课堂测试用javaweb写一个注册界面，并将数据保存到后台数据库（部分完成）

package Dao; import java.sql.Connection;
import java.sql.Statement; import DBUtil.DBUtil; import Entity.User; public class Dao { public boolean add(User user) {
String sql = "insert into uses1 (username,password,sex,name,stuname,email,xueyuan,xi,banji,year,address,addtext) values('"+ user.getUsername() + "','"+ user.getPassword() +"','"+ user.getSex() +"','"+user.getName() +"','"+ user.getStuname() +"','"+user.getEmail()+"','"+ user.getXueyuan() +"','"+user.getXi()+"','"+user.getBanji()+"','"+user.getYear()+"','"+user.getAddress()+"','"+user.getAddtext()+"')";
Connection conn = DBUtil.getConn();
Statement state = null;
boolean f = false;
int a = 0; try {
state = conn.createStatement();
a=state.executeUpdate(sql);
} catch (Exception e) {
e.printStackTrace();
} finally { DBUtil.close(state, conn);
} if (a > 0) {
f = true;
}
return f; } }

package DBUtil; import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement; /**
* @author Hu
*
*/
public class DBUtil { public static String db_url = "jdbc:mysql://localhost:3306/user?serverTimezone=UTC";
public static String db_user = "root";
public static String db_pass = "123"; public static Connection getConn () {
Connection conn = null; try {
Class.forName("com.mysql.cj.jdbc.Driver");
conn = DriverManager.getConnection(db_url, db_user, db_pass);
} catch (Exception e) {
e.printStackTrace();
} return 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 users";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
if(rs.next()){
System.out.println("空");
}else{
System.out.println("不空");
}
}
}

package Entity; public class User { private String username;
private String password;
private String sex;
private String name;
private String stuname;
private String email;
private String xueyuan;
private String xi;
private String banji;
private String year;
private String address;
private String addtext; public String getUsername() {
return username;
} public void setUsername(String username) {
this.username = username;
} public String getPassword() {
return password;
} public void setPassword(String password) {
this.password = password;
} public String getSex() {
return sex;
} public void setSex(String sex) {
this.sex = sex;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public String getStuname() {
return stuname;
} public void setStuname(String stuname) {
this.stuname = stuname;
} public String getEmail() {
return email;
} public void setEmail(String email) {
this.email = email;
} public String getXueyuan() {
return xueyuan;
} public void setXueyuan(String xueyuan) {
this.xueyuan = xueyuan;
} public String getXi() {
return xi;
} public void setXi(String xi) {
this.xi = xi;
} public String getBanji() {
return banji;
} public void setBanji(String banji) {
this.banji = banji;
} public String getYear() {
return year;
} public void setYear(String year) {
this.year = year;
} public String getAddress() {
return address;
} public void setAddress(String address) {
this.address = address;
} public String getAddtext() {
return addtext;
} public void setAddtext(String addtext) {
this.addtext = addtext;
} public User() {} public User(String username,String password,String sex,String name,String stuname,String email,String xueyuan, String xi,String banji,String year,String address,String addtext) { this.username=username;
this.password=password;
this.sex=sex;
this.name=name;
this.stuname=stuname;
this.email=email;
this.xueyuan=xueyuan;
this.xi=xi;
this.banji=banji;
this.year=year;
this.address=address;
this.addtext=addtext; } }

package Servlet; import java.io.IOException; import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import Dao.Dao; import Entity.User; @WebServlet("/Servlet")
public class Servlet extends HttpServlet {
private static final long serialVersionUID = 1L; public Servlet() {
super(); }
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
String method = req.getParameter("method");
if ("add".equals(method)) {
add(req, resp);
}
} public void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
req.setCharacterEncoding("utf-8");
String username = req.getParameter("username");
String password = req.getParameter("password");
String sex = req.getParameter("sex");
String name = req.getParameter("name");
String stuname = req.getParameter("stuname");
String email = req.getParameter("email");
String xueyuan = req.getParameter("xueyuan");
String xi= req.getParameter("xi");
String banji= req.getParameter("banji");
String year= req.getParameter("year");
String address= req.getParameter("address");
String addtext= req.getParameter("addtext");
User user = new User(username,password,sex,name,stuname,email,xueyuan,xi,banji,year,address,addtext); Dao dao =new Dao();
boolean f=dao.add(user); if(f) {
req.setAttribute("message", "注册成功！");
req.getRequestDispatcher("users.jsp").forward(req,resp);
}
else {
req.setAttribute("message", "注册失败！");
req.getRequestDispatcher("users.jsp").forward(req,resp);
}
}
}

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script> </script>
</head> <body>
<%
Object message = request.getAttribute("message");
if (message != null && !"".equals(message)) {
%>
<script type="text/javascript">
alert("<%=request.getAttribute("message")%>");
</script>
<%
}
%> <table border="0px" cellpadding="10px" cellspacing="0px"
style="width: 50%;margin:auto;background:rgb(195,195,195)" bordercolor="red" >
<form action="Servlet?method=add" method="post"
onsubmit="return check()">
<caption>当前位置：添加学生信息</caption> <tr>
<td>登录账号:</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>登录密码:</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td>性别:</td>
<td>
<select name="sex">
<option value="男">男</option>
<option value="女">女</option>
</select>
</td>
</tr>
<tr>
<td>姓名:</td>
<td><input type="text" name="name"></td>
</tr>
<tr>
<td>学号:</td>
<td><input type="text" name="stuname"></td>
</tr>
<tr>
<td>电子邮箱:</td>
<td><input type="text" name="email"></td>
</tr>
<tr>
<td>所在学院:</td>
<td><input type="text" name="xueyuan"></td>
</tr>
<tr>
<td>所在系:</td>
<td><input type="text" name="xi"></td>
</tr>
<tr>
<td>所在班级:</td>
<td><input type="text" name="banji"></td>
</tr>
<tr>
<td>入学年份(届):</td>
<td>
<select name="year">
<option value="1998">1998</option>
<option value="1999">1999</option>
<option value="2000">2000</option>
<option value="2001">2001</option>
<option value="2002">2002</option>
<option value="2003">2003</option>
<option value="2004">2004</option>
<option value="2005">2005</option>
<option value="2006">2006</option>
<option value="2007">2007</option>
<option value="2008">2008</option>
<option value="2009">2009</option>
<option value="2010">2010</option>
<option value="2011">2011</option>
<option value="2012">2012</option>
<option value="2013">2013</option>
<option value="2014">2014</option>
<option value="2015">2015</option>
<option value="2016">2016</option>
<option value="2017">2017</option>
<option value="2018">2018</option>
<option value="2019">2019</option>
</select>
</td>
</tr>
<tr>
<td>生源地:</td>
<td><input type="text" name="address"></td>
</tr>
<tr>
<td>
备注:
</td>
<td>
<input type="text" name="addtext" >
</td>
</tr>
<tr>
<th colspan="2">
<input type="submit" value="添加">
</th>
</tr>
</form>
</table>
</body>
</html>