使用反射对Servlet请求进行转发

朴灿烈づ我的快乐病毒、 2022-06-12 06:06 218阅读 0赞

# 使用反射对Servlet请求进行转发 #

## 基类BaseServlet ##

import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.lang.reflect.Method;
    
    /** * 通用servlet设计 */
    public class BaseServlet extends HttpServlet { 
        @Override
        public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            try {
                //获得字节码对象
                Class<? extends BaseServlet> clazz = this.getClass();
                //获得方法名称
                String m = request.getParameter("method");
                if (null == m || m == "") {
                    m = "index";
                }
                //获得method对象
                Method method = clazz.getMethod(m, HttpServletRequest.class, HttpServletResponse.class);
                //调用方法
                String rst = (String) method.invoke(this, request, response);
                //返回结果判断
                if (rst != null) {
                    request.getRequestDispatcher(rst).forward(request, response);
                }
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException();
            }
        }
    
        public String index(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            return null;
        }
    }

## 新建Servlet继承BaseServlet ##

import arjenlee.domain.Category;
    import arjenlee.service.CategoryService;
    import arjenlee.serviceimpl.CategoryServiceImpl;
    import arjenlee.utils.JsonUtils;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.util.List;
    
    /** * */
    public class CategoryServlet extends BaseServlet { 
    
        public String category(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
            List<Category> clist = null;
            try {
                CategoryService service = new CategoryServiceImpl();
                //使用了ehcache缓存技术
                clist = service.findAll();
                //ajax异步刷新，返回json字符串
                String json = JsonUtils.list2json(clist);
                response.setContentType("text/html;charset=utf-8");
                response.getWriter().write(json);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }
    }

## 使用 ##

http://localhost:8080/project/Category?method=category