java登录mvc_MVC模式实现登录以及增删改查之登录

灰太狼 2022-11-04 00:53 153阅读 0赞

昆明Java培训班的老师在这里用的不是maven项目,用的一般的web项目,所以需要用到的架包需要自己去下载添加,在项目中,一定注意环境的配置,我用的是jre1.7

1 新建项目

2 建立好MVC的管理包,导入对应的架包servlet

3建立好与数据库对应的实体类teacher.java

public class

Teacher \{

private int tid;

private String tname;

private String tpsw;

public int getTid() \{

return tid;

public void setTid(int tid) \{

this.tid = tid;

public String getTname() \{

return tname;

public void setTname(String tname)

this.tname = tname;

public String getTpsw() \{

return tpsw;

public void setTpsw(String tpsw) \{

this.tpsw = tpsw;

public Teacher(String tname, String

tpsw) \{

super();

this.tname = tname;

this.tpsw = tpsw;

public Teacher(int tid, String

tname, String tpsw) \{

super();

this.tid = tid;

this.tname = tname;

this.tpsw = tpsw;

public Teacher() \{

super();

4在WebContent新建login.jsp文件编写登陆框

action="login" method="post">

3用户名:

type="text" name="tname">

4密码:

type="text" name="tpsw">

type="submit" value="登录">

5 配置web.xml文件对应表单请求login

web.xml文件

注意:配置时要在之前,否则会报错

com.zr.controller.LoginController

/login

6编写对应的请求实体类LoginController.java:继承HttpServlet重写doget(),dopost()方法,根据method请求的不同调用doget或者dopost方法

LoginController.java

import

java.io.IOException;

import

javax.servlet.ServletException;

import

javax.servlet.http.HttpServlet;

import

javax.servlet.http.HttpServletRequest;

import

javax.servlet.http.HttpServletResponse;

import

javax.servlet.http.HttpSession;

import

com.zr.model.Teacher;

import

com.zr.service.valiDateService;

import

com.zr.serviceIm.valiDateServiceImpl;

public class

LoginController  extends HttpServlet\{

protected void

doGet(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException \{

super.doPost(req, resp);

protected void

doPost(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException

//获取前台form表单的input输入框

String

tname=req.getParameter("tname");

String

tpsw=req.getParameter("tpsw");

Teacher tc=new Teacher();

tc.setTname(tname);

tc.setTpsw(tpsw);

valiDateService vds=new

valiDateServiceImpl();

Teacher t=   vds.valiDateTeacher(tc);

HttpSession session=req.getSession();

session.setAttribute("teacher", t);

if (t!=null) \{

//返回的不是空值,重定向到登录成功界面

req.getRequestDispatcher("main.jsp").forward(req, resp);

\} else \{

//返回空值,请求转发到登录界面

resp.sendRedirect("login.jsp");

7从后台dao层写到control层

public interface

TeacherDao \{

/\*\*

\*验证老师是否存在

\* @param tc

\* @return

\*/

public Teacher validateTeacher(Teacher tc);

8.1编写封装类建立与数据库的连接JDBCUtil.java

package

JDBCUtil;

import

java.sql.Connection;

import

java.sql.DriverManager;

import

java.sql.SQLException;

import

java.sql.Statement;

public class JDBCUtil \{

//1.数据库地址 (根据不同的数据标准是不一样)

private final static String DBURL =

"jdbc:mysql://localhost:3306/student\_crm?useUnicode=true&characterEncoding=UTF8";

//2.设置用户和密码

private final static String USERNAME =

"root";

private final static String PASSWORD =

"root";

//3.设置驱动名称(根据不同的数据标准是不一样)

private final static String DBDRIVER =

"com.mysql.jdbc.Driver";

/\*\*

\*获取数据库连接

\* @return 返回数据库连接

\*/

public static Connection getConnection()\{

Connection con = null;

try \{

Class.forName(DBDRIVER);

con = DriverManager.getConnection(DBURL, USERNAME, PASSWORD);

\} catch (ClassNotFoundException e)

