javaweb-共享資料ServletContext

1.建立一個設定資料的類HelloServlet

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        String username = "高天亮";
        context.setAttribute("username",username);
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}      

2.在建立一個接受資料的類GetServlet

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        String username = (String) context.getAttribute("username");
        resp.setContentType("text/html");
        resp.setCharacterEncoding("utf-8");//設定編碼，避免亂碼問題
        resp.getWriter().print("名字：" + username);
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}      

3.給兩個類注冊Servlet

<servlet>
    <servlet-name>hello</servlet-name>
    <servlet-class>com.gao.servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>hello</servlet-name>
    <url-pattern>/hello</url-pattern>
</servlet-mapping>
<servlet>
    <servlet-name>getc</servlet-name>
    <servlet-class>com.gao.servlet.GetServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>getc</servlet-name>
    <url-pattern>/getc</url-pattern>
</servlet-mapping>      

4.測試的時候先運作/Hello設定好傳遞的資料，再運作/getc，即可得到最終的結果