SpringMVC基础系列（二）

傷城~ 2021-09-27 02:23 376阅读 0赞

# 一、SpringMVC处理流程 #

SpringMVC大体处理流程：  
![这里写图片描述][70]

# 二、DispatcherServlet前端控制器 #

**web.xml：**

<?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">
        <context-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/applicationContext.xml</param-value>
        </context-param>
        <listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>
        
        <servlet>
            <servlet-name>dispatcher</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            
            <load-on-startup>1</load-on-startup>
        </servlet>
        <servlet-mapping>
            <servlet-name>dispatcher</servlet-name>
            
            <url-pattern>/</url-pattern>
        </servlet-mapping>
    </web-app>

# 三、SpringMVC入门程序 #

**dispatcher.xml：  
直接配置处理器映射器和处理器适配器比较麻烦，可以使用注解驱动来加载。  
SpringMVC使用`<mvc:annotation-driven>`自动加载RequestMappingHandlerMapping和RequestMappingHandlerAdapter  
可以在springmvc.xml配置文件中使用替代注解处理器和适配器的配置。**

<?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.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">
    
        
        <context:component-scan base-package="controller"/>
    
        
        <mvc:default-servlet-handler/>
    
        
        <mvc:annotation-driven/>
    
        
        
        <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
            <property name="prefix" value="//"/>
            <property name="suffix" value=".jsp"/>
        </bean>
    </beans>

**ItemControllerl：**

@Controller      //@Controller注解：采用注解的方式定义该类为处理请求的Controller类
    public class ItemController {
        @RequestMapping(value = "/item/itemlist.action")
        public ModelAndView itemList(){
            // 创建页面需要显示的商品数据
            List<Items> list = new ArrayList<Items>();
            list.add(new Items(1, "1华为 荣耀8", 2399f, new Date(), "质量好！1"));
            list.add(new Items(2, "2华为 荣耀8", 2399f, new Date(), "质量好！2"));
            list.add(new Items(3, "3华为 荣耀8", 2399f, new Date(), "质量好！3"));
            list.add(new Items(4, "4华为 荣耀8", 2399f, new Date(), "质量好！4"));
            list.add(new Items(5, "5华为 荣耀8", 2399f, new Date(), "质量好！5"));
            list.add(new Items(6, "6华为 荣耀8", 2399f, new Date(), "质量好！6"));
    
            ModelAndView mav = new ModelAndView();
            //数据
            mav.addObject("itemList", list);
            mav.setViewName("WEB-INF/jsp/itemList");
            return mav;
        }
    }

**POJO：**

package pojo;
    
    import java.util.Date;
    
    public class Items { 
        public Items(Integer id, String name, Float price, Date createtime, String detail) {
            super();
            this.id = id;
            this.name = name;
            this.price = price;
            this.createtime = createtime;
            this.detail = detail;
        }
    
        private Integer id;
    
        private String name;
    
        private Float price;
    
        private String pic;
    
        private Date createtime;
    
        private String detail;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name == null ? null : name.trim();
        }
    
        public Float getPrice() {
            return price;
        }
    
        public void setPrice(Float price) {
            this.price = price;
        }
    
        public String getPic() {
            return pic;
        }
    
        public void setPic(String pic) {
            this.pic = pic == null ? null : pic.trim();
        }
    
        public Date getCreatetime() {
            return createtime;
        }
    
        public void setCreatetime(Date createtime) {
            this.createtime = createtime;
        }
    
        public String getDetail() {
            return detail;
        }
    
        public void setDetail(String detail) {
            this.detail = detail == null ? null : detail.trim();
        }
    }

**itemList.jsp：**

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>查询商品列表</title>
    </head>
    <body> 
    <form action="${pageContext.request.contextPath }/item/queryitem.action" method="post">
    查询条件：
    <table width="100%" border=1>
    <tr>
    <td><input type="submit" value="查询"/></td>
    </tr>
    </table>
    商品列表：
    <table width="100%" border=1>
    <tr>
        <td>商品名称</td>
        <td>商品价格</td>
        <td>生产日期</td>
        <td>商品描述</td>
        <td>操作</td>
    </tr>
    <c:forEach items="${itemList }" var="item">
    <tr>
        <td>${item.name }</td>
        <td>${item.price }</td>
        <td><fmt:formatDate value="${item.createtime}" pattern="yyyy-MM-dd HH:mm:ss"/></td>
        <td>${item.detail }</td>
    
        <td><a href="${pageContext.request.contextPath }/itemEdit.action?id=${item.id}">修改</a></td>
    
    </tr>
    </c:forEach>
    
    </table>
    </form>
    </body>
    
    </html>

**运行结果：  
![这里写图片描述][70 1]**

# 四、SpringMVC架构说明 #

**画了个图，用了好久~.~：  
![这里写图片描述][70 2]**

# 五、SpringMVC整合Mybatis #

**applicationContext.xml：**

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" 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-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/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">
    
        <context:property-placeholder location="classpath:db.properties"/>
    
        
        <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
            <property name="driverClassName" value="${jdbc.driver}" />
            <property name="url" value="${jdbc.url}" />
            <property name="username" value="${jdbc.username}" />
            <property name="password" value="${jdbc.password}" />
            <property name="maxActive" value="10" />
            <property name="maxIdle" value="5" />
        </bean>
    
