Spring MVC 实践 - Base

Posted 菜鸟-翡青

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Spring MVC 实践

标签 ： Java与Web

Spring Web MVC

Spring-Web-MVC是一种基于请求驱动的轻量级Web-MVC设计模式框架, Spring MVC使用MVC架构思想, 对Web层进行职责解耦,使用请求-响应模型将数据、业务与视图进行分离, 简化开发.

MVC

MVC(模型-视图-控制器)是一个以设计界面应用程序为基础的架构模式,通过分离模型-视图-控制器在应用中的角色将业务逻辑从界面中解耦:

  • 模型负责封装应用数据和业务逻辑;
  • 视图仅负责展示数据;
  • 控制器负责接收用户请求,并调用模型(Service/Manger/DAO)来处理业务逻辑.模型可能会返回一些数据需要在视图层展示,控制器就需要整理模型数据并调用视图展示.

MVC模式的核心思想就是将业务逻辑从界面中分离出来,允许它们单独改变而不会相互影响.
技术分享

Spring MVC

Spring MVC框架是基于Java语言的MVC架构具体实现.他的设计围绕DispatcherServlet展开,DispatcherServlet负责将请求分派给指定的Controller(Handler),通过可配置的HandlerMapping、HandlAdapter、Controller、ViewResolver来处理请求拿到数据并填充对应的视图View:
技术分享

组件 名称 描述
DispatcherServlet 调度器/前端控制器 DispatcherServlet是前端控制器模式的具体实现(详细可参考Front Controller),他提供了整个Web应用的集中访问点,截获请求并将其分派给指定的Controller,相当于MVC中的C. 他的存在降低了组件之间的耦合性.
HandlerMapping 处理器映射器 HandlerMapping负责根据用户请求URI找到对应的Controller与Interceptor,并将它们封装在HandlerExecutionChain中返回给DispatcherServlet.
HandlAdapter 处理器适配器 Spring MVC通过HandlerAdapter执行Controller,这是适配器模式的应用,通过扩展适配器可以执行更多类型的Controller.
Controller 处理器 Controller(又称Handler)是继DispatcherServlet前端控制器之后的后端控制器,在DispatcherServlet的控制下Controller对具体的用户请求进行处理.
ViewResolver 视图解析器 负责将Model数据填充到View, 组合生成视图展示:他首先将逻辑视图名解析成物理视图名,生成View视图对象,最后对View进行渲染(填充数据). Spring默认提供了针对JSP/Velocity/PFD等视图的ViewResolver实现.

初识Spring MVC

需求: 用户列表查询.
  • 创建Maven Web项目
mvn archetype:generate  -DgroupId=com.fq.mvc 
                        -DartifactId=MVC 
                        -DarchetypeArtifactId=maven-archetype-webapp 
                        -DinteractiveMode=false 
                        -DarchetypeCatalog=internal
  • 依赖管理
    在pom.xml中添加Spring、Spring MVC、 Sevlet及Velocity依赖:
<!-- Spring -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</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-context-support</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-expression</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-test</artifactId>
    <version>${spring.version}</version>
</dependency>

<!-- WEB -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>${servlet.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>${spring.version}</version>
</dependency>

<!-- Velocity -->
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>${velocity.version}</version>
</dependency>
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-tools</artifactId>
    <version>${velocity.tools.version}</version>
</dependency>
  • 配置DispatcherServlet(web.xml)
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

    <display-name>MVC</display-name>

    <!-- 配置SpringMVC -->
    <servlet>
        <servlet-name>mvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <!-- contextConfigLocation: 指定MVC配置文件位置 -->
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/mvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <!-- 拦截所有以.do结尾的URL -->
        <servlet-name>mvc</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>
  • 配置HandlerMapping/HandlerAdapter(mvc-servlet.xml)
<?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">
    <!-- 处理器映射器 -->
    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>

    <!-- 处理器适配器 -->
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
</beans>
  • Controller
/**
 * @author jifang
 * @since 16/3/15 下午4:40.
 */
public class UserController implements Controller {

    @Override
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        List<User> users = new ArrayList<>();
        users.add(new User(1, "翡青", new Date(), 1, "浙江-杭州"));
        users.add(new User(2, "小芳", new Date(), 2, "山东-青岛"));

