JavaWeb——request获取相关路径

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        http://localhost:8080/DemoName/AServlet?username=xxx&password=yyy
        request.getScheme();//获取协议，http
        request.getServerName();//获取服务器名，localhost
        request.getServerPort();//获取服务器端口，8080
        request.getContextPath();//获取项目名，/DemoName
        request.getServletPath();//获取Servlet路径，/AServlet
        request.getQueryString();//获取参数部分，即问号后面的部分，username=xxx&password=yyy
        request.getRequestURI();//获取请求URI，即项目名+Servlet路径，/DemoName/AServlet
        request.getRequestURL();//获取请求URL，等于不包括参数的整个路径，http://localhost:8080/DemoName/AServlet
    }