完成删除

这不是有手就行？
这个当时看的视频黑马没有说这个，于是自己补上了。
先定义一个删除的方法

   @Delete("delete  from tb_brand where id = #{id}")
    void delete(int id);

回顾一下工具类和Service层

package com.jgdabc.util;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

public class SqlSessionFactoryUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static {
        //静态代码块会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) {
            e.printStackTrace();
        }
    }


    public static SqlSessionFactory getSqlSessionFactory(){
        return sqlSessionFactory;
    }
}

package com.jgdabc.service;

import com.jgdabc.mapper.BrandMapper;
import com.jgdabc.pojo.Brand;
import com.jgdabc.util.SqlSessionFactoryUtils;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class BrandService {
    SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();
    public List<Brand>selectAll()
    {

        SqlSession sqlSession = factory.openSession();
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
        List<Brand> brands = mapper.selectAll();
        sqlSession.close();
        return  brands;

    }
    public void add(Brand brand)
    {
        SqlSession sqlSession = factory.openSession();
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
        mapper.add(brand);
        sqlSession.commit();
        sqlSession.close();
    }
//   根据id查询
    public Brand selectById(int id)
    {

        SqlSession sqlSession = factory.openSession();
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
        Brand brand = mapper.selectById(id);
        sqlSession.close();
        return  brand;

    }
    public void update(Brand brand)
    {
        SqlSession sqlSession = factory.openSession();
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
        mapper.update(brand);
        sqlSession.commit();
        sqlSession.close();
    }
    public void delete(Integer brand)
    {
        SqlSession sqlSession = factory.openSession();
        BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
        mapper.delete(brand);
        sqlSession.commit();
        sqlSession.close();
    }

}

我们的service调用的delete方法

注意看我们展示界面的删除

好，转发到Servlet

package com.jgdabc.util.web;

import com.jgdabc.service.BrandService;

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;

@WebServlet("/selectDeleteServlet")
public class SelectDeleteServlet extends HttpServlet {
    BrandService service = new BrandService();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        BrandService brandService = new BrandService();
        String id = request.getParameter("id");
        Integer id_1 = Integer.parseInt(id);
        brandService.delete(id_1);

//        request.getRequestDispatcher("/brand.jsp").forward(request,response);
        response.sendRedirect("selectAllServlet");


    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}

这样就可以了。

我们需要再写一个删除的jsp吗？没有必要。前面的添加修改，都需要进行传参的，然后需要根据参数进行在Servlet进行操作。删除直接调用删除方法在主界面中传参，然后传到Servlet进行处理调用方法，再次回到主界面就可以了。

这样就删除成功了。