技術(shù)框架說明
前端技術(shù):
- HTML:用于創(chuàng)建網(wǎng)頁結(jié)構(gòu)和內(nèi)容的標(biāo)記語言
- CSS:用于美化和樣式化網(wǎng)頁的樣式表語言。
- JavaScript:用于實(shí)現(xiàn)網(wǎng)頁的交互和動態(tài)效果
后端技術(shù):
- Java:作為主要的后端編程語言，用于編寫服務(wù)器端的邏輯代碼
- Servlet: Java Web 技術(shù)，用于處理客戶端請求和生成響應(yīng)。
- MyBatis:Java的持久層框架，用于數(shù)據(jù)庫操作和對象關(guān)系映射
- 數(shù)據(jù)庫:用于存儲和管理數(shù)據(jù)的技術(shù)，可以是關(guān)系型數(shù)據(jù)庫(如MySQL、Oracle) 或非關(guān)系型數(shù)據(jù)庫 (如MongoDB)。
登錄案例
1.需求分析
需求分析
- 用戶在登錄頁面輸入用戶名和密碼，提交請求給LoginServlet
- 在LoginServlet中接收請求和數(shù)據(jù)[用戶名和密碼]
- 在LoginServlt中通過Mybatis實(shí)現(xiàn)調(diào)用UserMapper來根據(jù)用戶名和密碼查詢數(shù)據(jù)庫表
- 將查詢的結(jié)果封裝到User對象中進(jìn)行返回
- 在LoginServlet中判斷返回的User對象是否為null
- 如果為nul，說明根據(jù)用戶名和密碼沒有查詢到用戶，則登錄失敗，返回"登錄失敗"數(shù)據(jù)給前端
- 如果不為null,則說明用戶存在并且密碼正確，則登錄成功，返回"登錄成功"數(shù)據(jù)給前端
2.環(huán)境準(zhǔn)備
2.1 前端頁面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>login</title>
<link href="css/login.css" rel="stylesheet">
</head>
<body>
<div id="loginDiv">
<form action="" id="form">
<h1 id="loginMsg">LOGIN IN</h1>
<p>Username:<input id="username" name="username" type="text"></p>
<p>Password:<input id="password" name="password" type="password"></p>
<div id="subDiv">
<input type="submit" class="button" value="login up">
<input type="reset" class="button" value="reset">
<a href="register.html">沒有賬號？點(diǎn)擊注冊</a>
</div>
</form>
</div>
</body>
</html>
2.2 創(chuàng)建數(shù)據(jù)表及對應(yīng)的實(shí)體類
創(chuàng)建數(shù)據(jù)庫以及tb_user表 ，創(chuàng)建User實(shí)體類
-- 創(chuàng)建用戶表
CREATE TABLE tb_user(
id int primary key auto_increment,
username varchar(20) unique,
password varchar(32)
);
-- 添加數(shù)據(jù)
INSERT INTO tb_user(username,password) values('zhangsan','123'),('lisi','234');
SELECT * FROM tb_user;
創(chuàng)建用戶表
package com.itheima.pojo;
//用戶實(shí)體類
public class User {
private int id;
private String username;
private String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
2.3 導(dǎo)入mybatis坐標(biāo)，MySQL坐標(biāo)
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.32</version>
</dependency>
2.4 配置文件及接口
mybatis-config.xml核心配置文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!--起別名-->
<typeAliases>
<package name="com.itheima.pojo"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql:///db1?useSSL=false&useServerPrepStmts=true"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<!--掃描mapper-->
<package name="com.itheima.mapper"/>
</mappers>
</configuration>
UserMapper.xml映射文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.UserMapper">
</mapper>
UserMapper接口
package com.itheima.mapper;
public interface UserMapper {
}
3. 用戶名密碼校驗(yàn)
輸入用戶名和密碼再到數(shù)據(jù)庫中進(jìn)行查詢
步驟：
- 編寫接口：Mapper接口
- 編寫sql語句：sql映射文件
- 執(zhí)行方法，測試
方法1：XML 或注解方式配置 SQL 查詢語句
public interface UserMapper {
//使用 @Param 注解來指定參數(shù)的名稱
User selectByNaPa(@Param("username") String username,@Param("password") String password);
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--
namespace:名稱空間
-->
<mapper namespace="com.itheima.mapper.UserMapper">
<select id="selectByNaPa" resultType="com.itheima.pojo.User">
SELECT * FROM tb_user WHERE username = #{username} AND password = #{password};
</select>
</mapper>
package com.itheima;
import com.itheima.mapper.UserMapper;
import com.itheima.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
public class LodeTest1 {
public static void main(String[] args) throws IOException {
//1.傳入?yún)?shù)
String un = "zhangsan";
String pw = "123";
//2.加載核心文件，獲取SqlSessionFactory
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//3. 獲取對應(yīng)的sqlsession，執(zhí)行sql
SqlSession sqlSession = sqlSessionFactory.openSession();
//4. 執(zhí)行sql
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.selectByNaPa(un, pw);
System.out.println(user);
//5.釋放資源
sqlSession.close();
}
}
方法2：使用 @Select 注解來聲明一個(gè)查詢方法
代碼片段使用注解方式，將 SQL 查詢語句直接寫在方法上，不需要額外的 XML 配置文件。
package com.itheima.mapper;
import com.itheima.pojo.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
public interface UserMapper {
@Select("select * from tb_user where username = #{username} and password = #{password}}}")
User selectByNaPa(@Param("username") String username, @Param("password") String password);
}
使用標(biāo)簽
package com.itheima.mapper;
import com.itheima.pojo.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
public interface UserMapper {
@Select("select * from tb_user where username = #{username} and password = #{password}}}")
User selectByNaPa(@Param("username") String username, @Param("password") String password);
}
4. 前端配置
將會在用戶提交時(shí)將數(shù)據(jù)發(fā)送到 “/loginServlet” 的服務(wù)器端處理程序，并使用 POST 方法發(fā)送數(shù)據(jù)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>login</title>
