重构Servlet将实现员工的增删改查

package web;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;


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

import Util.DAOFactory;

import Dao.EmpDAO;
import Dao.impl.EmpDAOJdbcImpl;
import entity.Emp;

public class ActionServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //由于该Servlet要求处理所有的请求，因此必须判断出请求的来源
        //不同的来源业务有本质的区别，请求来源看规范
        req.setCharacterEncoding("UTF-8");
        String uri=req.getRequestURI();
        String path=uri.substring(uri.lastIndexOf("/"),uri.lastIndexOf("."));
        if(path.equals("/findEmp")){
            //查询所有员工
            findEmp(req,resp);
        }else if(path.equals("/addEmp")){
            //新增员工
            addEmp(req,resp);
        }else if(path.equals("/delEmp")){
            delEmp(req,resp);
            //删除员工
        }else if(path.equals("/loadEmp")){
            //加载员工
            loadEmp(req,resp);
        }else if(path.equals("/modifyEmp")){
            //修改一个员工信息
            modifyEmp(req,resp);
        }
    }
    
    protected void findEmp(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //查询 全部员工
        EmpDAO dao=(EmpDAO)DAOFactory.getInstance("EmpDao");
        List list=dao.findAll();
        resp.setContentType("text/html;charset=UTF-8");
        PrintWriter out=resp.getWriter();
        //输出静态HTML
        //包含版本申明，根元素 head body table 等等
        
        out.println("");
        out.println("");
        out.println("");
        out.println("");
        out.println(" ");
        out.println("");
        out.println("");
        
        out.println("新增");
        out.println("");
        out.println("");
        out.println("");
        out.println("");
        out.println("");
        out.println("");
        out.println("");
        out.println("");
        
        for(Emp e:list){
            out.println("");
            out.println("");
            out.println("");
            out.println("");
            out.println("");
            out.println("");
            out.println("");
        }
        
        out.println("
编号
姓名
薪资
年龄
操作
"+e.getId()+"
"+e.getName()+"
"+e.getSalary()+"
"+e.getAge()+"
删除" +
                    " 修改
");
        out.println("");
        out.println("");
        
    }
    
    protected void addEmp(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //获取对象
        req.setCharacterEncoding("UTF-8");
        String name=req.getParameter("name");
        String salary=req.getParameter("salary");
        String age=req.getParameter("age");
        
        //封装对象
        Emp emp=new Emp();
        emp.setName(name);
        emp.setAge(Integer.parseInt(age));
        emp.setSalary(Double.parseDouble(salary));
        
        //保存
        EmpDAO dao=new EmpDAOJdbcImpl();
        dao.save(emp);
        
        //响应，输出提示信息
/*      resp.setContentType("text/html;charset=utf-8");
        PrintWriter out=resp.getWriter();
        out.println("
新增成功
");
        out.close();*/
        
        //修改响应改为重定向
        resp.sendRedirect("findEmp.do");
        
    }
    
    protected void delEmp(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        //获取参数
        req.setCharacterEncoding("UTF-8");
        String id=req.getParameter("id");
        //删除员工
        EmpDAO dao=new EmpDAOJdbcImpl();
        dao.delete(Integer.parseInt(id));
        //删除后需要 跳转到员工查询页面
        //由于员工的查询和删除是两个独立的组件，可以使用重定向
        resp.sendRedirect("findEmp.do");
    }
    
    protected void loadEmp(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8" );
        String id=req.getParameter("id");
        EmpDAOJdbcImpl dao=new EmpDAOJdbcImpl();
        Emp e=dao.findById(Integer.parseInt(id));
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter out=resp.getWriter();
        out.println("
");
        out.println("
");
        out.println("姓名：
");
        out.println("年龄：
");
        out.println("薪资：
");
        out.println("");
        out.println("
");
        out.close();
        
                
    }

    protected void modifyEmp(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        Emp e=new Emp();
        e.setId(Integer.parseInt(req.getParameter("id")));
        e.setAge(Integer.parseInt(req.getParameter("age")));
        e.setSalary(Double.parseDouble(req.getParameter("salary")));
        e.setName(req.getParameter("name"));
        EmpDAOJdbcImpl dao=new EmpDAOJdbcImpl();
        dao.update(e);
        resp.sendRedirect("findEmp.do");


    }


}