SpringServletContext简单案例

一、项目结构及相应jar包，如下图

二、UserService代码

package com.hjp.service;

/**
 * Created by JiaPeng on 2015/11/15.
 */
public class UserService {
    public void addUser() {
        System.out.println("add user");
    }
}

三、创建一个HelloServlet，代码：

package com.hjp.web.servlet;

import com.hjp.service.UserService;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import java.io.IOException;

/**
 * Created by JiaPeng on 2015/11/15.
 */
public class HelloServlet extends javax.servlet.http.HttpServlet {
    protected void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
        this.doGet(request, response);
    }

    protected void doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException {
        //方式1，手动从ServletContext作用域中获得内容
        //WebApplicationContext applicationContext = (WebApplicationContext) this.getServletContext().getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
        WebApplicationContext applicationContext= WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
        UserService userService = (UserService) applicationContext.getBean("userService");
        userService.addUser();
    }
}

四、web.xml中配置，主要是注意监听的配置

<?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">
    <!--设置web全局初始化参数，设置配置文件位置
        名称#contextConfigLocation 固定
        值#  "classpath:"表示类路径 (src)
            也可以有子包，写法#classpath:com/hjp/applicationContext.xml
    -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>
    <!--配置监听器，用于加载spring配置文件-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>com.hjp.web.servlet.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/HelloServlet</url-pattern>
    </servlet-mapping>
    <welcome-file-list>
        <welcome-file>/index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

五、applicationContext.xml文件

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       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/aop
                           http://www.springframework.org/schema/aop/spring-aop.xsd
                           http://www.springframework.org/schema/tx
                           http://www.springframework.org/schema/tx/spring-tx.xsd">
    <bean id="userService" class="com.hjp.service.UserService"></bean>
</beans>