个人笔记maven web项目使用mybatis代理模式实现用户登录与注册

pom文件:

 
    
      jakarta.servlet
      jakarta.servlet-api
      5.0.0
      provided
    
    
      commons-io
      commons-io
      2.6
    
    
      org.mybatis
      mybatis
      3.5.11
    
    
      mysql
      mysql-connector-java
      8.0.31
    
  
  

接口:

public interface UserMapper {
    @Select("select * from tb_user where username = #{username} and 密码英文 = #{password}")
    User select(@Param("username") String username,@Param("password") String password);

    @Select("select * from tb_user where username = #{username}")
    User selectByUsername(String username);
//添加
    @Insert("insert into tb_user values(null,#{username},#{password})")
    void add(User user);
}

接口对应的接口,一模一样的名字.xml:

mybatis-config.xml:

---------------------------------------------------------------------------------------------------------------------------------

实列类:

public class User {

    private Integer id;
    private String username;
    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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 + '\'' +
                ", 密码英文='" + password + '\'' +
                '}';
    }
}

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//代码优化(工具类)
public class SqlSessionFactoryUtils {
    private static final SqlSessionFactory sqlSessionFactory;
    static{
        //静态代码块随着类的加载而自动执行,且只执行一次
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    public static SqlSessionFactory getSqlSessionFactory(){
        return sqlSessionFactory;
    }
}

-----------------------------------------------------------------------------------------------------------------------------

登录页面代码:

@WebServlet("/loginServlet")
public class loginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受用户名和密码
        String username = request.getParameter("username");
        String 密码英文 = request.getParameter("password");
        //2.调用Mybatis完成查询
        //2.1获取SqlSessionFactory对象
        SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
        //2.2获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //2.3获取Mapper
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        //2.4调用方法
        User user = userMapper.select(username, password);
        //2.5释放资源
        sqlSession.close();
        //获取字符输出流,并设置content type
        response.setContentType("text/html;charset=utf-8");
        PrintWriter writer = response.getWriter();
        //3.判断user是否为null
        if (user !=null){
            //登录成功
            writer.write("登录成功");
        }else {
            //登录失败
            writer.write("登录失败");
        }
    }
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }
}

注册代码:

@WebServlet("/registerServlet")
public class registerServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受用户数据
        String username = request.getParameter("username");
        String 密码英文 = request.getParameter("password");
        //封装用户对象
        User user = new User();
        user.setUsername(username);
        user.setPassword(password);
        //2.调用mapper 根据用户名查询用户对象
        //2.1获取SqlSessionFactory对象
        SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
        //2.2获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //2.3获取Mapper
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        //2.4调用方法
        User u = userMapper.selectByUsername(username);
        //用户名存在,给出提示信息
        //获取字符输出流,并设置content type
        response.setContentType("text/html;charset=utf-8");
        PrintWriter writer = response.getWriter();
        //3.判断用户对象是否为null
        if (u==null){
            //用户名不存在
            userMapper.add(user);
            //提交事务
            sqlSession.commit();
            writer.write("注册成功");
            //释放资源
            sqlSession.close();
        }else {
            writer.write("用户名以及存在");
        }
    }
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }
}