Spring在Web项目中的应用-添加ServletContext监听器

青旅半醒 2022-06-17 02:58 205阅读 0赞

# 添加ServletContext监听器 #

**ServletContext初始化时创建Spring容器**

获取容器

package com.hk.ssh.servlets;
    
    import java.io.IOException;
    
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    import org.springframework.web.context.WebApplicationContext;
    
    import com.hk.ssh.beans.Student;
    import com.hk.ssh.service.IStudentService;
    
    public class RegisterServlet extends HttpServlet {
    
        public void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            request.setCharacterEncoding("utf-8");
            String name = request.getParameter("name");
            String ageStr = request.getParameter("age");
            Integer age = Integer.valueOf(ageStr);
    
            Student student = new Student(name,age);
            //1、创建Spring 容器(这种创建方式每来一次请求就会创建一个ApplicationContext)
            //ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
            /** * 采用如下方式创建Spring容器，在ServletContext初始化是创建容器 * ServletContext只初始化一次，所以整个web运用都只会有一个Spring容器 */
            ServletContext application = request.getSession().getServletContext();
            WebApplicationContext ac = (WebApplicationContext) application.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
            //2、从容器中获取Service对象
            IStudentService service = (IStudentService) ac.getBean("studentService");
            //3、调用Service的addStudent()
            service.addStudent(student);
            request.getRequestDispatcher("/welcome.jsp").forward(request, response);
        }
    
    
    }

## 获取Spring容器还有一个方法 ##

WebApplicationContext ac =WebApplicationContextUtils.getRequiredWebApplicationContext(this.getServletContext());

## 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">
        
        <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>
    
    
      <servlet>
        <servlet-name>Register-Servlet</servlet-name>
        <servlet-class>com.hk.ssh.servlets.RegisterServlet</servlet-class>
      </servlet>
    
      <servlet-mapping>
        <servlet-name>Register-Servlet</servlet-name>
        <url-pattern>/registerServlet</url-pattern>
      </servlet-mapping>
    
    </web-app>

**完整项目源码：**[http://pan.baidu.com/s/1slEY7JR][http_pan.baidu.com_s_1slEY7JR]

[http_pan.baidu.com_s_1slEY7JR]: http://pan.baidu.com/s/1slEY7JR