);
            source.setNameMap(nameMap);
            return new TransactionInterceptor(platformTransactionManager, source);
        }
    
        /** * 设置切面=切点pointcut+通知TxAdvice * * @return */
        @Bean
        public Advisor txAdviceAdvisorByBusiness() { 
            AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
            pointcut.setExpression(POITCUT_EXPRESSION);
            return new DefaultPointcutAdvisor(pointcut, txadvice());
        }
    }

### （8）案例：注入CommonsMultipartResolver处理文件上传 ###

传统开发

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <property name="defaultEncoding" value="UTF-8"></property>
            <property name="resolveLazily" value="true"></property>
            <property name="maxInMemorySize" value="40960"></property>
            <property name="maxUploadSizePerFile" value="52428800"></property>
        </bean>

注解驱动开发

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.multipart.MultipartResolver;
    import org.springframework.web.multipart.commons.CommonsMultipartResolver;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class MultipartResolverConfig { 
    
        @Bean(name = "multipartResolver")
        public MultipartResolver multipartResolver() { 
            CommonsMultipartResolver resolver = new CommonsMultipartResolver();
            resolver.setDefaultEncoding("UTF-8");
            //resolveLazily属性启用是为了推迟文件解析，以在在UploadAction中捕获文件大小异常
            resolver.setResolveLazily(true);
            resolver.setMaxInMemorySize(40960);
            //上传文件大小 50M 50*1024*1024 bytes
            resolver.setMaxUploadSize(50 * 1024 * 1024);
            return resolver;
        }
    }

springmvc中将MultipartFile转为file，需要注入CommonsMultipartResolver，否则报错

java.lang.ClassCastException: org.springframework.web.multipart.support.StandardMultipartHttpServletRequest$StandardMultipartFile cannot be cast to org.springframework.web.multipart.commons.CommonsMultipartFile

springboot中的相关配置为

spring:
      servlet:
        multipart:
          max-file-size: 20MB
          max-request-size: 100MB
          enabled: true
          resolve-lazily: false

### （9）案例：配置Bean解析器的处理级别 ###

传统开发

<bean id="beanNameViewResolver" class="org.springframework.web.servlet.view.BeanNameViewResolver" p:order="0">
        </bean>

注解驱动开发

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.core.annotation.Order;
    import org.springframework.web.servlet.view.BeanNameViewResolver;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class BeanNameViewResolverConfig { 
    
        @Bean
        @Order(0)
        public BeanNameViewResolver beanNameViewResolver() { 
            return new BeanNameViewResolver();
        }
    }

### （10）案例：配置自定义拦截器 ###

传统开发

<mvc:interceptors>
            <mvc:interceptor>
                <mvc:mapping path="/**"/>
                <bean class="cn.tellsea.interceptor.MyInterceptor"/>
            </mvc:interceptor>
        </mvc:interceptors>

注解驱动开发  
首先编写自定义拦截器，然后将拦截器注册到SpringMVC中

import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /** * @author Tellsea * @date 2020-8-13 */
    public class MyInterceptor implements HandlerInterceptor { 
    
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { 
            System.out.println("在业务处理器处理请求之前被调用...");
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { 
            System.out.println("在业务处理器处理完请求后被调用...");
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { 
            System.out.println("在DispatcherServlet完全处理完请求后被调用...");
        }
    }

注册自定义拦截器

import cn.tellsea.interceptor.MyInterceptor;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class InterceptorConfig implements WebMvcConfigurer { 
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) { 
            registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**");
        }
    }

### （11）案例：配置获取ApplicationContext工具类 ###

传统开发

<bean class="cn.tellsea.util.SpringContextUtils" id="SpringContextUtils"/>

注解驱动开发

import org.springframework.beans.BeansException;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.ApplicationContextAware;
    import org.springframework.stereotype.Component;
    import org.springframework.web.context.request.RequestContextHolder;
    import org.springframework.web.context.request.ServletRequestAttributes;
    
    import javax.servlet.http.HttpServletRequest;
    import java.util.Objects;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Component
    public class SpringContextUtils implements ApplicationContextAware { 
    
        private static ApplicationContext applicationContext;
    
        public static HttpServletRequest getHttpServletRequest() { 
            return ((ServletRequestAttributes) Objects.requireNonNull(RequestContextHolder.getRequestAttributes())).getRequest();
        }
    
