spring07:Spring集成web环境

7.1ApplicationContext应用上下文获取方式

1.前期web项目项目准备

创建Userdao接口和实现类

创建Userservice接口和实现类

 3.配置application.xml 

4.创建监听类 当web加载，就调用一次

 

5.配置web.xml

    
    
        contextConfigLocation
        applicationContext.xml
    

    
        com.hzw.listener.ContextLoaderListener
    
    
        UserServlet
        com.hzw.web.UserServlet
    
    
        UserServlet
        /userServlet
    

测试web一加载就调用一次创建上下文对象 ApplicationContext

 7.3 Spring提供获取应用上下文的工具

 我们需要完成两步

1.在web.xml中配置ContextLoaderListener监听器（导入spring-web坐标）

    org.springframework
    spring-web
    5.1.15.RELEASE

2.使用WebApplicationContextUtls获取应用上下文对象

import com.hzw.listener.WebApplicationContextUtils;
import com.hzw.service.UserService;
import org.springframework.context.ApplicationContext;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class UserServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext servletContext = this.getServletContext();
        ApplicationContext app = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        UserService userService = app.getBean(UserService.class);
        userService.save();
    }
}