一、Spring?
Spring兴起:2003年,由Rod Johnson创建。总的来说,Spring Framwork从它诞生至今都一直为人所称道,它的伟大之处自此可见一斑。
核心:IOC&AOP
- IOC
全称:Inersion of control-->控制反转。把对象的创建工作交给框架(有意取代EJB)。
IOC和DI:两个概念其实都是阐述同一个内容
- AOP
Aspect Oriented Programming的缩写,意为:面向切面编程
二、如何入门(整合Servlet)?
- 准备jar包:官网下载资源, 导入Core Container中的 4个jar包:
beans
|code
|context
|expression
+4个日志jar包+spring-web-xxx.jar - 配置文件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" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean name="us" class="com.gaga.service.serviceimp.UserServiceImp"> <property name="name" value="张三"></property> </bean> </beans>
- Servlet
public class ServletDemo extends HttpServlet { @Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//这里通过工具类创建工厂,解决:每次请求过来都会解析xml, 创建工厂。如果xml内容很多,就比较的耗时。 WebApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(getServletContext()); UserService userService = (UserService) context.getBean("us"); userService.saveUser(); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } }
-
UserServiceImp
public class UserServiceImp implements UserService { private String name; public void setName(String name) { this.name = name; } public void setName(String name) { this.name = name; } public void saveUser() { System.out.println("UserServiceImp收到了请求--name-------" + name ); } }
- 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"> <servlet> <servlet-name>S</servlet-name> <servlet-class>com.gaga.test.ServletDemo</servlet-class> </servlet>
<!-- 配置监听器 定义监听器, 然后在监听器里面创建工厂 , 存储工厂到一个地方去,以便所有的servlet都能使用到工厂。 --> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!-- 告诉监听器,配置文件在哪里 --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param> <servlet-mapping> <servlet-name>S</servlet-name> <url-pattern>/demo</url-pattern> </servlet-mapping> </web-app>