选课后端

package com.dao;

import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.entity.Message1;
import com.entity.Message2;
import com.entity.Message3;
import com.util.DBUtil;

public class MessageDao {
//登录
public int login(String username, String password,String shenfen) {
String sql=null;
if(shenfen.equals("student")) {
sql="select * from d2 where num='"+username+"'and password='"+password+"'";
}else if(shenfen.equals("teacher")) {
sql="select * from d1 where num='"+username+"'and password='"+password+"'";
}else if(shenfen.equals("manage")) {
sql="select * from d4 where username='"+username+"'and password='"+password+"'";
}
Connection conn=DBUtil.getConn();
Statement st=null;
ResultSet rs=null;
int row=0;
try {
st=conn.createStatement();
rs=st.executeQuery(sql);
if (rs.next()) {
row=1;
}else {
row=0;
}
} catch (Exception e) {
// TODO: handle exception
}
return row;
}
//添加
public boolean add1(Message1 message) {
String sql = "insert into d1(num,tname,tsex,txueyuan,tzhicheng,password)"+"values('" + message.getNum() + "','"
+ message.getTname() + "','" + message.getTsex() + "','" + message.getTxueyuan() + "','"
+ message.getTzhicheng() + "','"+message.getPassword()+"')";
// 创建数据库链接
Connection conn = DBUtil.getConn();
Statement state = null;
boolean f = false;
int a = 0;

try {
state = conn.createStatement();
state.executeUpdate(sql);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭连接
DBUtil.close(state, conn);
}

if (a > 0) {
f = true;
}
return f;
}
public boolean add2(Message2 message) {
String sql = "insert into d2(num,sname,ssex,sclass,smajor,password)"+"values('" + message.getNum() + "','"
+ message.getSname() + "','" + message.getSsex() + "','" + message.getSclass() + "','"
+ message.getSmajor() + "','"+message.getPassword()+"')";
// 创建数据库链接
Connection conn = DBUtil.getConn();
Statement state = null;
boolean f = false;
int a = 0;

try {
state = conn.createStatement();
state.executeUpdate(sql);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭连接
DBUtil.close(state, conn);
}

if (a > 0) {
f = true;
}
return f;
}
public boolean add3(Message3 message) {
String sql = "insert into d3(cnum,cname,cpnum,cteacher)"+"values('" + message.getCnum() + "','"
+ message.getCname() + "','" + message.getCpnum() + "','" + message.getCteacher() + "')";
// 创建数据库链接
Connection conn = DBUtil.getConn();
Statement state = null;
boolean f = false;
int a = 0;

try {
state = conn.createStatement();
state.executeUpdate(sql);
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭连接
DBUtil.close(state, conn);
}

if (a > 0) {
f = true;
}
return f;
}
public static boolean num1(String num) {
boolean flag = false;
String sql = "select * from d1 where num = '" + num + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;

try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}
return flag;
}
public static boolean num2(String num) {
boolean flag = false;
String sql = "select * from d2 where num = '" + num + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;

try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}
return flag;
}
public static boolean num3(String cnum) {
boolean flag = false;
String sql = "select * from d3 where cnum = '" + cnum + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;

try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}
return flag;
}
//查询
public Message1 search(String name) {
String sql = "select * from d1 where name = '" + name + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;
Message1 bean=null;
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
int id2=rs.getInt("id");
String name2 = rs.getString("name");
String sex2 = rs.getString("sex");
String nation2 = rs.getString("nation");
String date2 = rs.getString("date");
String age2=rs.getString("age");
String politics2=rs.getString("politics");
/*bean = new Message1(id2,name2,sex2,nation2,date2,age2,politics2);*/
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}
return bean;
}
//删除
public boolean delete(String name){
String sql="delete from d1 where name='" + name + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
int a = 0;
boolean f = false;
try {
state = conn.createStatement();
a = state.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(state, conn);
}

