JavaWeb连接数据库实现简单注册和登录功能
后台
一、首先要建包
划分包，不同的包放不同的类
controller,dao,domain,file,service,utils,validate
二、不同包的使用
controller
封装对象并获取前台数据
import org.apache.commons.beanutils.BeanUtils;
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 java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.net.URLEncoder;
import java.util.Map;
@WebServlet("/UserController")
public class UserController extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
resp.setContentType("text/html;charset=UTF-8");
User user = new User();
try {
//使用BeanUtils工具快速封装对象
BeanUtils.populate(user, req.getParameterMap());
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//获取登录的错误信息
Map error = ValidateDemo.vailDate(user);
//获取注册的错误信息
Map error1 = ValidateDemo1.vailDaet(user);
//获取到隐藏的表单，分别执行注册和登录
String str = req.getParameter("hidden");
Register register = new Register();
//注册
if ("register".equals(str)) {
if (error1.isEmpty()) {
int register1 = register.register(user);
if (register1 == 0) {
resp.sendRedirect("/web2/registerfail.jsp");
} else if (register1 == 1) {
resp.sendRedirect("/web2/registersucc.jsp");
} else if (register1 == 2) {
String test = URLEncoder.encode("用户已存在", "UTF-8");
resp.sendRedirect("/web2/register.jsp?test=" + test);
}
} else {
req.setAttribute("error1", error1);
req.getRequestDispatcher("/register.jsp").forward(req, resp);
}
}
//登录
if ("login".equals(str)) {
if (error.isEmpty()) {
Boolean bool = register.login(user);
if (bool) {
String encode = URLEncoder.encode(user.getUsername(), "UTF-8");
resp.sendRedirect("/web2/index.jsp?encode=" + encode);
} else {
req.setAttribute("error", error);
req.setAttribute("fail", "注册失败");
req.getRequestDispatcher("login.jsp").forward(req, resp);
}
} else {
req.setAttribute("error", error);
req.getRequestDispatcher("login.jsp").forward(req, resp);
}
}
}
} dao
操作数据库
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
/**
* 操作数据库
*/
public class UserDao {
/**
* 登录
* @param username
* @param password
* @return
*/
public boolean findUsernameAndPassword(String username,String password){
boolean flag = false;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = DBUtils.dbutils();
String sql = "SELECT id FROM USER WHERE username = ? AND password = ?";
ps = conn.prepareStatement(sql);
ps.setString(1,username);
ps.setString(2,password);
rs = ps.executeQuery();
while (rs.next()){
if (rs.getInt(1) > 0){
flag = true;
}
}
} catch (SQLException e) {
e.printStackTrace();
}
DBUtils.dbClose(conn,ps,rs);
return flag;
}
/**
* 注册
* @param username
* @return
*/
public boolean findUserByName(String username){
boolean flag = false;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = DBUtils.dbutils();
String sql = "SELECT id FROM USER WHERE username = ?";
ps = conn.prepareStatement(sql);
ps.setString(1,username);
rs = ps.executeQuery();
while (rs.next()){
if (rs.getInt(1) > 0){
flag = true;
}
}
} catch (SQLException e) {
e.printStackTrace();
}
DBUtils.dbClose(conn,ps,rs);
return flag;
}
/**
* 添加用户
* @param user
* @return
*/
public int addUser(User user){
int i = 0;
Connection conn = null;
PreparedStatement ps = null;
try {
conn = DBUtils.dbutils();
String sql = "INSERT INTO USER (username,password,age,gender,hobby,address,remark) values(?,?,?,?,?,?,?)";
ps = conn.prepareStatement(sql);
ps.setString(1,user.getUsername());
ps.setString(2,user.getPassword());
ps.setInt(3,user.getAge());
ps.setString(4,user.getGender());
ps.setString(5,user.getHobby());
ps.setString(6,user.getAddress());
ps.setString(7,user.getRemark());
i = ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}
DBUtils.dbClose(conn,ps,null);
return i;
}
}file
存储文件
drive=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test_1
username=root
password=rootutils
工具类
import java.sql.*;
import java.util.Properties;
public class DBUtils {
//因为dao层有多个方法要调用所有改写为静态，减少内存
static String drive;
static String url;
static String username;
static String password;
static Connection conn;
static {
Properties p = ReadFileDome.readFile();
drive = p.getProperty("drive");
url = p.getProperty("url");
username = p.getProperty("username");
password = p.getProperty("password");
try {
Class.forName(drive);
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
}
}
/**
* 注册驱动
*/
public static Connection dbutils() {
try {
conn = DriverManager.getConnection(url,username,password);
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
/**
* 关闭资源
* @param conn
* @param ps
* @param rs
*/
public static void dbClose(Connection conn, PreparedStatement ps, ResultSet rs){