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { 
            if (SpringContextUtils.applicationContext == null) { 
                SpringContextUtils.applicationContext = applicationContext;
            }
            System.out.println("SpringUtils: {" + applicationContext + "}");
        }
    
        /** * 获取applicationContext * * @return */
        public static ApplicationContext getApplicationContext() { 
            return applicationContext;
        }
    
        /** * 通过name获取 Bean * * @param name * @return */
        public static Object getBean(String name) { 
            return getApplicationContext().getBean(name);
        }
    
        /** * 通过class获取 Bean * * @param clazz * @param <T> * @return */
        public static <T> T getBean(Class<T> clazz) { 
            return getApplicationContext().getBean(clazz);
        }
    
        /** * 通过name,以及Clazz返回指定的Bean * * @param name * @param clazz * @param <T> * @return */
        public static <T> T getBean(String name, Class<T> clazz) { 
            return getApplicationContext().getBean(name, clazz);
        }
    }

### （12）案例：配置全局异常处理类 ###

传统开发

<bean id="exceptionResolver" class="cn.tellsea.handle.GlobalExceptionHandle"/>

注解驱动开发

import lombok.extern.slf4j.Slf4j;
    import org.springframework.core.Ordered;
    import org.springframework.core.annotation.Order;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.ControllerAdvice;
    import org.springframework.web.bind.annotation.ExceptionHandler;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Slf4j
    @ControllerAdvice
    @Order(value = Ordered.HIGHEST_PRECEDENCE)
    public class GlobalExceptionHandle { 
    
        @ExceptionHandler(value = Exception.class)
        public String exception(Exception e, Model model) { 
            model.addAttribute("code", e.getClass());
            model.addAttribute("info", e.getMessage());
            log.error("【错误原因】{}", e.getClass());
            log.error("【错误描述】{}", e.getMessage());
            e.printStackTrace();
            return "admin/error";
        }
    }

### （13）案例：配置swagger静态资源访问放行 ###

传统开发

<mvc:resources location="classpath:/META-INF/resources/" mapping="swagger-ui.html"/>
        <mvc:resources location="classpath:/META-INF/resources/webjars/" mapping="/webjars/**"/>

注解驱动开发

import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @Configuration
    public class SwaggerConfig implements WebMvcConfigurer { 
    
        @Override
        public void addResourceHandlers(ResourceHandlerRegistry registry) { 
            registry.addResourceHandler("swagger-ui.html").addResourceLocations("classpath:/META-INF/resources/");
            registry.addResourceHandler("/webjars/**").addResourceLocations("classpath:/META-INF/resources/webjars/");
        }
    }

# 3、测试类的入口方式转变 #

下面以读取IOC容器中所有bean为例，检查测试类是否可用

传统开发

import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    /** * @author Tellsea * @date 2020-8-13 */
    public class XmlTest { 
    
        public static void main(String[] args) { 
            ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
            String[] definitionNames = applicationContext.getBeanDefinitionNames();
            for (String name : definitionNames) { 
                System.out.println(name);
            }
        }
    }

注解驱动开发  
需要先定一个配置扫描类，然后注解驱动加载这个扫描类得到IOC容器

import org.springframework.context.annotation.ComponentScan;
    
    /** * @author Tellsea * @date 2020-8-13 */
    @ComponentScan("cn.tellsea")
    public class AppConfig { 
    }

import cn.tellsea.AppConfig;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    /** * @author Tellsea * @date 2020-8-13 */
    public class AnnonTest { 
    
        public static void main(String[] args) { 
            AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);
            String[] definitionNames = applicationContext.getBeanDefinitionNames();
            for (String name : definitionNames) { 
                System.out.println(name);
            }
        }
    }

# 4、更多细节学习 #

*  [Tellsea全系列文章目录][Tellsea]

# 微信公众号 #

![每天Get一个小技巧][Get]

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[Tellsea]: https://blog.csdn.net/qq_38762237/article/details/107228946
[Get]: /images/20221124/20aebce2877b4d8a94f3b9c527161486.png