if (a > 0) {
f = true;
}
return f;
}
//通过姓名查找
public static Message1 getMessageBynum1(String num) {
String sql = "select * from d1 where num ='" + num + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;
Message1 message = null;
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
String num1 = rs.getString("num");
String tname = rs.getString("tname");
String tsex = rs.getString("tsex");
String txueyuan=rs.getString("txueyuan");
String tzhicheng=rs.getString("tzhicheng");
String password=rs.getString("password");
message = new Message1(num1,tname,tsex,txueyuan,tzhicheng,password);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}

return message;
}
public static Message2 getMessageBynum2(String num) {
String sql = "select * from d2 where num ='" + num + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;
Message2 message = null;
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
String num1 = rs.getString("num");
String tname = rs.getString("sname");
String tsex = rs.getString("ssex");
String txueyuan=rs.getString("sclass");
String tzhicheng=rs.getString("smajor");
String password=rs.getString("password");
message = new Message2(num1,tname,tsex,txueyuan,tzhicheng,password);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}

return message;
}
public static String getMessageBynum3(String num) {
String sql = "select * from d1 where num ='" + num + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;
Message1 message = null;
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
String num1 = rs.getString("num");
String tname = rs.getString("tname");
String tsex = rs.getString("tsex");
String txueyuan=rs.getString("txueyuan");
String tzhicheng=rs.getString("tzhicheng");
String password=rs.getString("password");
message = new Message1(num1,tname,tsex,txueyuan,tzhicheng,password);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}

return message.getTname();
}
//修改
public static boolean update12(Message1 message,String name) {

String sql = "update d1 set num='" + message.getNum() + "', tname='" + message.getTname()+"',tsex='"+message.getTsex()+"',txueyuan='"+message.getTxueyuan()+"', tzhicheng='" + message.getTzhicheng() + "', password='" + message.getPassword() + "'where num ='" + name + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
boolean f = false;
int a = 0;

try {
state = conn.createStatement();
a = state.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(state, conn);
}

if (a > 0) {
f = true;
}
return f;
}
public static boolean update22(Message2 message,String name) {

String sql = "update d2 set num='" + message.getNum() + "', sname='" + message.getSname()+"',ssex='"+message.getSsex()+"',Sclass='"+message.getSclass()+"', Smajor='" + message.getSmajor() + "', password='" + message.getPassword() + "'where num ='" + name + "'";
Connection conn = DBUtil.getConn();
Statement state = null;
boolean f = false;
int a = 0;

try {
state = conn.createStatement();
a = state.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(state, conn);
}

if (a > 0) {
f = true;
}
return f;
}
//显示全部
public List<Message3> list()
{
String sql = "select * from d3";
List<Message3> list = new ArrayList<>();
Connection conn = DBUtil.getConn();
Statement state = null;
ResultSet rs = null;
try {
state = conn.createStatement();
rs = state.executeQuery(sql);
while (rs.next()) {
Message3 bean = null;
String cnum=rs.getString("cnum");
String cname = rs.getString("cname");
String cpnum = rs.getString("cpnum");
String cteacher = rs.getString("cteacher");
bean =new Message3(cnum,cname,cpnum,cteacher);
list.add(bean);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil.close(rs, state, conn);
}

return list;
}

}

package com.entity;
//tnum tname tsex txueyaun tzhicheng
public class Message1 {
private String num;
private String tname;
private String tsex;
private String txueyuan;
private String tzhicheng;
private String password;
public String getNum() {
return num;
}
public void setNum(String num) {
this.num = num;
}
public String getTname() {
return tname;
}
public void setTname(String tname) {
this.tname = tname;
}
public String getTsex() {
return tsex;
}
public void setTsex(String tsex) {
this.tsex = tsex;
}
public String getTxueyuan() {
return txueyuan;
}
public void setTxueyuan(String txueyuan) {
this.txueyuan = txueyuan;
}
public String getTzhicheng() {
return tzhicheng;
}
public void setTzhicheng(String tzhicheng) {
this.tzhicheng = tzhicheng;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Message1(String num, String tname, String tsex, String txueyuan, String tzhicheng, String password) {
super();
this.num = num;
this.tname = tname;
this.tsex = tsex;
this.txueyuan = txueyuan;
this.tzhicheng = tzhicheng;
this.password = password;
}
public Message1() {
super();
// TODO 自动生成的构造函数存根
}

