资料来源黑马JAVA2019
登入和验证码板块,已经在上几篇文章中写到了,这里只需要按照三层架构模式,改写一些代码即可。开发文件结构如图所示:
按照DAO,SERVICE负责页面展示的Servlet等分门别类摆放。
主要看注释和图!
具体代码由于跳转和调用太多,要看整体代码https://github.com/miraclekowk/HeiMaJavaPractice_Day17
查询所有用户信息
代码逻辑:
DAO层–实现:
public class UserDaoImpl implements UserDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
//查询模块
@Override
public List<User> findAll() {
//使用JDBC操作数据库 查询
String sql = "select * from user";
List<User> users = template.query(sql, new BeanPropertyRowMapper<User>(User.class));
return users;
}
//登入模块
@Override
public User findUserByUsernameAndPassword(String username, String password) {
try {
String sql = "select * from user where username = ? and password = ?";
User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
return user;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
UserService层实现:
public class UserServiceImpl implements UserService {
private UserDao dao = new UserDaoImpl();
@Override
public List<User> findAll() {
//调用dao完成查询
return dao.findAll();
}
@Override
public User login(User user) {
String userName = user.getUsername();
String passWord = user.getPassword();
System.out.println(userName + " " + passWord);
User userByUsernameAndPassword = dao.findUserByUsernameAndPassword(userName, passWord);
return userByUsernameAndPassword;
}
}
UserList层实现:
@WebServlet("/userListServlet")
public class UserListServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.调用UserService完成查询
UserService service = new UserServiceImpl();
List<User> users = service.findAll();
System.out.println("现有的信息条数" + users.size());
//2.将list放入域
request.setAttribute("users",users);
//转发到list.jsp
request.getRequestDispatcher("/list.jsp").forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
LoginServlet:
这里有两个做练习的过程中的错误点:
1.由于前端的list.jsp中的标签的name的规定,所以定义domin中User类的私有变量,必须和标签同名(大小写敏感)。不然咋找输入参数嘛?
2.如果发现登入问题,则优先去查看sql查询代码有没有写对,可以在sqlyog中手动输入来查询
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.设置编码
request.setCharacterEncoding("utf-8");
//2.获取验证码数据
String verifycode = request.getParameter("verifycode");
//3.验证码效验
HttpSession session = request.getSession();
String checkCode_server = (String) session.getAttribute("CHECKCODE_SERVER");
//确保验证码的一次性
session.removeAttribute("CHECKCODE_SERVER");
if(!checkCode_server.equalsIgnoreCase(verifycode))
{
//验证码不正确 给提示信息跳转登入页面
request.setAttribute("verify_fail","验证码错误!");
request.getRequestDispatcher("/login.jsp").forward(request,response);
return;
}
Map<String, String[]> parameterMap = request.getParameterMap();
//4.封装user对象
User user = new User();
try {
//BeanUtils.populate( Object bean, Map properties )
//这个方法会遍历map<key, value>中的key,如果bean中有这个属性,就把这个key对应的value值赋给bean的属性。
//!!!注意这里面的username(jsp中的标签name)一定要和User类中的成员变量一样 大小写敏感
BeanUtils.populate(user,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
System.out.println("现在我在封装对象" + user.getUsername()+" " + user.getPassword());
//5.调用Service查询
UserService Service = new UserServiceImpl();
User loginUser = Service.login(user);
//6.判断是否登入成功
if(loginUser != null)
{
//登入成功 信息进入session域
session.setAttribute("user",loginUser);
response.sendRedirect(request.getContextPath()+"/index.jsp");
}
else
{
request.setAttribute("login_fail","用户名或密码错误");
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
前端 index.jsp (主要用来跳转到 userListServlet处理再转发到list.jsp)
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>首页</title>
<!-- 1. 导入CSS的全局样式 -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- 2. jQuery导入,建议使用1.9以上的版本 -->
<script src="js/jquery-2.1.0.min.js"></script>
<!-- 3. 导入bootstrap的js文件 -->
<script src="js/bootstrap.min.js"></script>
<script type="text/javascript">
</script>
</head>
<body>
<div align="center">
<a
href="${pageContext.request.contextPath}/userListServlet" style="text-decoration:none;font-size:33px">查询所有用户信息
</a>
</div>
</body>
</html>
前端 list.jsp
注意这里的EL写法的迭代写法:
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<c:forEach items="${users}" var="user" varStatus="s">
<tr>
<td><input type="checkbox" name="uid" value="${user.id}"></td>
<td>${s.count}</td>
<td>${user.name}</td>
<td>${user.gender}</td>
<td>${user.age}</td>
<td>${user.address}</td>
<td>${user.qq}</td>
<td>${user.email}</td>
<td><a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a>
<a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a></td>
</tr>
</c:forEach>
需要注意以下几点:
1、items相当于list,就是你要循环的那个容器。
2、var相当于list中装有的每个独立物体的临时变量。
