首先根据我浅显的认知,回顾一下Spring,Spring MVC,Mybatis各个小demo中需要做的配置工作。。。
Spring的简略配置
Spring是一个基于IOC和AOP的结构J2EE系统的框架,IOC 反转控制 是Spring的基础,Inversion Of Control 。
简单说就是创建对象由以前的程序员自己new 构造方法来调用,变成了交由Spring创建对象
DI 依赖注入 Dependency Inject. 简单地说就是拿到的对象的属性,已经被注入好相关值了,直接使用即可。
Spring的核心配置文件 是applicationContext.xml。可以通过如下方式,不需要自己new对象,直接获取已经被注入值的对象
<bean name="u" class="com.spring.pojo.User">
<property name="name" value="User 1" />
</bean>
如果使用注解的方式进行配置,应该在applicationContext.xml中写上<context:annotation-config/>。
属性的注解方式有@Autowired(加在属性前或者加在setter前),@Resource(加在属性前,写好值),这样则无需在配置文件中写<property>。对于实体类,也可以进行注解,在class前写上@Component,为属性赋值。
关于需要了解的SpringMVC知识:
WEB-INF目录下需要创建web.xml。在其中进行servlet的配置。包括<servlet-name/>、<servlet-class/>、<url-pattern/>。
在WEB-INF目录下创建springmvc-servlet.xml。其中这里的<servlet-name>与web.xml中的相同。此文件中对访问路径进行相应Controller配置,表面访问某路径交由对应的bean处理。而xxxController实现接口Controller,提供方法handleRequest,获取ModelAndReview的数据,渲染页面。
准备mysql的数据库ssm,建立表格category_。插入一定数据。
在eclipse中建立pojo的package,建立Category.java实体类。
准备接口CategoryMapper,写上各类增删查改方法名。在mapper的package下,新建Category.xml。在Category.xml中,<mapper namespace="..."/>这里必须写上同一个包下CategoryMapper的完整类名,com.ssm.mapper.CategoryMapper。增删查改内容同之前学过的Mybatis。代码如下:
<?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.ssm.mapper.CategoryMapper">
<insert id="add" parameterType="Category" >
insert into category_ ( name ) values (#{name})
</insert>
<delete id="delete" parameterType="Category" >
delete from category_ where id= #{id}
</delete>
<select id="get" parameterType="_int" resultType="Category">
select * from category_ where id= #{id}
</select>
<update id="update" parameterType="Category" >
update category_ set name=#{name} where id=#{id}
</update>
<select id="list" resultType="Category">
select * from category_
</select>
</mapper>
分别建立service和service.impl的package。在两个包下分别建立CategoryService和CategoryServiceImpl。值得注意的是CategoryServiceImpl一定要继承CategoryService。由于在applicationContext.xml中,已经进行了相关bean配置。所以可以通过@Autowired的注解方式获取CategoryMapper对象,并调用list方法。
package com.ssm.service;
import java.util.List;
import com.ssm.pojo.Category;
public interface CategoryService {
List<Category> list();
}
package com.ssm.service.impl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.ssm.mapper.CategoryMapper;
import com.ssm.pojo.Category;
import com.ssm.service.CategoryService;
@Service
public class CategoryServiceImpl implements CategoryService{
@Autowired
CategoryMapper categoryMapper;
public List<Category> list(){
return categoryMapper.list();
}
}
如上所述,访问请求先通过DispatcherServlet,然后访问对应的xxxController类。也就是说,在xxxController类中,开始请求的任务。利用注解在类前标注@Controller,表明这是一个Controller的类。然后通过注解获取categoryService对象。利用categoryService获取种类数据之后,存放在数组中,最终渲染到页面上。
package com.ssm.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import com.ssm.pojo.Category;
import com.ssm.service.CategoryService;
@Controller
@RequestMapping("")
public class CategoryController {
@Autowired
CategoryService categoryService;
@RequestMapping("listCategory")
public ModelAndView listCategory(){
ModelAndView mav = new ModelAndView();
List<Category> cs= categoryService.list();
// 放入转发参数
mav.addObject("cs", cs);
// 放入jsp路径
mav.setViewName("listCategory");
return mav;
}
}
以下是各类配置文件
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"
xmlns:web="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" version="2.5">
<!-- spring的配置文件-->
<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>
<!-- spring mvc核心:分发servlet -->
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- spring mvc的配置文件 -->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:SpringMVC.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
SpringMVC.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" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
<context:annotation-config/>
<context:component-scan base-package="com.ssm.controller">
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
<mvc:annotation-driven />
<mvc:default-servlet-handler />
<!-- 视图定位 -->
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass"
value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
applicationContext.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" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:annotation-config />
<context:component-scan base-package="com.ssm.service" />
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName">
<value>com.mysql.jdbc.Driver</value>
</property>
<property name="url">
<value>jdbc:mysql://localhost:3306/ssm?characterEncoding=UTF-8</value>
</property>
<property name="username">
<value>root</value>
</property>
<property name="password">
<value>admin</value>
</property>
</bean>
<bean id="sqlSession" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="typeAliasesPackage" value="com.ssm.pojo" />
<property name="dataSource" ref="dataSource"/>
<property name="mapperLocations" value="classpath:com/ssm/mapper/*.xml"/>
</bean>
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.ssm.mapper"/>
</bean>
</beans>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" import="java.util.*"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<table align='center' border='1' cellspacing='0'>
<tr>
<td>id</td>
<td>name</td>
</tr>
<c:forEach items="${cs}" var="c" varStatus="st">
<tr>
<td>${c.id}</td>
<td>${c.name}</td>
</tr>
</c:forEach>
</table>