商品案例
实现商品图片的上传，显示商品名称、价格 、数量、图片、描述等。可以对商品进行增改查。
导包、配置文件和工具类准备
-
导入
commons-beanutils.jar、commons-fileupload.jar、commons-io.jar、commons-logging.jar、mysql-connector-java-bin.jar放到WEB-INF/lib下。 -
数据库配置文件
ClassName=com.mysql.jdbc.Driver url=jdbc\:mysql\://localhost\:3306/example user=root password=admin -
数据库连接工具类
package utils;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;
public class JDBCUtil {
private static String driver;
private static String url;
private static String user;
private static String password;
// 静态代码块，随着类的加载而加载，只加载一次
static {
try {
Properties prop = new Properties();
// 下面这个是本机使用的就填写项目所在位置，但是我们是要部署到服务器的，所以获取WEB-INF/classes目录下的，注意要加"/"
// InputStream is = new FileInputStream("/product/src/jdbc_setting.properties");
InputStream is = JDBCUtil.class.getResourceAsStream("/jdbc_setting.properties");
// load()接收InputStream，所以向上转型
prop.load(is);
driver = prop.getProperty("ClassName");
url = prop.getProperty("url");
user = prop.getProperty("user");
password = prop.getProperty("password");
Class.forName(driver);
is.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public static Connection getConnection() {
Connection connection = null;
try {
connection = DriverManager.getConnection(url, user, password);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException("创建连接失败！");
}
return connection;
}
// 释放资源
// 参数可能为空
// 调用close要抛出异常，即使出现异常也能关闭
public void close(Connection conn, Statement state, ResultSet result) {
try {
if (result != null) {
result.close();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (state != null) {
state.close();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
写一个Bean封装商品数据
package bean;
public class Product {
private int id;
private String name;
private double price;
private int pnum;
private String descreption;
private String type;
private String imgurl;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getPnum() {
return pnum;
}
public void setPnum(int pnum) {
this.pnum = pnum;
}
public String getDescreption() {
return descreption;
}
public void setDescreption(String descreption) {
this.descreption = descreption;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getImgurl() {
return imgurl;
}
public void setImgurl(String imgurl) {
this.imgurl = imgurl;
}
@Override
public String toString() {
return "Product [id=" + id + ", name=" + name + ", price=" + price + ", pnum=" + pnum + ", descreption="
+ descreption + ", type=" + type + ", imgurl=" + imgurl + "]";
}
}
定义用户保存商品信息的接口并实现
package dao;
import java.util.List;
import bean.Product;
public interface ProductDao {
// 保存商品
void save(Product p);
// 获得所有商品
List<Product> getAllProducts();
//根据商品id获得商品对象
Product getById(int id);
//更新商品数据
void update(Product p);
}
实现上面的接口，之所以定义为接口是因为实现里面可能尽不相同。在这里主要是sql语句的不同，写成接口更加灵活。
package dao.imple;
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 bean.Product;
import dao.ProductDao;
import utils.JDBCUtil;
public class ProductDaoImple implements ProductDao {
@Override
public void save(Product p) {
// 1. 获得连接
Connection connection = JDBCUtil.getConnection();
// 2. 准备sql语句
String sql = "insert into `example`.`t_product` ("
+ "`id`,`name`,`price`,`pnum`,`descreption`,`type`,`imgurl`) " + "values "
+ "(NULL, ?, ?, ?, ?, ?, ?);";
// 3.获得PreparedStatement
PreparedStatement ps = null;
try {
ps = connection.prepareStatement(sql);
// 4. 设置参数, 1表示第一个？
ps.setString(1, p.getName());
ps.setDouble(2, p.getPrice());
ps.setInt(3, p.getPnum());