3、varStatus是循环状态对象,常用s.index和s.count。
S.index:代表容器中元素的索引,从0开始。相当于for(int i = 0;i < n;i++)中的i
S.count:代表循环次数,从1开始。
这种写法等价于for(User user : list) 遍历容器写法。
此外还有完成重复操作写法,等价于for(int i = 0;i < n;i++)。foreach写法有以下属性:
begin:开始值
end:结束值
step:步长
var:临时变量
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html lang="zh-CN">
<head>
<!-- 指定字符集 -->
<meta charset="utf-8">
<!-- 使用Edge最新的浏览器的渲染方式 -->
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<!-- viewport视口:网页可以根据设置的宽度自动进行适配,在浏览器的内部虚拟一个容器,容器的宽度与设备的宽度相同。
width: 默认宽度与设备的宽度相同
initial-scale: 初始的缩放比,为1:1 -->
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
<title>用户信息管理系统</title>
<!-- 1. 导入CSS的全局样式 -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- 2. jQuery导入,建议使用1.9以上的版本 -->
<script src="js/jquery-2.1.0.min.js"></script>
<!-- 3. 导入bootstrap的js文件 -->
<script src="js/bootstrap.min.js"></script>
<style type="text/css">
td, th {
text-align: center;
}
</style>
<script>
function deleteUser(id){
//用户安全提示
if(confirm("您确定要删除吗?")){
//访问路径
location.href="${pageContext.request.contextPath}/delUserServlet?id="+id;
}
}
window.onload = function(){
//给删除选中按钮添加单击事件
document.getElementById("delSelected").onclick = function(){
if(confirm("您确定要删除选中条目吗?")){
var flag = false;
//判断是否有选中条目
var cbs = document.getElementsByName("uid");
for (var i = 0; i < cbs.length; i++) {
if(cbs[i].checked){
//有一个条目选中了
flag = true;
break;
}
}
if(flag){
//有条目被选中
//表单提交
document.getElementById("form").submit();
}
}
}
//1.获取第一个cb
document.getElementById("firstCb").onclick = function(){
//2.获取下边列表中所有的cb
var cbs = document.getElementsByName("uid");
//3.遍历
for (var i = 0; i < cbs.length; i++) {
//4.设置这些cbs[i]的checked状态 = firstCb.checked
cbs[i].checked = this.checked;
}
}
}
</script>
</head>
<body>
<div class="container">
<h3 style="text-align: center">用户信息列表</h3>
<div style="float: left;">
<form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
<div class="form-group">
<label for="exampleInputName2">姓名</label>
<input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2" >
</div>
<div class="form-group">
<label for="exampleInputName3">籍贯</label>
<input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputName3" >
</div>
<div class="form-group">
<label for="exampleInputEmail2">邮箱</label>
<input type="text" name="email" value="${condition.email[0]}" class="form-control" id="exampleInputEmail2" >
</div>
<button type="submit" class="btn btn-default">查询</button>
</form>
</div>
<div style="float: right;margin: 5px;">
<a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>
<a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a>
</div>
<form id="form" action="${pageContext.request.contextPath}/delSelectedServlet" method="post">
<table border="1" class="table table-bordered table-hover">
<tr class="success">
<th><input type="checkbox" id="firstCb"></th>
<th>编号</th>
<th>姓名</th>
<th>性别</th>
<th>年龄</th>
<th>籍贯</th>
<th>QQ</th>
<th>邮箱</th>
<th>操作</th>
</tr>
<c:forEach items="${users}" var="user" varStatus="s">
<tr>
<td><input type="checkbox" name="uid" value="${user.id}"></td>
<td>${s.count}</td>
<td>${user.name}</td>
<td>${user.gender}</td>
<td>${user.age}</td>
<td>${user.address}</td>
<td>${user.qq}</td>
<td>${user.email}</td>
<td><a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a>
<a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a></td>
</tr>
</c:forEach>
</table>
</form>
<div>
<nav aria-label="Page navigation">
<ul class="pagination">
<c:if test="${pb.currentPage == 1}">
<li class="disabled">
</c:if>
<c:if test="${pb.currentPage != 1}">
<li>
</c:if>
<a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage - 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
<span aria-hidden="true">«</span>
</a>
</li>
<c:forEach begin="1" end="${pb.totalPage}" var="i" >
<c:if test="${pb.currentPage == i}">
<li class="active"><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
</c:if>
<c:if test="${pb.currentPage != i}">
<li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
</c:if>
</c:forEach>
<li>
<a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage + 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next">
<span aria-hidden="true">»</span>
</a>
</li>
<span style="font-size: 25px;margin-left: 5px;">
共${pb.totalCount}条记录,共${pb.totalPage}页
</span>
</ul>
</nav>
</div>
</div>
</body>
</html>
分页查询用户信息
比较复杂,需要前端传过来两个参数,一是当前页面currentPage,二是一页展示多少行rows。
实现分页所需的参数:
分页查询具体逻辑:
Servlet层:
