jsp+servlet手机管理（增加和修改二）
在以上篇我们写了实现列表功能
一 ：新增功能
注意新增 不仅要增加手机 还要选择手机的品牌 ， 我们可以将手机品牌做成下拉列表框
首先 在t_list.jsp列表页面新增一个a标签 跳转新增界面
<a href="<%=request.getContextPath()%>/tel?method=tosave">新增</a>
虽然样式有点丑 ，勉强还能看 。 我们跳到新增界面后
先实现添加时品牌动态从数据库读取
Dao
在dao层创建TbrandDao 接口
List
<Tbrand> findAll();
接口实现类 TbrandDaoImpl
public List
<Tbrand> findAll() {
Connection connection
=null
;
PreparedStatement preparedStatement
=null
;
ResultSet resultSet
=null
;
String sql
="select * from t_brand";
List
<Tbrand> tbrandList
=null
;
Tbrand tbrand
=null
;
try {
tbrandList
=new ArrayList<>();
connection
= JDBCUtil
.getConnection();
preparedStatement
= connection
.prepareStatement(sql
);
resultSet
= preparedStatement
.executeQuery();
while (resultSet
.next()) {
tbrand
=new Tbrand();
tbrand
.setId(resultSet
.getInt("id"));
tbrand
.setDname(resultSet
.getString("dname"));
tbrandList
.add(tbrand
);
}
}catch (Exception e
){
e
.printStackTrace();
}finally {
JDBCUtil
.close(resultSet
,preparedStatement
,connection
);
}
return tbrandList
;
}
与我们上一期的列表有些许相似
service
然后实现我们的service层
TbrandService 接口
List
<Tbrand> findAll();
TbrandService 接口实现类 TbrandServiceImpl
public class TbrandServiceImpl implements TbrandService {
private TbrandDao tbrandDao
=new TbrandDaoImpl();
@Override
public List
<Tbrand> findAll() {
return tbrandDao
.findAll();
}
}
Telservlet
在doPost方法中 还是老样子 判断请求地址
String method
= request
.getParameter("method");
if ("findAll".equals(method
)){
findAll(request
,response
);
}else if ("tosave".equals(method
)){
tosave(request
,response
);
}
}
private void tosave(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
List
<Tbrand> tbrandList
= tbrandService
.findAll();
request
.setAttribute("tbrandList",tbrandList
);
request
.getRequestDispatcher("/t_save.jsp").forward(request
,response
);
}
protected void doGet(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
doPost(request
,response
);
}
创建 新增页面 t_save.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>新增</title>
</head>
<body>
<form action="<%=request.getContextPath()%>/tel?method=saveTel" method="post">
名称:<input type="text" name="name"><br>
品牌:<select name="bid">
<c:forEach items="${requestScope.tbrandList}" var="tbrandList">
<option value="${tbrandList.id}">${tbrandList.dname}</option>
</c:forEach>
</select>
<input type="submit" value="提交">
</form>
</body>
</html>
接下来我们实现新增功能
在TelDao里 添加新方法
void save(Tel tel
);
在TelDaoImpl接口实现类实现该方法
@Override
public void save(Tel tel
) {
Connection connection
=null
;
PreparedStatement preparedStatement
=null
;
String sql
="insert into t_tel set name=?,bid=?";
try {
connection
= JDBCUtil
.getConnection();
preparedStatement
= connection
.prepareStatement(sql
);
preparedStatement
.setString(1,tel
.getName());
preparedStatement
.setInt(2,tel
.getBid());
preparedStatement
.executeUpdate();
}catch (Exception e
){
e
.printStackTrace();
}finally {
JDBCUtil
.close(null
,preparedStatement
,connection
);
}
}
下面就是TelService接口 添加新方法：
void save(Tel tel
);
TelServiceImpl 实现 新方法
public void save(Tel tel
) {
telDao
.save(tel
);
}
Telservlet
还是老样子 判断请求参数
protected void doPost(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
String method
= request
.getParameter("method");
if ("findAll".equals(method
)){
findAll(request
,response
);
}else if ("tosave".equals(method
)){
tosave(request
,response
);
}else if ("saveTel".equals(method
)){
saveTel(request
,response
);
}
}
private void saveTel(HttpServletRequest request
, HttpServletResponse response
) throws IOException
{
String name
= request
.getParameter("name");
String bid
= request
.getParameter("bid");
Tel tel
= new Tel();
tel
.setBid(Integer
.parseInt(bid
));
tel
.setName(name
);
telService
.save(tel
);
response
.sendRedirect(request
.getContextPath()+"/tel?method=findAll");
}
protected void doGet(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
doPost(request
,response
);
}
二： 更新功能
1. 我们先点击更新按钮实现一个数据的回显
<td>
<button οnclick="update(${vo.id})">更新</button>
</td>
<script>
function update(id) {
location.href="<%=request.getContextPath()%>/tel?method=toUpdate&id="+id