ps.setString(4, p.getDescreption());
ps.setString(5, p.getType());
ps.setString(6, p.getImgurl());
// 5. 执行sql
int rows = ps.executeUpdate();
// 这里只是新增了一行，不等于1说明添加失败
if (rows != 1) {
throw new RuntimeException("添加商品失败！");
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("添加商品失败！");
} finally {
// 关闭资源
JDBCUtil.close(connection, ps, null);
}
}
@Override
public List<Product> getAllProducts() {
List<Product> list = new ArrayList<>();
// 1. 建立连接
Connection connection = JDBCUtil.getConnection();
// 2. 准备sql语句
String sql = "select * from t_product;";
// 3. 创建PreparedStatement
PreparedStatement pStatement = null;
ResultSet rs = null;
try {
pStatement = connection.prepareStatement(sql);
// 4. 执行查询
rs = pStatement.executeQuery();
// 5. 遍历结果集
while (rs.next()) {
// 将结果集中的数据封装到Product对象中
Product p = new Product();
p.setId(rs.getInt("id"));
p.setName(rs.getString("name"));
p.setPrice(rs.getDouble("price"));
p.setPnum(rs.getInt("pnum"));
p.setDescreption(rs.getString("descreption"));
p.setType(rs.getString("type"));
p.setImgurl(rs.getString("imgurl"));
list.add(p);
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("查询商品数据失败!");
} finally {
// 6 关闭资源
JDBCUtil.close(connection, pStatement, rs);
}
// 返回产品列表
return list;
}
public Product getById(int id) {
// 1 获得连接
Connection conn = JDBCUtil.getConnection();
// 2 sql语句
String sql = "select * from t_product where id = ?;";
// 3 创建PrepareStatement
PreparedStatement ps = null;
ResultSet rs = null;
Product p = null;
try {
ps = conn.prepareStatement(sql);
// 设置参数
ps.setInt(1, id);
// 4 执行sql
rs = ps.executeQuery();
// 5 遍历结果集
if (rs.next()) {
// 将结果集中的数据封装到Product对象中
p = new Product();
p.setName(rs.getString("name"));
p.setId(rs.getInt("id"));
p.setPrice(rs.getDouble("price"));
p.setPnum(rs.getInt("pnum"));
p.setType(rs.getString("type"));
p.setImgurl(rs.getString("imgurl"));
p.setDescreption(rs.getString("descreption"));
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("根据id查询商品数据失败!");
} finally {
// 6 关闭资源
JDBCUtil.close(conn, ps, rs);
}
// 7 返回产品集合
return p;
}
// 更新产品
public void update(Product p) {
// 进行判断，edit.jsp里面只是将图片进行显示。如果不上传新的图片，imgurl为空。所以EditServlet里面应该对FileItem的大小就行判断。
// 即fileItem .getSize() > 0 才执行保存imgurl，更新数据库的图片地址。否则不会更改数据库的图片地址
boolean hasNewImg = p.getImgurl() != null;
// 1 获得连接
Connection conn = JDBCUtil.getConnection();
// 2 准备sql
String sql = "UPDATE " + "`t_product`" + " SET "
+ " `name` = ?, " + "`price` = ?," + "`pnum` = ?, "
+ "`descreption` = ?," + "`type` = ? ";
if (hasNewImg) {
sql += ",`imgurl` = ?" + " WHERE `id` = ?;";
} else {
sql += " WHERE `id` = ?;";
}
PreparedStatement ps = null;
try {
// 3 获得PrepareStatement
ps = conn.prepareStatement(sql);
// 4 设置参数
ps.setString(1, p.getName());
ps.setDouble(2, p.getPrice());
ps.setInt(3, p.getPnum());
ps.setString(4, p.getDescreption());
ps.setString(5, p.getType());
if (hasNewImg) {
ps.setString(6, p.getImgurl());
ps.setInt(7, p.getId());
} else {
ps.setInt(6, p.getId());
}
// 5 执行sql
int rowcount = ps.executeUpdate();
if (rowcount != 1) {
throw new RuntimeException("修改商品数据失败!");
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("修改商品数据失败!");
} finally {
// 6 关闭资源
JDBCUtil.close(conn, ps, null);
}
}
}
接下来是一个商品服务类，就更简单了。只是简单调用了上面实现类的save方法而已。
package service;
import java.util.List;
import bean.Product;
import dao.imple.ProductDaoImple;
public class ProductService {
ProductDaoImple productDaoImple = new ProductDaoImple();
public void save(Product p) {
productDaoImple.save(p);