        ModelAndView result = new ModelAndView();
        result.addObject("users", users);
        result.setViewName("users");
        return result;
    }
}
<!-- 装配 Controller -->
<bean name="/mvc/users.do" class="com.fq.mvc.controller.UserController"/>
  • 配置ViewResolver(mvc-servlet.xml)
    由于我们视图选用的是Velocity,因此配置VelocityViewResolver:
<!-- 配置视图解析器 -->
<bean id="viewResolver"
      class="org.springframework.web.servlet.view.velocity.VelocityViewResolver">
    <property name="suffix" value=".vm"/>
    <property name="contentType" value="text/html;charset=UTF-8"/>
    <property name="dateToolAttribute" value="dateTool"/>
    <property name="numberToolAttribute" value="numberTool"/>
    <property name="exposeRequestAttributes" value="false"/>
    <property name="exposeSessionAttributes" value="true"/>
</bean>

<!-- 配置Velocity -->
<bean id="velocityConfigurer"
      class="org.springframework.web.servlet.view.velocity.VelocityConfigurer">
    <!-- 设置VM模板放置位置-->
    <property name="resourceLoaderPath" value="views"/>
    <!-- 防止乱码 -->
    <property name="velocityProperties">
        <props>
            <prop key="input.encoding">UTF-8</prop>
            <prop key="output.encoding">UTF-8</prop>
        </props>
    </property>
</bean>
  • View(/views/users.vm)
<html>
<head>
    <title>用户列表</title>
    <link rel="stylesheet" href="/css/main.css">
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
</head>
<body>
<div id="global">
    <fieldset>
        <legend>用户列表:</legend>

        <table width="100%" border=0>
            <tr>
                <td>ID</td>
                <td>username</td>
                <td>birthday</td>
                <td>sex</td>
                <td>address</td>
            </tr>

            #foreach($user in $users)
                <tr>
                    <td>${user.id}</td>
                    <td>${user.name}</td>
                    <td>${user.birthday}</td>
                    #if(${user.sex} == 1)
                        <td>男</td>
                    #else
                        <td>女</td>
                    #end
                    <td>${user.address}</td>
                </tr>
            #end
        </table>
    </fieldset>
</div>
</body>
</html>

参考: main.css地址:OSChina

小结

  • 前端控制器
    Spring MVC DispatcherServlet的url-pattern有两种配置方式:

    • *.do: 拦截所有以.do结尾的URI.
    • / : 拦截 所有 URI.

  • 处理器映射器
    BeanNameUrlHandlerMapping指定将Bean的Name作为URI映射; Spring还提供了SimpleUrlHandlerMapping将URI和Controller的id统一映射配置.

  • 处理器适配器
    SimpleControllerHandlerAdapter对所有实现了Controller接口的JavaBean适配.Spring还提供HttpRequestHandlerAdapter对所有实现了HttpRequestHandler接口的JavaBean适配.

  • 视图解析器
    前面使用Velocity作为视图展示,如果使用的是JSP的话, 需要配置另一种视图解析器InternalResourceViewResolver:

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <!-- "JstlView"表示可以在JSP页面JSTL标签库,所以需要在项目中添加JSTL依赖 -->
    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
    <property name="prefix" value="/views"/>
    <property name="suffix" value=".jsp"/>
</bean>

注解初步

从2.5版本开始, Spring引入了注解开发:

  • 注解驱动(mvc-servlet.xml)
    • 从3.1版本开始,Spring MVC使用RequestMappingHandlerMapping 注解式处理器映射器 对标有@ResquestMapping的方法进行映射.
    • 从3.1版本开始,Spring MVC使用RequestMappingHandlerAdapter 注解式处理器适配器 对标记有@ResquestMapping的方法进行适配.
    • Spring MVC使用<mvc:annotation-driven/> 注解驱动自动加载RequestMappingHandlerMapping和RequestMappingHandlerAdapter及其他相关配置. 因此在mvc-servlet.xml最简单有效的配置方式是使用<mvc:annotation-driven/>替代注解处理器和适配器:
<mvc:annotation-driven/>

尽管<mvc:annotation-driven/>很小, 但他具有足够的威力, 它注册了很多的特性, 包括对JSR-303校验、信息转换以及对域格式化的支持.

  • 组件扫描(mvc-servlet.xml):
    使用Spring的组件扫描来省去为每个Controller注册的麻烦:
<context:component-scan base-package="com.fq.mvc.controller"/>
  • 注解Controller
@Controller
@RequestMapping("/mvc")
public class UserController {

    @RequestMapping("/users.do")
    public ModelAndView users() {
        List<User> users = new ArrayList<>();
        users.add(new User(1, "翡青", new Date(), 1, "浙江-杭州"));
        users.add(new User(2, "小芳", new Date(), 2, "山东-青岛"));

        ModelAndView result = new ModelAndView();
        result.addObject("users", users);
        result.setViewName("users");
        return result;
    }
}
使用基于注解的`Controller`有以下优点:
    - 基于注解的`Controller`请求映射关系不存储在配置文件中,使用`@RequestMappeing`便可以对一个方法进行映射.
    - 一个`Controller`内可以有多个处理方法,可以响应多个动作,这样就允许将同一模块的多个操作写在同一个`Controller`里面,便于模块划分,且减少类的数量.

