java前后端结合练习

package com.nnxy.dao;

import com.nnxy.entity.Product;
import com.nnxy.utlis.DruidUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import java.sql.SQLException;
import java.util.List;

public class ProductDao {
    //查询所有商品
    private QueryRunner  qr= new QueryRunner(DruidUtils.dataSource);
    public List findAllProduct() throws SQLException {
        String sql = "select * from product";
        List productList = qr.query(sql, new BeanListHandler(Product.class));
        return productList;
    }

    public int addProduct(String id,String name,String rice,String desc) throws SQLException {
        String sql = "insert into product values (?,?,?,?,0,1)";
        int update = qr.update(sql, id, name, rice, desc);
        return update;
    }

    public Product selectPname(String pname) throws SQLException {
        String sql = "select * from product where pname = ?";
        Product product = qr.query(sql, new BeanHandler(Product.class), pname);
        return product;
    }
}

package com.nnxy.web;

import com.nnxy.dao.ProductDao;
import com.nnxy.entity.Product;

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.PrintWriter;
import java.sql.SQLException;
import java.util.List;

@WebServlet(name = "findProductServlet",urlPatterns = "https://blog.csdn.net/findProductServlet")
public class FindProductServlet extends HttpServlet{
    //由于 我们需要访问 ProductDao 的方法 ， 所以将其作为 成员变量
    private ProductDao productDao = new ProductDao();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        try {
            //执行查询所有商品的操作
            List allProduct = productDao.findAllProduct();
            // 将allProduct 写出到页面上
            resp.setContentType("text/html;charset=utf-8");

            PrintWriter writer = resp.getWriter();
            writer.println("");
            for (Product p :
                    allProduct) {
                writer.println("");
            }
            writer.println("
"+p.getPname()+"
"+p.getPrice()+"
"+p.getPdesc()+"
");
            writer.println("n新增商品n" +
                    "查询指定商品n" +
                    "返回主页");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

package com.nnxy.web;

import com.nnxy.dao.ProductDao;
import com.nnxy.entity.Product;

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.PrintWriter;
import java.sql.SQLException;

@WebServlet(name = "selectProductServlet", urlPatterns = "/select_product")
public class SelectProductServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 设置请求信息编码格式为UTF-8
        req.setCharacterEncoding("utf-8");
        ProductDao productDao = new ProductDao();
        resp.setContentType("text/html;charset=utf-8");//设置网页编码 防止乱码
        PrintWriter writer = resp.getWriter();
        try {
            String pname = req.getParameter("pname");
            Product p = productDao.selectPname(pname);
            writer.println("");
            writer.println("");
            writer.println("");
            writer.println("
商品名称
商品价格
商品描述
" + p.getPname() + "
" + p.getPrice() + "
" + p.getPdesc() + "
");
            writer.println("返回主页n" +
                    "新增商品");
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            writer.close();
        }

    }
}

package com.nnxy.web;

import com.nnxy.dao.ProductDao;

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.PrintWriter;
import java.sql.SQLException;

@WebServlet(name = "updateProductServlet", urlPatterns = "/add_product")
public class UpdateProductServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 设置请求信息编码格式为UTF-8
        req.setCharacterEncoding("utf-8");
        ProductDao productDao = new ProductDao();
        resp.setContentType("text/html;charset=utf-8");//设置编码要在开启写入流操作之前进行
        PrintWriter writer = resp.getWriter();
        try {
            String addid = req.getParameter("addid");
            String addname = req.getParameter("addname");
            String addrice = req.getParameter("addrice");
            String adddesc = req.getParameter("adddesc");

            int i = productDao.addProduct(addid, addname, addrice, adddesc);
            if (i > 0) {
                System.out.println("新增" + addname + "商品成功！");
                writer.println("");
                resp.sendRedirect("https://blog.csdn.net/findProductServlet");
            }
        } catch (SQLException e) {
            e.printStackTrace();
            System.out.println("新增商品失败！");
            writer.println("");
            resp.sendRedirect("https://blog.csdn.net/weixin_48322694/article/details/add.html");
        } finally {
            writer.close();
        }
    }
}

    
    



    
商品id:

    
商品名称：

    
商品价格：

    
商品描述：

    

    
    


查询所有商品信息
新增商品
查询指定商品
返回主页

    
    



    
商品名称