}
public List<Product> getAllProducts() {
return productDaoImple.getAllProducts();
}
//根据id查询商品对象
public Product getById(int id){
return productDaoImple.getById(id);
}
public void update(Product p){
productDaoImple.update(p);
}
}
添加商品的界面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'login.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form action="/product/AddProductServlet" method="post" enctype="multipart/form-data" >
<table border="1">
<tr>
<th colspan="2" align="center" >
添加商品
</th>
</tr>
<tr>
<td>商品名称</td>
<td><input type="text" name="name" /></td>
</tr>
<tr>
<td>商品价格</td>
<td><input type="text" name="price" /></td>
</tr>
<tr>
<td>商品库存</td>
<td><input type="text" name="pnum" /></td>
</tr>
<tr>
<td>类别</td>
<td>
<select name="type">
<option value="日用百货">日用百货</option>
<option value="电子产品">电子产品</option>
<option value="零食">零食</option>
</select>
</td>
</tr>
<tr>
<td>商品图片</td>
<td><input type="file" name="img" /></td>
</tr>
<tr>
<td>商品描述</td>
<td><textarea name="descreption" cols="40" rows="10"/></textarea></td>
</tr>
<tr>
<td colspan="2" align="center" >
<input type="submit" value="添加" />
</td>
</tr>
</table>
</form>
</body>
</html>
保存到数据库
package web;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
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 org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.IOUtils;
import bean.Product;
import service.ProductService;
import utils.PathUtils;
@WebServlet("/AddProductServlet")
public class AddProductServlet extends HttpServlet {
private ProductService productService = new ProductService();
Product product = new Product();
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 1. 创建配置工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
// 2. 创建解析器
ServletFileUpload upload = new ServletFileUpload(factory);
// 用来存放表单中的键值对
Map<String, String[]> map = new HashMap<>();
// 3. 解析request
List<FileItem> fileItems = null;
try {
fileItems = upload.parseRequest(request);
// 4. 遍历FileItem
if (fileItems != null) {
for (FileItem fileItem : fileItems) {
// 是普通段
if (fileItem.isFormField()) {
// 由于是文件上传制定了enctype="multipart/form-data",
// 用下面这个方法获取不到参数。
// BeanUtils.populate(product,
// request.getParameterMap());
// 需要用FileItem的getString()才能获得键对应的值
String key = fileItem.getFieldName();
String value = fileItem.getString("UTF-8");
// 同一个name属性的值可能相同，Map不允许重复键，所以放入数组
map.put(key, new String[] { value });
// 是文件，将文件保存到项目根目录下的upload文件夹
} else {
// 获得upload文件夹路径
String uploadPath = getServletContext().getRealPath("/upload");
// 生成日期文件夹
String datePath = PathUtils.getPath(uploadPath);
// 生成文件名
String fileName = UUID.randomUUID().toString();
// 保存图片
InputStream is = fileItem.getInputStream();
FileOutputStream fos = new FileOutputStream(uploadPath + datePath + fileName);
IOUtils.copy(is, fos);
// 保存访问路径
product.setImgurl("/upload" + datePath + fileName);
// 关流
fos.close();
}
}
}
} catch (FileUploadException e) {
e.printStackTrace();
throw new RuntimeException("你的操作有误!");
}
try {
BeanUtils.populate(product, map);
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
// 保存商品到数据库
productService.save(product);
// 重定向到列表显示，先到servlet在到jsp，因为需要从servlet中从数据库取得数据
response.sendRedirect(request.getContextPath() + "/ListServlet");
}
}
上面写了一个PathUtils来获取日期文件夹的路径
package utils;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
public class PathUtils {
public static String getPath(String prefix) {
SimpleDateFormat dateFormat = new SimpleDateFormat("/yyyy/MM/dd/");
