Javaweb - 实例功能（下） - 用户注册功能实现（mybatis、maven、mysql、tomcat、servlet）

流程说明

UserMapper.java

映射sql Register表单

css文件Js文件 RegisterServlet 测试运行

注意

用户填写用户名、密码等信息、点击注册按钮，提交到RegisterServlet在RegisterServlet中使用MyBatis 保存数据保存前，需要判断用户名是否已经存在：根据用户名查询数据库

编写UserMapper接口中方法，这里add方法使用mybatis，不使用注解，容易bug

package com.taotao.mapper;

import com.taotao.pojo.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

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

    
    @Select("select * from tb_user where username = #{username}")
    User selectByUsername(String username);

//    
//    @Insert("insert into tb_user values (null,#{username},#{password})")
    void add(User user);
}

编写映射UserMapper.xml文件

    
        insert into tb_user(id,username,password)
        values (null,#{username},#{password});
    

编写Register.html表单页面

	
		
		
		
	
	
		

			
Welcome Register
			

			

			
		
		
	

	*{
				margin: 0;
				padding: 0;
				border: 0px;
			}
			body{
				background-color: skyblue;
			}
			form{
				position: absolute;
				left: 50%;
				top: 50%;
				margin-left: -300px;
				margin-top: -280px;
				width: 600px;
				height: 400px;
				background-color: #ebc4c4;
				border: 1px solid;
				border-radius: 10px;
				box-shadow: 0px 0px 5px 5px rgba(0,0,0,.3);
				transition: all 1s;
				opacity: 0;
			}
			.show{
				opacity: 1;
				transform:translateY(80px)
				
			}
			.head{
				width: 100%;
				font-family: "隶书";
				text-align: center;
				font-size: 24px;
				color: #ffffff;
				margin-top: 50px;
				letter-spacing: 5px;
			}
			#user{
				position: absolute;
				top: 40%;
				left: 50%;
				margin-left: -100px;
				width: 200px;
				height: 20px;
				outline: none;
				background-color: transparent;
				border-bottom: 1px solid;
			}
			#paws{
				position: absolute;
				top: 50%;
				left: 50%;
				margin-left: -100px;
				width: 200px;
				height: 20px;
				outline: none;
				background-color: transparent;
				border-bottom: 1px solid;
			}
			#sub{
				position: absolute;
				top: 60%;
				left: 50%;
				margin-left: -60px;
				width: 120px;
				height: 35px;
				background-color: orange;
				border-radius: 8px;
			}
			#sub:hover{
				cursor: pointer;
				background-color: #87CEEB;
			}

 var from = document.querySelector('form');
		   console.log(from);
window.addEventListener('load',function(){
		from.className=('show'+' from')
})

com.taotao.web包下新建RegisterServlet.java类

package com.taotao.web;

import com.taotao.mapper.UserMapper;
import com.taotao.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;


@SuppressWarnings({"all"})
@WebServlet(urlPatterns = "/registerServlet")
public class RegisterServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.接收用户数据
        String username = req.getParameter("username");
        String password = req.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
        String resource = "mybatis.config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        //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);
        System.out.println(user);
        //设置utf-8编码格式以及识别html标签
        resp.setContentType("text/html;charset=utf-8");

        //3.判断用户对象是否为null
        if (u == null){
            //用户名不存在，添加用户
            userMapper.add(user);
            //提交事务
            sqlSession.commit();

            //释放资源
            sqlSession.close();
            resp.getWriter().write("create user successful!!");
        }else {
            //用户名存在，给出提示信息
            resp.getWriter().write("can't create the user,the user is exists");
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req, resp);
    }


}

遇到了一个注解sql参数报错，最后使用mybatis映射文件sql解决问题