// TODO Auto-generated catch

block

e.printStackTrace();

\} catch (SQLException e) \{

// TODO Auto-generated catch

block

e.printStackTrace();

return con;

//关闭连接

public static void closeJDBC(Statement st,Connection con) throws SQLException\{

if(st!=null)\{

st.close();

if(con!=null)\{

con.close();

8.2 dao层的实现

import

java.sql.Connection;

import

java.sql.PreparedStatement;

import

java.sql.ResultSet;

import

java.sql.SQLException;

import

com.zr.dao.TeacherDao;

import

com.zr.model.Teacher;

import

JDBCUtil.JDBCUtil;

public class

TeacherDaoImpl implements TeacherDao\{

/\*\*

\*输入老师的对象,返回老师对象

\* @param args

\*/

public Teacher validateTeacher(Teacher tc)

Teacher teacher=new Teacher();

//sql语句

StringBuffer sql=new

StringBuffer("select \* from teacher where tname=? and tpsw=?");

//获取数据库连接

Connection con=JDBCUtil.getConnection();

try \{

PreparedStatement pst=con.prepareStatement(sql.toString());

pst.setString(1, tc.getTname());

pst.setString(2, tc.getTpsw());

//返回一个结果集

ResultSet rs=pst.executeQuery();

if (rs.next()) \{

//把结果集里面的数据放入对应的teacher对象

teacher=new

Teacher(rs.getInt("tid"),rs.getString("tname"),rs.getString("tpsw"));

\} catch (SQLException e) \{

e.printStackTrace();

return teacher;

9 Service层

public interface

valiDateService \{

/\*\*

\* @param tc

\* @return老师对象

\*根据用户输入值验证老师是否存在

\*/

public Teacher valiDateTeacher(Teacher tc);

10 Service层实现ServiceImpl.java

import

com.zr.dao.TeacherDao;

import

com.zr.daoIm.TeacherDaoImpl;

import

com.zr.model.Teacher;

import

com.zr.service.valiDateService;

public class

valiDateServiceImpl implements valiDateService\{

public Teacher valiDateTeacher(Teacher tc)

//父类的引用指向子类的对象,父类可以直接调用子类的方法

TeacherDao teacherDao=new

TeacherDaoImpl();

//调用dao层的方法验证存在

Teacher

teacher=teacherDao.validateTeacher(tc);

return teacher;

com.zr.controller层

import

java.io.IOException;

import

javax.servlet.ServletException;

import

javax.servlet.http.HttpServlet;

import

javax.servlet.http.HttpServletRequest;

import

javax.servlet.http.HttpServletResponse;

import

javax.servlet.http.HttpSession;

import

com.zr.model.Teacher;

import

com.zr.service.valiDateService;

import

com.zr.serviceIm.valiDateServiceImpl;

public class

LoginController extends HttpServlet \{

protected void doGet(HttpServletRequest

req, HttpServletResponse resp) throws ServletException, IOException \{

super.doPost(req, resp);

protected void doPost(HttpServletRequest

req, HttpServletResponse resp) throws ServletException, IOException \{

//获取前台form表单的input输入框

String tname =

req.getParameter("tname");

String tpsw =

req.getParameter("tpsw");

//将前台对象放入tc对象,作为输入参数

Teacher tc = new Teacher();

tc.setTname(tname);

tc.setTpsw(tpsw);

//调用Service层的方法传入tc对象,并用t接收返回结果

valiDateService vds = new

valiDateServiceImpl();

Teacher t = vds.valiDateTeacher(tc);

//获取JSP作用域session,将老师t对象放入session

HttpSession session = req.getSession();

int a = t.getTid();//最好根据返回的老师的id进行判断

if (a != 0) \{

//返回的有id,重定向到登录成功界面

req.getRequestDispatcher("main.jsp").forward(req, resp);

session.setAttribute("teacher", t);

\} else \{

//返回空值,请求转发到登录界面

req.getRequestDispatcher("login.jsp").forward(req, resp);

java登录mvc_MVC模式实现登录以及增删改查之登录

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