// 解析好后是 /2017/04/17/
String datePath = dateFormat.format(new Date());
// 日期文件夹的完整路径
String wholePath = prefix + datePath;
File file = new File(wholePath);
// 不存在就创建，保证AddProduct里面访问时候就已经存在
if (!file.exists()) {
file.mkdirs();
}
return datePath;
}
}
商品显示
这里只是为了学习才引入JSON，一般不这样用。
package web;
import java.io.IOException;
import java.util.List;
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 bean.Product;
import net.sf.json.JSONArray;
import service.ProductService;
@WebServlet("/ListServlet")
public class ListServlet extends HttpServlet {
private ProductService ps = new ProductService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<Product> products = ps.getAllProducts();
//2 将商品列表放入request域, 将bean直接放入，解析成json
String json = JSONArray.fromObject(products).toString();
request.setAttribute("json", json);
//3 转发到list.jsp
request.getRequestDispatcher("/WEB-INF/page/list.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
使用js动态生成表格
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body onload="fun1()" >
<h1>商品列表</h1>
<table border="1" id="one" >
</table>
<script type="text/javascript">
function fun1(){
var table = document.getElementById("one");
// 获得ListServlet所有商品的数组,eval可以把字符串当成语句来执行
var jsonArray = eval(${requestScope.json});
//遍历数组,将商品添加到页面中的列表中。for语句里面没有写自增i++是因为这里我们想要一行显示两个商品
for(var i = 0 ; i<jsonArray.length;){
//创建tr对象
var tr = document.createElement("tr");
//取出一个商品
var product1 = jsonArray[i++];
//创建td对象
var td = document.createElement("td");
// 点击超链接跳转到编辑商品属性的Servlet，同时传过去了参数name
td.innerHTML="![](/product"+product1["imgurl"]+")<br><a href='/product/ToEditServlet?id="+product1["id"]+"' >"+product1["name"]+"</a><br>"+product1["price"]+"元";
//将td添加到tr中
tr.appendChild(td);
//判断,是否还有下一个商品，商品个数为奇数时候不会执行if
if(i < jsonArray.length){
//取出一个商品
var product2 = jsonArray[i++];
//创建td对象
var td2 = document.createElement("td");
td2.innerHTML="![](/product"+product2["imgurl"]+")<br><a href='/product/ToEditServlet?id="+product2["id"]+"' >"+product2["name"]+"</a><br>"+product2["price"]+"元";
//将td添加到tr中
tr.appendChild(td2);
}
//tr添加到表格中
table.appendChild(tr);
}
}
</script>
</body>
</html>
看一下，文字和图片都会瞎写的
点击添加，跳转到商品列表
商品修改
点击商品标题的超链接，跳转道ToEditServlet，并且携带了参数id
package web;
import java.io.IOException;
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 bean.Product;
import service.ProductService;
/**
* Servlet implementation class ToEditServlet
*/
@WebServlet("/ToEditServlet")
public class ToEditServlet extends HttpServlet {
private ProductService pService = new ProductService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// list.jsp里面<a href='/product/ToEditServlet?id="+product1["id"]传来的id参数
String tagId = request.getParameter("id");
// 根据id获得具体的商品
Product product = pService.getById(Integer.parseInt(tagId));
// 设置属性转发到显示页面
request.setAttribute("product", product);
request.getRequestDispatcher("/WEB-INF/page/edit.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
跳转到修改商品的jsp页面，这个表格和谈价商品的表格非常类似。
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'edit.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form action="/product/EditServlet" method="post" enctype="multipart/form-data" >
<table border="1" >
<tr>
<th colspan="2" align="center" >
修改商品
</th>
</tr>
<tr>
<td>商品名称:</td>
<td><input type="text" name="name" value="${requestScope.product.name}" /></td>
</tr>
<tr>
<td>商品价格:</td>
<td><input type="text" name="price" value="${requestScope.product.price}" /></td>
