Request实现简易注册登录

public class UserDao {
    /**
     * 登录方法
     * 接收service层传递用户名和密码
     * 查询数据表,获取结果集
     * 结果集封装User对象,返回业务层
     */
    public User login(String username,String password) throws SQLException {
        QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
        //拼写登录查询语句
        String sql = "select * from user where username=? and password=?";
        User user = qr.query(sql,new BeanHandler<User>(User.class),username,password);
        return user;
    }

    /**
     *  注册方法
     *  接收service传递JavaBean
     *  取出JavaBean数据,写入数据表
     */
    public void register(User user) throws SQLException {
        QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
        //拼写添加数据SQL语句
        String sql = "insert into user values(?,?,?,?,?,?,?)";
        //创建数组,存储User对象的数据
        Object[] params = {null,user.getUsername(),user.getPassword(),user.getEmail(),
                user.getName(),user.getGender(),user.getBirthday()};
        //执行SQL
        qr.update(sql,params);
    }
}

public class UserService {
    /**
     * 登录方法
     * 接收Web层传递用户名和密码
     * 参数传递dao层(数据验证)
     * 获取dao返回值,User
     * 结果,返回web层boolean
     */
    public boolean login(String username,String password){
        UserDao dao = new UserDao();
        User user = null;
        try {
            user =  dao.login(username,password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        //判断user对象,是null,登录失败返回false
        if(user==null)
            return false;
        return true;
    }
    /**
     *  注册方法
     *  接收web层传递JavaBean对象
     *  将JavaBean传递dao层
     */
    public void register(User user){
        UserDao dao = new UserDao();
        try {
            dao.register(user);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

@WebServlet(urlPatterns = "/login")
public class LoginServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        /*
         * 实现登录Servlet
         * 接收客户端提交用户名密码
         * 提交参数传递业务层
         * 接收业务层返回结果 (boolean)
         * 判断结果: true 登录成功
         *    页面重定向到首页
         *
         * 判断结果: false 登录失败
         *   错误数据存储到request域中
         *   转发回原有的登录页面
         */
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        //调用业务层方法,获取返回值,传递用户名密码
        UserService service = new UserService();
        boolean flag = service.login(username, password);
        //判断flag值,是true,登录成功,重定向首页
        if(flag){
            response.sendRedirect( request.getContextPath() );
        }else{
            //flag值是false,登录失败,错误信息存储到request域
            request.setAttribute("msg","用户名或密码错误");
            //转发回登录页面
            request.getRequestDispatcher("/login.jsp").forward(request,response);
        }
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
}

@WebServlet(urlPatterns = "/register")
public class RegisterServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        /*
         * 获取客户端提交的数据 Map
         * 数据封装到JavaBean对象中 (User)
         * 调用业务层的方法,传递User
         * 页面重定向到登录页面
         */
        request.setCharacterEncoding("utf-8");
        //获取客户端提交的数据 Map
        Map<String,String[]> map = request.getParameterMap();
        //集合中数据封装到User中
        User user = new User();
        //apache 开发工具类,简化JavaBean开发
        //BeanUtils类,静态方法 populate(JavaBean,map集合)
        try {
            BeanUtils.populate(user, map);
        }catch (Exception ex){ex.printStackTrace();}
        //调用业务层方法,传递JavaBean,完成注册
        UserService service = new UserService();
        service.register(user);
        //注册完成,页面到达登录页面,cdx
        response.sendRedirect( request.getContextPath()+"/login.jsp" );
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
}

    private int uid;
    private String password;
    private String email;
    private String username;
    private String name;
    private String gender;
    private String birthday;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class C3P0Utils {
    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
    public static DataSource getDataSource(){
        return dataSource;
    }
    public static Connection getConnection() throws SQLException{
        return dataSource.getConnection();
    }
    public static void close(ResultSet rs,Statement stat,Connection con){
        if(rs!=null)
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        if(stat!=null)
             try{
                 stat.close();
             }catch(Exception ex){}
            if(con!=null)
                try{
                     con.close();
                 }catch(Exception ex){}
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <default-config>
        <!-- 
             property标签,配置数据库连接四大信息 
             name属性,要配置什么,标签体,配置的实际内容
        -->
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/web04</property>
        <property name="user">root</property>
        <property name="password">root</property>
    </default-config>
</c3p0-config>