SpringMVC

一.创建基本SpringMVC项目

1.web.xml配置

<!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>

    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>

    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath*:/spring-mvc*.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>/index.html</welcome-file>
    </welcome-file-list>
</web-app>

2.pom.xml配置

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.myproject</groupId>
    <artifactId>myproject</artifactId>
    <packaging>war</packaging>
    <version>1.0</version>

    <name>com.myproject Maven Webapp</name>
    <url>http://maven.apache.org</url>

    <properties>
        <spring.version>4.1.6.RELEASE</spring.version>
        <mybatis.version>3.2.8</mybatis.version>
        <mybatis-spring.version>1.2.2</mybatis-spring.version>
        <druid.version>1.0.13</druid.version>
        <fastjson.version>1.2.4</fastjson.version>
        <jackson.version>2.2.3</jackson.version>
        <commons-io.version>2.4</commons-io.version>
        <commons-fileupload.version>1.3.1</commons-fileupload.version>
    </properties>

    <dependencies>
        <!-- spring 包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${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-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
            <scope>test</scope>
        </dependency>

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

        <!-- mysql连接 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.34</version>
        </dependency>

        <!-- 数据源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>

        <!-- AOP -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.4</version>
        </dependency>

        <!-- jackson json -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>
    </dependencies>
</project>

3.spring-mvc.xml配置

<?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:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

    <!-- 启用Spring注解 -->
    <mvc:annotation-driven />

    <!-- Spring扫描器 -->
    <context:component-scan base-package="com.myproject" />
    
    <!-- 对静态资源文件的访问  -->
    <mvc:default-servlet-handler />
    
    <!-- Jackson转换器 -->
    <bean id="mappingJacksonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" />
        
    <!-- Mybatis配置 -->
    <import resource="mybatis-config.xml" />
    
    <!-- 数据库接连参数 -->
    <context:property-placeholder location="classpath:mybatis.properties" />
    
</beans> 

4.mybatis-config.xml配置

<?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:tx="http://www.springframework.org/schema/tx"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-4.1.xsd 
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx-4.1.xsd
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
        ">

    <!-- 配置数据源 使用的是Druid数据源 -->
    <bean name="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
        init-method="init" destroy-method="close">
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />

        <!-- 初始化连接大小 -->
        <property name="initialSize" value="0" />
        <!-- 连接池最大使用连接数量 -->
        <property name="maxActive" value="20" />

        <!-- 连接池最小空闲 -->
        <property name="minIdle" value="0" />
        <!-- 获取连接最大等待时间 -->
        <property name="maxWait" value="60000" />
        <property name="poolPreparedStatements" value="true" />
        <property name="maxPoolPreparedStatementPerConnectionSize"
            value="33" />
        <!-- 用来检测有效sql -->
        <property name="validationQuery" value="${validationQuery}" />
        <property name="testOnBorrow" value="false" />
        <property name="testOnReturn" value="false" />
        <property name="testWhileIdle" value="true" />
        <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
        <property name="timeBetweenEvictionRunsMillis" value="60000" />
        <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
        <property name="minEvictableIdleTimeMillis" value="25200000" />
        <!-- 打开removeAbandoned功能 -->
        <property name="removeAbandoned" value="true" />
        <!-- 1800秒，也就是30分钟 -->
        <property name="removeAbandonedTimeout" value="1800" />
        <!-- 关闭abanded连接时输出错误日志 -->
        <property name="logAbandoned" value="true" />
        <!-- 监控数据库 -->
        <property name="filters" value="mergeStat" />
    </bean>

    <!-- MyBatis的xml文件 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="mapperLocations" value="classpath:/mappings/**/*.xml" />
    </bean>

    <!-- 扫描basePackage配置包下的所有接口，创建各自接口的动态代理类 -->
    <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.myproject" />
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
    </bean>

    <!-- 配置事务管理器 -->
    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!-- 注解方式配置事物 -->
    <tx:annotation-driven transaction-manager="transactionManager"
        proxy-target-class="true" />