}

package com.entity;

public class Message2 {
//num sname ssex sclass smajor
private String num;
private String sname;
private String ssex;
private String sclass;
private String smajor;
private String password;
public String getNum() {
return num;
}
public void setNum(String num) {
this.num = num;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public String getSsex() {
return ssex;
}
public void setSsex(String ssex) {
this.ssex = ssex;
}
public String getSclass() {
return sclass;
}
public void setSclass(String sclass) {
this.sclass = sclass;
}
public String getSmajor() {
return smajor;
}
public void setSmajor(String smajor) {
this.smajor = smajor;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Message2(String num, String sname, String ssex, String sclass, String smajor, String password) {
super();
this.num = num;
this.sname = sname;
this.ssex = ssex;
this.sclass = sclass;
this.smajor = smajor;
this.password = password;
}
}

package com.entity;

public class Message3 {
public String cnum;
public String cname;
public String cpnum;
public String cteacher;
public String getCnum() {
return cnum;
}
public void setCnum(String cnum) {
this.cnum = cnum;
}
public String getCname() {
return cname;
}
public void setCname(String cname) {
this.cname = cname;
}
public String getCpnum() {
return cpnum;
}
public void setCpnum(String cpnum) {
this.cpnum = cpnum;
}
public String getCteacher() {
return cteacher;
}
public void setCteacher(String cteacher) {
this.cteacher = cteacher;
}
public Message3(String cnum, String cname, String cpnum, String cteacher) {
super();
this.cnum = cnum;
this.cname = cname;
this.cpnum = cpnum;
this.cteacher = cteacher;
}

}

package com.service;

import java.util.List;

import com.dao.MessageDao;
import com.entity.Message1;
import com.entity.Message2;
import com.entity.Message3;

//服务层
public class MessageService {

MessageDao mDao = new MessageDao();
//登录
public int login(String username,String password,String shenfen) {
return mDao.login(username,password,shenfen);
}
//添加
public boolean add1(Message1 message) {
boolean f = false;
if(!mDao.num1(message.getNum())) {
mDao.add1(message);
f = true;
}
return f;
}
public boolean add2(Message2 message) {
boolean f = false;
if(!mDao.num2(message.getNum())) {
mDao.add2(message);
f = true;
}
return f;
}
public boolean add3(Message3 message) {
boolean f = false;
if(!mDao.num3(message.getCnum())) {
mDao.add3(message);
f = true;
}
return f;
}
//查找
public Message1 search(String name) {
return mDao.search(name);
}
//删除
public boolean delete(String name) {

mDao.delete(name);
return true;
}
public Message1 getMessageBynum(String num)
{
return mDao.getMessageBynum1(num);
}
//修改
public void update(Message1 message,String num) {
mDao.update12(message,num);
}
//显示所有
public List<Message3> list()
{
return mDao.list();
}
}

package com.servlet;

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

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

import com.dao.MessageDao;
import com.entity.Message1;
import com.entity.Message2;
import com.entity.Message3;
import com.service.MessageService;

@WebServlet("/MessageServlet")
public class MessageServlet extends HttpServlet {
static String wen=null;
static String mo=null;
private static final long serialVersionUID = 1L;

MessageService service = new MessageService();

