关于对Web的增删改操作，要缕清思路：

一：项目框架搭建

要用到的，Servlet、El与JSTL表达式、项目的基本框架搭建（就是java经典三层框架）：

① 表述层WEB层： 包含JSP和Servlet，与web相关内容，负责浏览器响应和请求

② 业务逻辑层 service层  ：业务逻辑，处理try...catch

③ 数据访问层 dao层  ：对SQL数据操作

除以上三层外，还要写个实体类domain，这个实体类根据数据库的数据而定义

依赖关系：web依赖于service  依赖于 dao层

 

 

 三：实现数据库连接  在MySQL中创建所需数据库，将表建好

数据库设计 

1,：创建数据库  store_1.0

2：定义项目信息表名 product，其中pid为自增长主键，增量为1

3：在product表插入记录 做试验

连接数据库

 创建一个DBUtils  定义为 MyDBUtils

package com.oracle.tools;//创建一个工具类，定义为 MyDBUtilsimport javax.sql.DataSource;import org.apache.commons.dbcp.BasicDataSource;public class MyDBUtils {    public static final String DRIVER = "com.mysql.jdbc.Driver";    public static final String URL = "jdbc:mysql://localhost:3306/store_v1.0?useUnicode=true&characterEncoding=UTF-8";    public static final String USERNAME = "root";    public static final String PASSWORD = "123456";    /*     * 创建连接池BasicDataSource     */    public static BasicDataSource dataSource = new BasicDataSource();    //静态代码块    static {        //对连接池对象 进行基本的配置        dataSource.setDriverClassName(DRIVER); // 这是要连接的数据库的驱动        dataSource.setUrl(URL); //指定要连接的数据库地址        dataSource.setUsername(USERNAME); //指定要连接数据的用户名        dataSource.setPassword(PASSWORD); //指定要连接数据的密码    }    /*     * 返回连接池对象     */    public static DataSource getDataSource(){        return dataSource;    }}

四：建立实体类

在domain层下创建一个实体类  product 并封装

package com.oracle.domain;public class Product {    private String pid;    private String pname;    private Double market_price;    private Double shop_price;    private String pimage;    private String pdate;    private Integer is_hot;    private String pdesc;    private Integer pflag;    private String cid;    public String getPid() {        return pid;    }    public void setPid(String pid) {        this.pid = pid;    }    public String getPname() {        return pname;    }    public void setPname(String pname) {        this.pname = pname;    }    public Double getMarket_price() {        return market_price;    }    public void setMarket_price(Double market_price) {        this.market_price = market_price;    }    public Double getShop_price() {        return shop_price;    }    public void setShop_price(Double shop_price) {        this.shop_price = shop_price;    }    public String getPimage() {        return pimage;    }    public void setPimage(String pimage) {        this.pimage = pimage;    }    public String getPdate() {        return pdate;    }    public void setPdate(String pdate) {        this.pdate = pdate;    }    public Integer getIs_hot() {        return is_hot;    }    public void setIs_hot(Integer is_hot) {        this.is_hot = is_hot;    }    public String getPdesc() {        return pdesc;    }    public void setPdesc(String pdesc) {        this.pdesc = pdesc;    }    public Integer getPflag() {        return pflag;    }    public void setPflag(Integer pflag) {        this.pflag = pflag;    }    public String getCid() {        return cid;    }    public void setCid(String cid) {        this.cid = cid;    }    @Override    public String toString() {        return "Product [pid=" + pid + ", pname=" + pname + ", market_price=" + market_price + ", shop_price="                + shop_price + ", pimage=" + pimage + ", pdate=" + pdate + ", is_hot=" + is_hot + ", pdesc=" + pdesc                + ", pflag=" + pflag + ", cid=" + cid + "]";    }    }

五：实现增删改

在web包下创建AddProductServlet

注意：一个Servlet对应一个功能 ，实现几个功能就要建几个Servlet

package com.oracle.web;//增import java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Map;import java.util.UUID;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.beanutils.BeanUtils;import com.oracle.domain.Product;import com.oracle.service.ProductService;public class AddProductServlet extends HttpServlet {    private ProductService productService=new ProductService();    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        //解决乱码        request.setCharacterEncoding("UTF-8");        //获取所有参数Map        Map
     
       map=request.getParameterMap();        //创建Product对象        Product product=new Product();        //用BeanUtils进行封装        try {            BeanUtils.populate(product,map);        } catch (IllegalAccessException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (InvocationTargetException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        //设置pid        product.setPid(UUID.randomUUID().toString());        //设置pdate        Date date=new Date();        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM--dd HH:mm:ss");        String d=sdf.format(date);        product.setPdate(d);        //调用Service层方法        productService.add(product);        //重定向        response.sendRedirect(request.getContextPath()+"/AdminProductListServlet");    }    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }}
     

package com.oracle.web;//改import java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.beanutils.BeanUtils;import com.oracle.domain.Product;import com.oracle.service.ProductService;public class AdminEditProductServlet extends HttpServlet {    private ProductService productService = new ProductService();    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // 解决乱码        request.setCharacterEncoding("utf-8");        // 从前台获取所有参数Map        Map
     
       map = request.getParameterMap();        // 创建Product对象        Product product = new Product();        // 用BeanUtils进行封装        try {            BeanUtils.populate(product, map);        } catch (IllegalAccessException | InvocationTargetException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        // 调用Service方法        productService.edit(product);        // 重定向        response.sendRedirect(request.getContextPath() + "/AdminProductListServlet");    }    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }}
     

package com.oracle.web;//删import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.oracle.service.ProductService;public class DeleteProductServlet extends HttpServlet {    private ProductService productService = new ProductService();    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // 获取pid        String pid = request.getParameter("pid");        // 调用service        productService.delete(pid);        // 重定向        response.sendRedirect(request.getContextPath() + "/AdminProductListServlet");    }    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }}