    <!-- 拦截器方式配置事物 -->
    <tx:advice id="transactionAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="insert" propagation="REQUIRED" />
            <tx:method name="update*" propagation="REQUIRED" />
            <tx:method name="delete*" propagation="REQUIRED" />
            <tx:method name="query" propagation="SUPPORTS" />
            <tx:method name="find*" propagation="SUPPORTS" />
            <tx:method name="search*" propagation="SUPPORTS" />
            <tx:method name="*" propagation="SUPPORTS" />
        </tx:attributes>
    </tx:advice>

    <!-- Spring aop事务管理 -->
    <aop:config>
        <aop:pointcut id="transactionPointcut" expression="execution(* com.myproject.*.service.*.*(..))" />
        <aop:advisor pointcut-ref="transactionPointcut" advice-ref="transactionAdvice" />
    </aop:config>
</beans>

5.mybatis.properties配置

#============================#
#===== Database sttings =====#
#============================#

#oracle database settings
#jdbc.type=oracle
#jdbc.driver=oracle.jdbc.driver.OracleDriver
#jdbc.url=jdbc:oracle:thin:@127.0.0.1:1521:orcl
#jdbc.username=root
#jdbc.password=123456

#mysql database setting
validationQuery=SELECT 1
jdbc.type=mysql
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mysql?useUnicode=true&characterEncoding=utf-8
jdbc.username=root
jdbc.password=123456

配置完成，项目看起来是这样的：

 运行测试主页index.html：

测试SpringMVC：

 

二.SpringMVC工作原理

A.程序启动：

1.springMVC的入口是DispatcherServlet,他继承的关系是：DispatcherServlet→FrameworkServlet→HttpServletBean→HttpServlet→GenericServlet(实现Servlet)。

2.所以程序启动时会执行DispatcherServlet的init(),因为DispatcherServlet没有重写init(),所以按继承顺序往上找,找到了HttpServletBean的init()调用它;

3.init()初始化在web.xml配置DispatcherServlet时的init-param等参数,然后调用initServletBean()方法;

4.FrameworkServlet重写了initServletBean(),因为是被子类调用,所以会执行子类FrameworkServlet的initServletBean();

5.initServletBean()调用了initWebApplicationContext(),这个方法初始化子上下文,然后调用onRefresh(ApplicationContext context)方法;

6.同样,它的子类DispatcherServlet重写了onRefresh(ApplicationContext context),所以执行子类的方法;

7.DispatcherServlet又在onRefresh中调用initStrategies(ApplicationContext context),如图:

initMultipartResolver(context); //文件上传解析，如果请求类型是multipart将通过MultipartResolver进行文件上传解析；
initLocaleResolver(context); //本地化解析
initThemeResolver(context);//主题解析
initHandlerMappings(context); //通过HandlerMapping，将请求映射到处理器
initHandlerAdapters(context); //通过HandlerAdapter支持多种类型的处理器
initHandlerExceptionResolvers(context); //如果执行过程中遇到异常将交给HandlerExceptionResolver来解析
initRequestToViewNameTranslator(context); //直接解析请求到视图名
initViewResolvers(context); //通过ViewResolver解析逻辑视图名到具体视图实现
initFlashMapManager(context); //flash映射管理器

B.处理请求

1.DispatcherServlet拦截用户的请求到HttpServlet的doGet、doPost、doPut、doDelete等方法;

2.其中一个子类FrameworkServlet重写了doGet、doPost、doPut、doDelete等方法,然后调用processRequest;

3.在processRequest调用了doService方法,子类DispatcherServlet重写了doService;

4.最终调到了doService的doDispatch方法。

doDispatch遍历handlerMappings，找到第一个能处理当前请求的HandlerMapping处理器;

然后继续遍历handlerAdapters，同样找到第一个能用的HandlerAdapter适配器;

接着调用所有和当前请求相关的拦截器的前置方法;

再实际调用处理程序;

最后调用所有和当前请求相关的拦截器的后置方法。