}
</script>
根据Id来查站我们的数据
TelDao创建新方法
Tel
findById(Integer id
);
TelDaoImpl实现接口方法
public Tel
findById(Integer id
) {
Connection connection
=null
;
PreparedStatement preparedStatement
=null
;
ResultSet resultSet
=null
;
String sql
="select id,name,bid from t_tel where id=?";
Tel tel
=null
;
try {
connection
= JDBCUtil
.getConnection();
preparedStatement
= connection
.prepareStatement(sql
);
preparedStatement
.setInt(1,id
);
resultSet
= preparedStatement
.executeQuery();
if (resultSet
.next()) {
tel
=new Tel();
tel
.setId(resultSet
.getInt("id"));
tel
.setName(resultSet
.getString("name"));
tel
.setBid(resultSet
.getInt("bid"));
}
}catch (Exception e
){
e
.printStackTrace();
}finally {
JDBCUtil
.close(resultSet
,preparedStatement
,connection
);
}
return tel
;
}
Telservice 添加新方法
Tel
findById(Integer id
);
TelServiceImpl 实现该方法
public Tel
findById(Integer id
) {
return telDao
.findById(id
);
}
Telservlet
protected void doPost(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
String method
= request
.getParameter("method");
if ("findAll".equals(method
)){
findAll(request
,response
);
}else if ("tosave".equals(method
)){
tosave(request
,response
);
}else if ("saveTel".equals(method
)){
saveTel(request
,response
);
}else if ("toUpdate".equals(method
)){
toUpdate(request
,response
);
}
}
private void toUpdate(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
String id
= request
.getParameter("id");
Tel byId
= telService
.findById(Integer
.parseInt(id
));
List
<Tbrand> tbrands
= tbrandService
.findAll();
request
.setAttribute("byId",byId
);
request
.setAttribute("tbrands",tbrands
);
request
.getRequestDispatcher("/t_update.jsp").forward(request
,response
);
}
protected void doGet(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
doPost(request
,response
);
}
t_update.jsp 页面
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>更新</title>
</head>
<body>
<form action="<%=request.getContextPath()%>/tel?method=updateTel" method="post">
<input type="hidden" name="id" value="${requestScope.byId.id}">
<br>
名称：<input type="text" name="name" value="${requestScope.byId.name}"><br>
品牌：<select name="bid">
<c:forEach items="${requestScope.tbrands}" var="tbs">
<option value="${tbs.id}"
<!--根据id来判断-->
<c:if test="${tbs.id==requestScope.byId.bid}">
selected
</c:if>
>${tbs.dname}
</option>
</c:forEach>
</select>
<input type="submit" value="提交">
</form>
</body>
</html>
2. 更新功能
TelDao
void updateTel(Tel tel
);
TelDaoImpl
public void updateTel(Tel tel
) {
Connection connection
=null
;
PreparedStatement preparedStatement
=null
;
String sql
="update t_tel set name=?, bid=? where id=?";
try {
connection
= JDBCUtil
.getConnection();
preparedStatement
= connection
.prepareStatement(sql
);
preparedStatement
.setString(1,tel
.getName());
preparedStatement
.setInt(2,tel
.getBid());
preparedStatement
.setInt(3,tel
.getId());
preparedStatement
.executeUpdate();
}catch (Exception e
){
e
.printStackTrace();
}finally {
JDBCUtil
.close(null
,preparedStatement
,connection
);
}
}
TelService
void updateTel(Tel tel
);
TelServiceImpl
public void updateTel(Tel tel
) {
telDao
.updateTel(tel
);
}
Telservlet
protected void doPost(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
String method
= request
.getParameter("method");
if ("toUpdate".equals(method
)){
toUpdate(request
,response
);
}else if ("updateTel".equals(method
)){
updateTel(request
,response
);
}
}
private void updateTel(HttpServletRequest request
, HttpServletResponse response
) throws IOException
{
String id
= request
.getParameter("id");
String name
= request
.getParameter("name");
String bid
= request
.getParameter("bid");
Tel tel
= new Tel();
tel
.setId(Integer
.parseInt(id
));
tel
.setName(name
);
tel
.setBid(Integer
.parseInt(bid
));
telService
.updateTel(tel
);
response
.sendRedirect(request
.getContextPath()+"/tel?method=findAll");
}
protected void doGet(HttpServletRequest request
, HttpServletResponse response
) throws ServletException
, IOException
{
doPost(request
,response
);
}
