在Servlet中获取Web路径和真实路径

UseServlet.java

@WebServlet("/user.do")
public class UseServlet extends HttpServlet{

    private static final long serialVersionUID = 1L;
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //设置字符集格式为utf-8
        //req.setCharacterEncoding("UTF-8");
        String scheme=req.getScheme();//获取请求协议http
        String serverName=req.getServerName();//获取服务器名称localhost
        int serverPort = req.getServerPort();
        String contextPath=req.getContextPath();//返回Web应用的URL入口
        String path=scheme+"://"+serverName+":"+serverPort+"/"+contextPath+"/";
        //getRealPath返回一个给定虚拟路径的真实路径
        String realPath=this.getServletContext().getRealPath("index.jsp");
        req.setAttribute("path", path);
        req.setAttribute("realPath", realPath);
        
        req.getRequestDispatcher("index.jsp").forward(req, resp);
        
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        doPost(req, resp);
    }
}

index.jsp

<form action="user.do" method="post">
        <table align="center">
            <tr>
                <td>Web路径：</td>
                <td><%=(String)request.getAttribute("path") %></td>
            </tr>
            <tr>
                <td>真实路径：</td>
                <td><%=(String)request.getAttribute("realPath") %></td>
            </tr>
            <tr>
                <td colspan="2" align="center">
                <input type="submit" value="获取路径"/>
                <input type="reset" value="重置"/>
                </td>
            </tr>
        </table>
    </form>