Spring如何获取ServletContext

一、获取ServletContext的几种方式

实现WebApplicationInitializer接口，重写onStartup方法

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.springframework.web.WebApplicationInitializer;

public class ApplicationInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        System.out.println(servletContext);
    }
}

使用ServletContextListener

创建一个实现ServletContextListener的监听器

// 必不可少，声明为监听器，注册到web容器中
@WebListener
public class InitContextListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        ServletContext servletContext = servletContextEvent.getServletContext();
        System.out.println(servletContext);
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}

使用ContextLoader

WebApplicationContext webApplicationContext  = ContextLoader.getCurrentWebApplicationContext();
ServletContext servletContext = webApplicationContext.getServletContext();

使用spring自动注入

@Autowired
private ServletContext servletContext;

request获取servletContext

ServletContext servletContext = request.getServletContext();

二、使用ServletContext存取

添加属性：setAttribute(String name,Object ob);

得到值：   getAttribute(String);    //返回Object

删除属性：removeAttribute(String name);