[JavaScript知识库]【笔记】简单的三层架构，删除数据

前端页面

<%--a标签用来跳转，并且要带上当前数据的id--%>
<a href="/brand_demo/deleteBrandServlet?id=${brand.id}">删除</a>

表现层

@WebServlet("/deleteBrandServlet")
public class deleteBrandServlet extends HttpServlet {
    private BrandService brandService = new BrandService();

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");

        String id = request.getParameter("id");
//         调用业务逻辑层删除数据，根据前端传来的id数据删除
        brandService.deleteByid(Integer.parseInt(id));
//          当数据删除后，需要通过重定向到数据库查询表现层
//          将前端页面展示的数据进行更新
        response.sendRedirect(request.getContextPath() + "/selectAllServlet");

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

业务逻辑层

public class BrandService {
//      业务逻辑层操作数据库删除数据
    public void deleteByid(Integer id) {
        SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
        mapper.deleteByid(id);
    }
}

数据访问层

public interface BrandMapper {
//      通过id删除数据
    void deleteByid(Integer id);
}

数据库操作

<?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.cyf.mapper.BrandMapper">
<resultMap id="brand" type="com.cyf.pojo.Brand">
    <result column="brand_name" property="brandName"/>
    <result column="company_name" property="companyName"/>
</resultMap>
    <delete id="deleteByid">
        delete from tb_brand where id = #{id}
    </delete>
</mapper>