</tr>
<tr>
<td>库存:</td>
<td><input type="text" name="pnum" value="${requestScope.product.pnum}" /></td>
</tr>
<tr>
<td>类别:</td>
<td>
<%--原来数据库里类别是什么，就让哪个默认选中 --%>
<select name="type" >
<option value="日用百货" ${requestScope.product.type == "日用百货" ? "selected":"" } >日用百货</option>
<option value="电子产品" ${requestScope.product.type == "电子产品" ? "selected":"" } >电子产品</option>
<option value="零食" ${requestScope.product.type == "零食" ? "selected":"" } >零食</option>
</select>
</td>
</tr>
<tr>
<td>商品图片:</td>
<td>
<input type="file" name="img" />
</td>
</tr>
<tr>
<td>商品描述:</td>
<td><textarea name="description" cols="50" rows="10" >
${requestScope.product.descreption}
</textarea></td>
</tr>
<tr>
<td colspan="2" align="center" >
<input type="submit" value="修改" />
</td>
</tr>
</table>
<%-- 不修改id故隐藏,但是要提交 --%>
<input type="hidden" name="id" value="${requestScope.product.id}" />
</form>
</body>
</html>
由EditServlet更新数据库，并重定向到ListServlet重新从数据库取得数据并显示。注意：edit.jsp只是显示了未修改的图片而已，如果不修改，即没有选择文件上传。文件段的fileitem内容就是空的，保存imgurl时就为空，一更新数据导致数据库中原来的图片也丢失。所以需要判断fileItem.getSize() > 0保证确实上传了文件才更新图片imgurl，否则不更新imgurl
package web;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
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 org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.IOUtils;
import bean.Product;
import service.ProductService;
import utils.PathUtils;
@WebServlet("/EditServlet")
public class EditServlet extends HttpServlet {
// 由于修改商品使用的表格和添加商品的表格差不多，这里基本可以用AddProductServlet的代码。只是最后是update
private ProductService productService = new ProductService();
Product product = new Product();
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 1. 创建配置工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
// 2. 创建解析器
ServletFileUpload upload = new ServletFileUpload(factory);
// 用来存放表单中的键值对
Map<String, String[]> map = new HashMap<>();
// 3. 解析request
List<FileItem> fileItems = null;
try {
fileItems = upload.parseRequest(request);
// 4. 遍历FileItem
if (fileItems != null) {
for (FileItem fileItem : fileItems) {
// 是普通段
if (fileItem.isFormField()) {
// 由于是文件上传制定了enctype="multipart/form-data",
// 用下面这个方法获取不到参数。
// BeanUtils.populate(product,
// request.getParameterMap());
// 需要用FileItem的getString()才能获得键对应的值
String key = fileItem.getFieldName();
String value = fileItem.getString("UTF-8");
// 同一个name属性的值可能相同，Map不允许重复键，所以放入数组
map.put(key, new String[] { value });
// 是文件，将文件保存到项目根目录下的upload文件夹
} else {
// 上传的文件不为空才保存imgurl，否则为空保存为null，更新数据库图片丢失
if (fileItem.getSize() > 0) {
// 获得upload文件夹路径
String uploadPath = getServletContext().getRealPath("/upload");
// 生成日期文件夹
String datePath = PathUtils.getPath(uploadPath);
// 生成文件名
String fileName = UUID.randomUUID().toString();
// 保存图片
InputStream is = fileItem.getInputStream();
FileOutputStream fos = new FileOutputStream(uploadPath + datePath + fileName);
IOUtils.copy(is, fos);
// 保存访问路径
product.setImgurl("/upload" + datePath + fileName);
// 关流
fos.close();
}
}
}
}
} catch (FileUploadException e) {
e.printStackTrace();
throw new RuntimeException("你的操作有误!");
}
try {
BeanUtils.populate(product, map);
} catch (IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
// 保存商品到数据库
productService.update(product);
// 重定向到列表显示，先到servlet在到jsp，因为需要从servlet中从数据库取得数据
response.sendRedirect(request.getContextPath() + "/ListServlet");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
看下修改页面，修改后将回到商品展示页面，此时数据已经修改。
by @sunhaiyu
2017.4.18
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