        
        <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
            <property name="dataSource" ref="dataSource"/>
            
            <property name="configLocation" value="classpath:sqlMapConfig.xml"/>
        </bean>
    
        
        <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
            
            <property name="basePackage" value="com.long.springmvc.dao"/>
        </bean>
    
        
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <property name="dataSource" ref="dataSource"/>
        </bean>
    
        
        <tx:annotation-driven transaction-manager="transactionManager"/>
    
    </beans>

**sqlMapper.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>
        
        <typeAliases>
            
            <package name="com.long.springmvc.pojo" />
        </typeAliases>
    </configuration>

**web.xml：**

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
      <display-name>springmvc-mybatis</display-name>
      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
      </welcome-file-list>
    
      <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
      </context-param>
    
      
      <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
      </listener>
    
      
      <filter>
        <filter-name>encoding</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>
      </filter>
    
      <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>*.action</url-pattern>
      </filter-mapping>
    
        
      <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:springmvc.xml</param-value>
        </init-param>
      </servlet>
    
      <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        
        <url-pattern>*.action</url-pattern>
      </servlet-mapping>
    </web-app>

# 六、从Mysql中查询商品列表 #

**ItemController：**

@Controller
    public class ItemController { 
        @Autowired
        private ItemService itemService;
        //入门程序 第一 包类 + 类包 + 方法名
        @RequestMapping(value = "/item/itemlist.action")
        public ModelAndView itemList(){
            //从Mysql中查询
            List<Items> list = itemService.selectItemsList();
            ModelAndView mav = new ModelAndView();
            //数据
            mav.addObject("itemList", list);
            mav.setViewName("itemList");
            return mav;
        }

**Service接口：**

public interface ItemService {
        //查询商品列表
        public List<Items> selectItemsList();
    }

**Service实现类：**

@Service
    public class ItemServiceImpl implements ItemService { 
        @Autowired
        private ItemsMapper itemsMapper;
    
        //查询商品列表
        public List<Items> selectItemsList(){
            return itemsMapper.selectByExampleWithBLOBs(null);
        }
    }

**ItemsMapper接口：**

public interface ItemsMapper {
        List<Items> selectByExample(ItemsExample example);
    }

**ItemsMapper.xml：**

<select id="selectByExample" resultMap="BaseResultMap" parameterType="com.long.springmvc.pojo.ItemsExample" >
        select
        <if test="distinct" >
          distinct
        </if>
        <include refid="Base_Column_List" />
        from items
        <if test="_parameter != null" >
          <include refid="Example_Where_Clause" />
        </if>
        <if test="orderByClause != null" >
          order by ${orderByClause}
        </if>
      </select>

# 七、参数绑定 #

## 简单类型： ##

//去修改页面 入参 id
        @RequestMapping(value = "/itemEdit.action")
    // public ModelAndView toEdit(@RequestParam(value = "id",required = false,defaultValue = "1") Integer idaaq,
        public ModelAndView toEdit(Integer id,
                HttpServletRequest request,HttpServletResponse response
                ,HttpSession session,Model model){
    
            //Servlet时代开发
    // String id = request.getParameter("id");
    
            //查询一个商品
    // Items items = itemService.selectItemsById(Integer.parseInt(id));
            Items items = itemService.selectItemsById(id);
            ModelAndView mav = new ModelAndView();
            //数据
            mav.addObject("item", items);
            mav.setViewName("editItem");
            return mav;
        }

**使用@RequestParam常用于处理简单类型的绑定。**

public String queryItemById(@RequestParam(value = "itemId", required = true, defaultValue = "1")

## 绑定POJO： ##

**如果提交的参数很多，或者提交的表单中的内容很多的时候,可以使用简单类型接受数据,也可以使用pojo接收数据。**

# 八、springmvc与struts2不同 #

**1、springmvc的入口是一个servlet即前端控制器，而struts2入口是一个filter过滤器。  
2、springmvc是基于方法开发(一个url对应一个方法)，请求参数传递到方法的形参，可以设计为单例或多例(建议单例)，struts2是基于类开发，传递参数是通过类的属性，只能设计为多例。  
3、Struts采用值栈存储请求和响应的数据，通过OGNL存取数据， springmvc通过参数解析器是将request请求内容解析，并给方法形参赋值，将数据和视图封装成ModelAndView对象，最后又将ModelAndView中的模型数据通过request域传输到页面。Jsp视图解析器默认使用jstl。**

> **转载请标明出处，原文地址：[https://blog.csdn.net/weixin\_41835916][https_blog.csdn.net_weixin_41835916]  
> 总结整理不容易，如果觉得本文对您有帮助，请点击顶支持一下，您的支持是我写作最大的动力，谢谢。  
> ![这里写图片描述][70 3]**

[70]: /images/20210923/9487ca2be652449797ccfc4ffb7f236d.png
[70 1]: /images/20210923/1dfb179407c84aca998254d9a99da619.png
[70 2]: /images/20210923/2da36578136f417aa6744d0545dbf4c6.png
[https_blog.csdn.net_weixin_41835916]: https://blog.csdn.net/weixin_41835916
[70 3]: /images/20210923/fe543a4fcc6f43fa94441e2a1847eff8.png