2018-03-29

Java中基于反射技术的BaseServlet

 package cn.chuang.web.servlet.base;

 import java.io.IOException;
 import java.lang.reflect.Method;

 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 /**
  * 通用的Servlet
  */
 @WebServlet("/base")
 public class BaseServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#service(HttpServletRequest request, HttpServletResponse response)
     */
    public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            //1.获取方法名称
            String mName = request.getParameter("method");
                //1.1判断参数是否为空 若为空，执行默认的方法
            if(mName == null|| mName.trim().length()==0) {
                mName = "index";
            }
            //2.获取方法对象
            Method method = this.getClass().getMethod(mName, HttpServletRequest.class,HttpServletResponse.class);
            //3.让方法执行，接受返回值
            String path = (String) method.invoke(this, request,response);
            //4.判断返回值是否为空，若不为空则统一处理请求转发
            if(path != null) {
                request.getRequestDispatcher(path).forward(request, response);
            }
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException();
        } 
    }

    public String index(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().println("亲，不要捣乱！");
        return null;
    }
 }