/**
* 方法选择
*/
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
String method = req.getParameter("method");

if ("add1".equals(method)) {
add1(req, resp);
}else if ("login".contentEquals(method)) {
login(req, resp);
}else if ("add2".equals(method)) {
add2(req, resp);
}else if ("add3".equals(method)) {
add3(req, resp);
}else if ("update11".equals(method)) {
update11(req, resp);
}else if ("update12".equals(method)) {
update12(req, resp);
}else if ("update21".equals(method)) {
update21(req, resp);
}else if ("update22".equals(method)) {
update22(req, resp);
}else if ("list".equals(method)) {
list(req, resp);
}
}
//登录
private void login(HttpServletRequest req,HttpServletResponse resp) throws IOException, ServletException {
req.setCharacterEncoding("utf-8");
String username=req.getParameter("username");
String password=req.getParameter("password");
String shenfen=req.getParameter("shenfen");
int message=service.login(username,password,shenfen);
if(message == 0) {
req.setAttribute("message", "帐号或密码错误！");
req.getRequestDispatcher("login.jsp").forward(req,resp);
} else {
Cookie cookie=new Cookie("username", username);
cookie.setPath("/");
cookie.setMaxAge(60*60*24);
resp.addCookie(cookie);
req.setAttribute("message", "登陆成功");
req.getRequestDispatcher(shenfen+".jsp").forward(req,resp);
}
}
//添加
private void add1(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
req.setCharacterEncoding("utf-8");
//获取数据num tname tsex txueyaun tzhicheng
String num = req.getParameter("num");
String tname = req.getParameter("tname");
String tsex = req.getParameter("tsex");
String txueyuan = req.getParameter("txueyuan");
String tzhicheng = req.getParameter("tzhicheng");
String password = req.getParameter("password");
Message1 message = new Message1(num,tname,tsex,txueyuan,tzhicheng,password);

//添加后消息显示
if(service.add1(message)) {
req.setAttribute("message", "添加成功");
req.getRequestDispatcher("manage.jsp").forward(req,resp);
} else {
req.setAttribute("message", "工号重复，请重新录入");
req.getRequestDispatcher("add1.jsp").forward(req,resp);
}
}
private void add2(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
req.setCharacterEncoding("utf-8");
//snum sname ssex sclass smajor
String num = req.getParameter("num");
String sname = req.getParameter("sname");
String ssex = req.getParameter("ssex");
String sclass = req.getParameter("sclass");
String smajor = req.getParameter("smajor");
String password = req.getParameter("password");
Message2 message = new Message2(num,sname,ssex,sclass,smajor,password);

//添加后消息显示
if(service.add2(message)) {
req.setAttribute("message", "添加成功");
req.getRequestDispatcher("manage.jsp").forward(req,resp);
} else {
req.setAttribute("message", "学号重复，请重新录入");
req.getRequestDispatcher("add2.jsp").forward(req,resp);
}
}
private void add3(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
req.setCharacterEncoding("utf-8");
//snum sname ssex sclass smajor
String cnum = req.getParameter("cnum");
String cname = req.getParameter("cname");
String cpnum = req.getParameter("cpnum");
String cteacher = req.getParameter("cteacher");
Message3 message = new Message3(cnum,cname,cpnum,cteacher);

//添加后消息显示
if(service.add3(message)) {
req.setAttribute("message", "添加成功");
req.getRequestDispatcher("teacher.jsp").forward(req,resp);
} else {
req.setAttribute("message", "课程编号重复，请重新录入");
req.getRequestDispatcher("add3.jsp").forward(req,resp);
}
}
//查询
private void search(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String name = req.getParameter("name");
Message1 message = service.search(name);
if(message == null) {
req.setAttribute("message", "查无此用户！");
req.getRequestDispatcher("search.jsp").forward(req,resp);
} else {
req.setAttribute("message", message);
req.getRequestDispatcher("search1.jsp").forward(req,resp);
}
}
private void search1(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String name = req.getParameter("name");
Message1 message = service.search(name);
if(message == null) {
req.setAttribute("message", "查无此用户！");
req.getRequestDispatcher("search.jsp").forward(req,resp);
} else {
req.setAttribute("message", message);
req.getRequestDispatcher("search2.jsp").forward(req,resp);
}
}