<link href="css/login.css" rel="stylesheet">
</head>
<body>
<div id="loginDiv">
<form action="/loginServlet" method="post" id="form">
<h1 id="loginMsg">LOGIN IN</h1>
<p>Username:<input id="username" name="username" type="text"></p>
<p>Password:<input id="password" name="password" type="password"></p>
<div id="subDiv">
<input type="submit" class="button" value="login up">
<input type="reset" class="button" value="reset">
<a href="register.html">沒有賬號？點(diǎn)擊注冊</a>
</div>
</form>
</div>
</body>
</html>
5.Servlet編寫
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// super.doGet(req, resp);
//1. 接受用戶名和密碼
String username = req.getParameter("username");
String password = req.getParameter("password");
//2.調(diào)用mybatis完成查詢
//2.1獲取sqlsessionFactory
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//2.2 獲取sqlsession
SqlSession sqlSession = sqlSessionFactory.openSession();
//2.3 執(zhí)行sql
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.selectByNaPa(username, password);
System.out.println(user);
//2.4 釋放資源
sqlSession.close();
//獲取響應(yīng)數(shù)據(jù)
resp.setContentType("text/html;charset = utf-8");
PrintWriter writer = resp.getWriter();
//3. 判斷user是否為null
if (user != null){
//登錄成功
writer.write("登錄成功");
}else {
//失敗
writer.write("登錄失敗");
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// super.doPost(req, resp);
this.doGet(req, resp);
}
}
注冊案例
1.需求分析
需求分析
- 用戶在注冊頁面輸入用戶名和密碼，提交請求給RegisterServlet
- 在RegisterServlet中接收請求和數(shù)據(jù)[用戶名和密碼]
- 在RegisterServlet中通過Mybatis實(shí)現(xiàn)調(diào)用UserMapper來根據(jù)用戶名查詢數(shù)據(jù)庫表
- 將查詢的結(jié)果封裝到User對象中進(jìn)行返回
- 在RegisterServlet中判斷返回的User對象是否為null
- 如果為nul，說明根據(jù)用戶名可用，則調(diào)用UserMapper來實(shí)現(xiàn)添加用戶
- 如果不為null,則說明用戶不可以，返回"用戶名已存在"數(shù)據(jù)給前端
2.配置用戶接口
//添加用戶
@Insert("insert into tb_user values(null,#{username},#{password})")
void add(User user);
3. 測試添加用戶
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class InsertTest {
public static void main(String[] args) throws IOException {
//1.傳入?yún)?shù)
String un = "tudou";
String pw = "000";
User user1 = new User();
user1.setUsername(un);
user1.setPassword(pw);
//2.加載核心文件，獲取SqlSessionFactory
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//3. 獲取對應(yīng)的sqlsession，執(zhí)行sql
SqlSession sqlSession = sqlSessionFactory.openSession();
//4. 執(zhí)行sql
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.add(user1);
sqlSession.commit();
//查看全部看是否添加成功‘
List<User> users = userMapper.selectAll();
System.out.println(users);
//5.釋放資源
sqlSession.close();
}
}
4. 前端配置
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>歡迎注冊</title>
<link href="css/register.css" rel="stylesheet">
</head>
<body>
<div class="form-div">
<div class="reg-content">
<h1>歡迎注冊</h1>
<span>已有帳號？</span> <a href="login.html">登錄</a>
</div>
<form id="reg-form" action="/registerServlet" method="post">
<table>
<tr>
<td>用戶名</td>
<td class="inputs">
<input name="username" type="text" id="username">
<br>
<span id="username_err" class="err_msg" style="display: none">用戶名不太受歡迎</span>
</td>
</tr>
<tr>
<td>密碼</td>
<td class="inputs">
<input name="password" type="password" id="password">
<br>
<span id="password_err" class="err_msg" style="display: none">密碼格式有誤</span>
</td>
</tr>
</table>
<div class="buttons">
<input value="注 冊" type="submit" id="reg_btn">
</div>
<br class="clear">
</form>
</div>
</body>
</html>
5. servlet編寫
package com.itheima.web;
import com.itheima.mapper.UserMapper;
import com.itheima.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
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.io.InputStream;
import java.io.PrintWriter;
@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// super.doGet(req, resp);
//1. 接受用戶名和密碼
String username = req.getParameter("username");
String password = req.getParameter("password");
User user1 = new User();
user1.setUsername(username);
user1.setPassword(password);
//2.調(diào)用mybatis完成查詢
//2.1獲取sqlsessionFactory
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//2.2 獲取sqlsession
SqlSession sqlSession = sqlSessionFactory.openSession();
//2.3 執(zhí)行sql
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
//2.4 調(diào)用方法
User u = userMapper.selectByUsername(username);
//3. 判斷用戶對象釋放為null
if( u == null){
// 用戶名不存在，添加用戶
userMapper.add(user1);
// 提交事務(wù)
sqlSession.commit();
// 釋放資源
sqlSession.close();
}else {
// 用戶名存在，給出提示信息
resp.setContentType("text/html;charset=utf-8");
resp.getWriter().write("用戶名已存在");
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// super.doPost(req, resp);
this.doGet(req, resp);
}
}
注冊用戶
文章來源：http://www.zghlxwxcb.cn/news/detail-654007.html
輸入已經(jīng)存在的用戶進(jìn)行注冊
> >
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