 六：实现servlet和对应jsp（html）页面

Servlet有两种创建方式：

1.手工创建：自己创建java类，实现Servlet具体内容，需要去web_INF下的web.xml配置Servlet

2.程序创建：在我们创建Servlet时，程序自动配置好web.xml

创建Dao层 ProductDao

package com.oracle.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import org.apache.commons.dbutils.QueryRunner;import org.apache.commons.dbutils.handlers.BeanHandler;import org.apache.commons.dbutils.handlers.BeanListHandler;import com.oracle.domain.Product;import com.oracle.tools.JDBCUtils;import com.oracle.tools.MyDBUtils;public class ProductDao {//    查询所有商品     public List
     
       getALL() throws SQLException{/*//        获得连接        Connection conn=JDBCUtils.getConn();        String sql="select * from product";        PreparedStatement pst=conn.prepareStatement(sql);        ResultSet rs=pst.executeQuery();//        处理结果集        ArrayList
      
        arr=new ArrayList
       
        ();        while(rs.next()){   //rs.取行的值              Product pro=new Product();            pro.setPid(rs.getString("pid"));            pro.setPname(rs.getString("pname"));            pro.setMarket_price(rs.getDouble("market_price"));            pro.setIs_hot(rs.getInt("is_hot"));            pro.setPdate(rs.getString("pdate"));            pro.setPimage(rs.getString("pimage"));            pro.setPdesc(rs.getString("pdesc"));            pro.setPflag(rs.getInt("pflag"));            pro.setCid(rs.getString("cid"));            arr.add(pro);                    }        return arr;*///        创建QueryRunner对象        QueryRunner qr=new QueryRunner(MyDBUtils.getDataSource());        String sql="select * from product";        List
        
          arr=qr.query(sql,new BeanListHandler
         
          (Product.class));        return arr;            }//    添加商品    public void add(Product product) throws SQLException{//        创建Queryrunner对象        QueryRunner qr=new QueryRunner(MyDBUtils.getDataSource());//获得连接池对象        String sql="insert into product(pid,pname,market_price,shop_price,pdate,pdesc,is_hot,cid) values(?,?,?,?,?,?,?,?)";//        下面获取一定注意要按上面的字符串顺序来         Object[] obj={product.getPid(),product.getPname(),product.getMarket_price(),product.getShop_price(),product.getPdate(),product.getPdesc(),product.getIs_hot(),product.getCid()};//        执行SQL        qr.update(sql,obj);            }//    根据pid查询商品    public Product getProductById(String pid) throws SQLException{        QueryRunner qr=new QueryRunner(MyDBUtils.getDataSource());        String sql="select *from product where pid=?";        Product product=qr.query(sql, new BeanHandler
          
           (Product.class),pid); return product; }// 根据pid修改商品 public void edit(Product product) throws SQLException{ QueryRunner qr=new QueryRunner(MyDBUtils.getDataSource()); String sql="update product set pname=?,market_price=?,shop_price=?,pdesc=?,is_hot=?,cid=? where pid=?"; Object[] obj={product.getPname(),product.getMarket_price(),product.getShop_price(),product.getPdesc(),product.getIs_hot(),product.getCid(),product.getPid()}; qr.update(sql,obj); }// 根据pid删除商品 public void delete(String pid) throws SQLException{ QueryRunner qr=new QueryRunner(MyDBUtils.getDataSource()); String sql="delete from product where pid=?"; qr.update(sql,pid); }}
          
         
        
       
      
     

创建 ProductService

package com.oracle.service;import java.sql.SQLException;import java.util.List;import com.oracle.dao.ProductDao;import com.oracle.domain.Product;public class ProductService {    private ProductDao productDao=new ProductDao();//    查询所有商品    public List
     
       getAll(){        List
      
        arr=null;        try {            arr=productDao.getALL();        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return arr;        }//    添加商品    public void add(Product product){        try {            productDao.add(product);        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }//    根据pid查询商品    public Product getProductById(String pid){        Product product=null;        try {            product=productDao.getProductById(pid);        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return product;    }//    根据pid修改商品    public void edit(Product product){        try {            productDao.edit(product);        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }//    根据pid删除商品    public void delete(String pid){        try {            productDao.delete(pid);        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}
      
     

 

package com.oracle.web;// 查import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.oracle.domain.Product;import com.oracle.service.ProductService;public class AdminProductListServlet extends HttpServlet {    // 后台的商品列表页面    private ProductService productService = new ProductService();    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // 获取商品列表        List
     
       list = productService.getAll();        // 向域中存list        request.setAttribute("ProductList", list);        // 请求转发        request.getRequestDispatcher("/admin/product/list.jsp").forward(request, response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        doGet(request, response);    }}