集成MyBatis

  • 通过Spring将各层整合:
    • 持久层DAO(MyBatis的Mapper)注册到Spring容器中.
    • 业务层Service/Manager从Spring容器中拿到DAO接口, 并注册Service服务.
    • 表现层Controller从Spring容器中拿到Service接口, 通过Spring MVC进行数据展示.
      技术分享
    需求: 展示所有用户数据(由于数据模型较简单, 因此从DAO到Controller只使用一个DO对象-User).
  • 依赖管理
<!-- Spring -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</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-context-support</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-expression</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-test</artifactId>
    <version>${spring.version}</version>
</dependency>

<!-- AOP -->
<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>

<!-- WEB -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>${servlet.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>${spring.version}</version>
</dependency>

<!-- Velocity -->
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>${velocity.version}</version>
</dependency>
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-tools</artifactId>
    <version>${velocity.tools.version}</version>
</dependency>

<!-- DB -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.3.0</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>${mysql.version}</version>
</dependency>
<dependency>
    <groupId>com.zaxxer</groupId>
    <artifactId>HikariCP</artifactId>
    <version>${hikaricp.version}</version>
</dependency>

<!-- Spring DB支持 -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>${mybatis.spring.version}</version>
</dependency>

<!-- log -->
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>${logback.version}</version>
</dependency>

集成MyBatis

  • mybatis-configuration.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>
    <mappers>
        <mapper resource="mybatis/mapper/UserDAO.xml"/>
    </mappers>
</configuration>
  • domain: User
/**
 * @author jifang.
 * @since 2016/5/26 11:16.
 */
public class User {

    private int id;

    private String name;

    private Date birthday;

    private int sex;

    private String address;

    public User() {
    }

    public User(int id, String name, Date birthday, int sex, String address) {
        this.id = id;
        this.name = name;
        this.birthday = birthday;
        this.sex = sex;
        this.address = address;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public int getSex() {
        return sex;
    }

    public void setSex(int sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}
  • UserDAO
/**
 * @author jifang
 * @since 16/3/20 下午5:47.
 */
public interface UserDAO {

    List<User> selectAllUsers();
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.fq.mvc.dao.UserDAO">

    <select id="selectAllUsers" resultType="com.fq.mvc.domain.User">
        SELECT *
        FROM user;
    </select>

</mapper>
  • applicationContext-datasource.xml(配置数据源)
<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"
       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">

    <context:property-placeholder location="classpath:db.properties"/>

    <!-- 配置数据源 -->
    <bean id="hikariConfig" class="com.zaxxer.hikari.HikariConfig">
        <property name="driverClassName" value="${mysql.driver.class}"/>
        <property name="jdbcUrl" value="${mysql.url}"/>
        <property name="username" value="${mysql.user}"/>
        <property name="password" value="${mysql.password}"/>
        <property name="maximumPoolSize" value="5"/>
        <property name="maxLifetime" value="700000"/>
        <property name="idleTimeout" value="600000"/>
        <property name="connectionTimeout" value="10000"/>
        <property name="dataSourceProperties">
            <props>
                <prop key="dataSourceClassName">com.mysql.jdbc.jdbc2.optional.MysqlDataSource</prop>
                <prop key="cachePrepStmts">true</prop>
                <prop key="prepStmtCacheSize">250</prop>
                <prop key="prepStmtCacheSqlLimit">2048</prop>
            </props>
        </property>
    </bean>

    <bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <constructor-arg ref="hikariConfig"/>
    </bean>

    <!-- 配置SqlSessionFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis/mybatis-configuration.xml"/>
    </bean>

    <!-- 基于包扫描的mapper配置 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.fq.mvc.dao"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

</beans>
  • db.properties
## Data Source
mysql.driver.class=com.mysql.jdbc.Driver
mysql.url=jdbc:mysql://host:port/db?characterEncoding=utf-8
mysql.user=user
mysql.password=password

集成Service

public interface UserService {

    List<User> getAllUsers();
}
@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDAO dao;

    @Override
    public List<User> getAllUsers() {
        return












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