//删除
private void delete(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");

//String name=req.getParameter("name");
//if(MessageDao.name(name))
service.delete(mo);
req.setAttribute("message", "删除成功！");
req.getRequestDispatcher("delete.jsp").forward(req,resp);
}
//通过姓名查找后删除
/* private void getMessageByname(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String name = req.getParameter("name");
Message1 message = service.getMessageByname(name);
mo=name;
if(message==null)
{
req.setAttribute("message", "未找到该用户");
req.getRequestDispatcher("delete.jsp").forward(req, resp);
}
else
{
req.setAttribute("message", message);
req.getRequestDispatcher("delete1.jsp").forward(req,resp);
}
}*/

private void update11(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String num = req.getParameter("num");
Message1 message = MessageDao.getMessageBynum1(num);
wen=num;
if(message==null)
{
req.setAttribute("message","未找到该用户");
req.getRequestDispatcher("teacher.jsp").forward(req, resp);
}
else
{
req.setAttribute("message",message);
req.getRequestDispatcher("update12.jsp").forward(req,resp);
}
}
private void update21(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String num = req.getParameter("num");
Message2 message = MessageDao.getMessageBynum2(num);
wen=num;
if(message==null)
{
req.setAttribute("message","未找到该用户");
req.getRequestDispatcher("update21.jsp").forward(req, resp);
}
else
{
req.setAttribute("message",message);
req.getRequestDispatcher("update22.jsp").forward(req,resp);
}
}
//修改
private void update12(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String num3 = req.getParameter("num");
String tname3 = req.getParameter("tname");
String tsex3 = req.getParameter("tsex");
String txueyuan3 = req.getParameter("txueyuan");
String tzhicheng3 = req.getParameter("tzhicheng");
String password3 = req.getParameter("password");
Message1 message = new Message1(num3,tname3,tsex3,txueyuan3,tzhicheng3,password3);
if(MessageDao.update12(message,wen))
{
req.setAttribute("message","修改成功");
req.getRequestDispatcher("update11.jsp").forward(req,resp);
}
}

private void update22(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String num3 = req.getParameter("num");
String sname3 = req.getParameter("sname");
String ssex3 = req.getParameter("ssex");
String sclass3 = req.getParameter("sclass");
String smajor3 = req.getParameter("smajor");
String password3 = req.getParameter("password");
Message2 message = new Message2(num3,sname3,ssex3,sclass3,smajor3,password3);
if(MessageDao.update22(message,wen))
{
req.setAttribute("message","修改成功");
req.getRequestDispatcher("update21.jsp").forward(req,resp);
}
}

//显示全部
private void list(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");

List<Message3> messages = service.list();
req.setAttribute("messages", messages);
req.getRequestDispatcher("allcourse.jsp").forward(req,resp);
}
}

//DBUtil.java
package com.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil {

public static String db_url = "jdbc:mysql://localhost:3306/select_system?useSSL=false&serverTimezone=GMT";
public static String db_user = "root";
public static String db_pass = "0000";

public static Connection getConn () {
Connection conn = null;

try {
Class.forName("com.mysql.jdbc.Driver");//加载驱动
conn = DriverManager.getConnection(db_url, db_user, db_pass);
} catch (Exception e) {
e.printStackTrace();
}

return conn;
}

/**
* 关闭连接
* @param state
* @param conn
*/
public static void close (Statement state, Connection conn) {
if (state != null) {
try {
state.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

public static void close (ResultSet rs, Statement state, Connection conn) {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

if (state != null) {
try {
state.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

public static void main(String[] args) throws SQLException {
Connection conn = getConn();
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql ="select * from d1";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
if(rs.next()){
System.out.println("空");
}else{
System.out.println("不空");
}
}
}