javaweb之servlet-------01ServletContext

ServletContext

1.共享数据

//HttpServlet有getServletContext获取ServletContext对象
servletContext.setAttribute("name","陈耀鹏");


//另外的servlet可以调用getAttribute
Object name = context.getAttribute("name");

2.获取初始化参数

<context-param>
        <param-name>url</param-name>
        <param-value>jdbc</param-value>
    </context-param>

String url = context.getInitParameter("url");
System.out.println(url);

3.请求转发

//转发
 context.getRequestDispatcher("/hello").forward(req,resp) ;

保证在resources可以识别到文件
<resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

4.读取资源文件

username=root
password=123456

InputStream stream = context.getResourceAsStream("/WEB-INF/classes/db.properties");

Properties prop = new Properties();

prop.load(stream);

String username = prop.getProperty("username");