if (conn != null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (ps != null){
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (rs != null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
/**
* 使用类加载去读取文件
*/
public class ReadFileDome {
public static Properties readFile(){
InputStream is = ReadFileDome.class.getClassLoader().getResourceAsStream("com/xuexi/file/db.properties");
Properties p = new Properties();
try {
p.load(is);
} catch (IOException e) {
e.printStackTrace();
}
return p;
}
}
service
业务逻辑
import com.xuexi.dao.UserDao;
import com.xuexi.domain.User;
import java.util.List;
/**
* 业务逻辑
*/
public class Register {
//登录
public boolean login(User user){
UserDao ud = new UserDao();
boolean uap = ud.findUsernameAndPassword(user.getUsername(), user.getPassword());
return uap;
}
//注册
public int register(User user){
int num;
UserDao ud = new UserDao();
boolean userByName = ud.findUserByName(user.getUsername());
if (userByName){
num = 2;
}else {
if (!userByName){
num = 1;
ud.addUser(user);
}else {
num = 0;
}
}
return num;
}
}validate
验证表单
import java.util.HashMap;
import java.util.Map;
/**
* 登录验证
*/
public class ValidateDemo {
public static Map vailDate(User user) {
//Map集合用来收集不同的错误数据，然后在前台进行使用
Map error = new HashMap<>();
//使用正则表达式来对表单数据进行限制
//判断用户名
if (user.getUsername() == null || "".equals(user.getUsername().trim())) {
error.put("username", "用户名不能为空");
} else if (!(user.getUsername().matches("\\w{6,18}"))) {
error.put("username", "用户名不合法");
}
//判断密码
if (user.getPassword() == null || "".equals(user.getPassword().trim())) {
error.put("password", "密码不能为空");
} else if (!(user.getPassword().matches("[0-9a-zA-Z]{6,18}"))) {
error.put("password", "密码不合法");
}
//判断邮箱
if (user.getEmail() == null || "".equals(user.getEmail().trim())) {
error.put("email", "邮箱不能为空");
} else if (!(user.getEmail().matches("\\w+[@][0-9a-zA-Z]+[.][0-9a-zA-Z]+"))) {
error.put("email", "邮箱不合法");
}
//判断电话
if (user.getTell() == null || "".equals(user.getTell().trim())) {
error.put("tell", "电话不能为空");
} else if (!(user.getTell().matches("^1[0-9]{10}"))) {
error.put("tell", "电话不合法");
}
return error;
}
} import java.util.HashMap;
import java.util.Map;
/**
* 注册验证
*/
public class ValidateDemo1 {
public static Map vailDaet(User user){
//Map集合用来收集不同的错误数据，然后在前台进行使用
Map error1 = new HashMap<>();
//使用正则表达式来对表单数据进行限制
//判断用户名
if (user.getUsername() == null || "".equals(user.getUsername().trim())) {
error1.put("username", "用户名不能为空");
} else if (!(user.getUsername().matches("\\w{6,18}"))) {
error1.put("username", "用户名不合法");
}
//判断密码
if (user.getPassword() == null || "".equals(user.getPassword().trim())) {
error1.put("password", "密码不能为空");
} else if (!(user.getPassword().matches("[0-9a-zA-Z]{6,18}"))) {
error1.put("password", "密码不合法");
}
return error1;
}
} domain
实体
public class User {
private String username;
private String password;
private String gender;
private int age;
private String email;
private String tell;
private String hobby;
private String address;
private String remark;
public User(String username,String password,int age,String gender,String hobby,String address,String remark){
this.username = username;
this.password = password;
this.age = age;
this.gender = gender;
this.hobby = hobby;
this.address = address;
this.remark = remark;
}
public User(){
}
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 getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getTell() {
return tell;
}
public void setTell(String tell) {
this.tell = tell;
}
public String getHobby() {
return hobby;
}
public void setHobby(String hobby) {
this.hobby = hobby;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getRemark() {
return remark;
}
public void setRemark(String remark) {
this.remark = remark;
}
@Override
public String toString() {
return "User{" +
"username='" + username + '\'' +
", password='" + password + '\'' +
", gender='" + gender + '\'' +
", age=" + age +
", hobby='" + hobby + '\'' +
", address='" + address + '\'' +
", introduce='" + remark + '\'' +
'}';
}
}
前台
准备注册页面，登录页面，注册成功页面，注册失败页面，首页
注册页面
$Title$
<%--获取错误数据--%>
<%
HashMap error1 = (HashMap) request.getAttribute("error1");
String test = request.getParameter("test");
%>
<%=test == null ? "" : test%>
登录页面
Title
<%--获取错误数据--%>
<%
HashMap error = (HashMap) request.getAttribute("error");
String fail = (String )request.getAttribute("fail");
%>
注册成功页面
Title
注册成功
登录
注册失败页面
Title
注册失败
返回
首页
Title
<%
String encode = request.getParameter("encode");
%>
欢迎 <%=encode%> 登录