第一步：新建maven项目，项目中添加dao，entity，service，servlet，util包
第二步：导入依赖

第三步：数据库建表

第四步：entity实体包（疯转）

第五步：在util工具包中添加工具类

第六步：Dao包中创建Impl包，Impl包中放EmployeeDaoImpl类和UseDaoImpl类；Employee接口，UseDao接口

第七步：UseDao接口中写能实现登录和注册的方法

public Use findByUse(String username,String password)登录

public Integer register(Use use)(注册)

第八步：EmployeeDao接口写能实现增删改查的方法

public Integer addEmployee(Employee employee)

public Integer delById(Integer id)

public Integer updateEmployee(Employee employee)

public Listfindall()

public Employee findbById(Integer id)

第九步：EmployeeDapImpl类（增删改查功能）

增public Integer addEmployee（Employee employee）{

return supper . executeUpdate("insert into t_emolyee(name,salary,age)value(?,?,?)",new Object[]{

employee.getName();employee.getSalary(),employee.getAge()});}

删public Integer delById(Integer　id){

return super.exectueUpdate("delete  from t_emolyee where id=?",new Objject [ ]{id});}

改public Integer updateEmployee（Employee employee）{

return super.executeUpdate("update t_emolyee set name=?,salary=?,age=? where id=? ",new Object[]{

employee.getName();employee.getSalary(),employee.getAge(),employee.getId()});}

查public Listfindall(){

Listlist=new ArrayList<>();

String sql="select * from t_employee"

Object [] params=null;

rs=super.ececuteQuery(sql,params)'

try catch finally

while(rs.(next)){

Employee employee=new Employee（）；

employee . setId(rs.getInt("id"))

employee . setName(rs.getString("name"))

employee.setSalary(rs.getString("salary"))

employee. setAge(rs.getInt("age"))

list.add(employee)

return list;

查对象

public Employe findById（Integer id）

Employee employee=new Employee（）；

rs=super.ExecuteQuary("select * from t_employee where id=?",new Object []{id});

try catch finally

while (rs.next()){

employee.setId(rs.getInt("id"));

employee.setName(rs.getString("name"));

employee.setSalary(rs.getString("salary"));

employee.setAge(rs.getInt("age"));}

return employee;

第十步：UseDaoImpl类（实现登录和注册）

登录（去查询数据库的数据能否和username和passworad匹配）

public Use findByUse（String username，String password）{

Use uu=null；

rs=super.executeQuary("select * from t_use where username=? and password=?",new Object[]{

username,pasword});

try catch finally

while(rs.next()){

uu=new Use()

uu.setUsername(rs.getString("username"));

uu.setRealname(rs.getString("realname"));

uu.setPaaword(rs.getString("password"));}

super.closecon

return uu;

注册（用添加方法。注册完成后，把注册的值传到数据库）

public Integer register（Use use）{

return super.executeUpdate("insert into t_use(username,realname,password)value(?,?,?)",new Object[]{

use.getUsername(),use.getRealname(),use.getPassword});}

第十一步：

service包中添加Impl包包里放EmployeeServiceImpl类和UseServiceImpl类

service包中的EmployeeServiceImpl有一个EmployeeService接口

service包中的UseServiceImpl有一个UseService接口

接口中的方法与dao接口中的方法一致

第十二步：

在servlet包中添加Servlet 类型的UseServlet类和employeeServlet类

useServlet包：

public class UseServlet extends HttpServlet {
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
UseServiceImpl usi=new UseServiceImpl();
String action=request.getParameter("action");
if (action.equals("register")){
String username = request.getParameter("username");
String realname = request.getParameter("realname");
String password = request.getParameter("password");
Use use=new Use();
use.setUsername(username);
use.setRealname(realname);
use.setPassword(password);
Integer flag = usi.register(use);
if (flag>0){
request.getRequestDispatcher("login.jsp").forward(request,response);
}
}else if (action.equals("login")){
String username=request.getParameter("username");
String password=request.getParameter("password");
Use use=usi.findByUse(username,password);
if (use!=null){
request.getRequestDispatcher("EmployeeServlet?action=employeeList").forward(request,response);
} } } }

第十二步：配置web.xml

http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app\_3\_1.xsd" version="3.1">

EmployeeServlet cn.kgc.servlet.EmployeeServlet
UseServlet cn.kgc.servlet.UseServlet

因为有两个Servlet所以要写两个。上面都写各自的路径，下面都写各自的url名
UseServlet /UseServlet
EmployeeServlet /EmployeeServlet

第十三步：

在webapp中导入css样式（样式是别人给的直接复制粘贴过来）

第十四步：建立register.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

第十五步 建立login . jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

第十六步：建立list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

第十七步.建立EmoployeeServlet类

public class EmployeeServlet extends HttpServlet {
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=utf-8");
String action=request.getParameter("action");
if (action.equals("employeeList")){
EmployeeServiceImpl esi=new EmployeeServiceImpl();
List list = esi.findAll();
request.setAttribute("list",list);
request.getRequestDispatcher("list.jsp").forward(request,response);
}
}
}