@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.获取参数
String currentPage = request.getParameter("currentPage"); //当前页码
String rows = request.getParameter("rows"); //每页显示的条数
//获取条件查询参数
Map<String, String[]> condition = request.getParameterMap();
//2.调用service查询 为了满足条件查询,需要把condition参数传进去
UserServiceImpl service = new UserServiceImpl();
PageBean<User> pb = service.findUserByPage(currentPage,rows,condition);
//3.存储数据
request.setAttribute("pb",pb);
request.setAttribute("condition",condition);
//4.转发
request.getRequestDispatcher("/list.jsp").forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
Service层方法:
@Override
public PageBean<User> findUserByPage(String _currentPage, String _rows, Map<String, String[]> condition) {
int currentPage = Integer.parseInt(_currentPage);
int rows = Integer.parseInt(_rows);
//防止用户一直点上一页点到负数
if(currentPage <= 0)
currentPage = 1;
//1.创建空pagebean
PageBean<User> pb = new PageBean<>();
//2.设置参数
pb.setCurrentPage(currentPage);
pb.setRows(rows);
//3.调用dao查询总记录数
int totalCount = dao.findTotalCount(condition);
pb.setTotalCount(totalCount);
//4.调用dao查询List集合
//计算开始的记录索引 封装查询结果(list)
int start = (currentPage - 1) * rows;
List<User> list = dao.findByPage(start,rows,condition);
pb.setList(list);
//5.计算总页码 比如63条记录,每页10行则一共有7页
int totalPage = totalCount % rows == 0 ? totalCount/rows : totalCount/rows + 1;
pb.setTotalPage(totalPage);
return pb;
}
DAO层方法:findTotalCount算出符合条件(为了配合条件查询)的有多少条数据,findByPage来找具体数据。
@Override
public int findTotalCount(Map<String, String[]> condition) {
//1.定义模板初始化sql
String sql = "select count(*) from user where 1 = 1 ";
StringBuilder sb = new StringBuilder(sql);
//2.遍历map
Set<String> keySet = condition.keySet();
//定义参数的集合
List<Object> params = new ArrayList<Object>();
for (String key : keySet) {
//排除分页条件参数
if("currentPage".equals(key) || "rows".equals(key)){
continue;
}
//获取value
String value = condition.get(key)[0];
//判断value是否有值
if(value != null && !"".equals(value)){
//有值
sb.append(" and "+key+" like ? ");
params.add("%"+value+"%");//?条件的值
}
}
System.out.println(sb.toString());
System.out.println(params);
return template.queryForObject(sb.toString(),Integer.class,params.toArray());
}
@Override
public List<User> findByPage(int start, int rows, Map<String, String[]> condition) {
String sql = "select * from user where 1 = 1 ";
StringBuilder sb = new StringBuilder(sql);
//2.遍历map
Set<String> keySet = condition.keySet();
//定义参数的集合
List<Object> params = new ArrayList<Object>();
for (String key : keySet) {
//排除分页条件参数
if("currentPage".equals(key) || "rows".equals(key)){
continue;
}
//获取value
String value = condition.get(key)[0];
//判断value是否有值
if(value != null && !"".equals(value)){
//有值
sb.append(" and "+key+" like ? ");
params.add("%"+value+"%");//?条件的值
}
}
//添加分页查询
sb.append(" limit ?,? ");
//添加分页查询参数值
params.add(start);
params.add(rows);
sql = sb.toString();
System.out.println(sql);
System.out.println(params);
return template.query(sql,new BeanPropertyRowMapper<User>(User.class),params.toArray());
}
此外,当然要有PageBean来封装分页数据:
package cn.domain;
import java.util.List;
//加泛型是为了通用性,现在用user,以后可以装别的比如manager
public class PageBean<T> {
private int totalCount;//总记录数
private int totalPage;//总页码
private List<T> list;//每页的数据
private int currentPage; //当前页码
private int rows; //每页显示的记录数
public int getTotalCount() {
return totalCount;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public List<T> getList() {
return list;
}
public void setList(List<T> list) {
this.list = list;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getRows() {
return rows;
}
public void setRows(int rows) {
this.rows = rows;
}
@Override
public String toString() {
return "PageBean{" +
"totalCount=" + totalCount +
", totalPage=" + totalPage +
", list=" + list +
", currentPage=" + currentPage +
", rows=" + rows +
'}';
}
}
增:添加用户
添加数据条目的实现逻辑:
Servlet层:
遇到Bug:存数据库这一下发生乱码问题 在这行之前(封装过程)打印出来都是ok的
解决:在druid里面加characterencoding参数 = utf-8
e.g.
url=jdbc:mysql:///day17?characterEncoding=utf-8
@WebServlet("/addUserServlet")
public class AddUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
//获取参数
Map<String, String[]> parameterMap = request.getParameterMap();
//封装对象
User user = new User();
try {
BeanUtils.populate(user,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//System.out.println(user.getName()+" "+user.getAddress());
//调用Service保存
//!!! 存进去这一下发生乱码问题 在这行之前(封装过程)打印出来都是ok的 解决:在druid里面加characterencoding参数 = utf-8
UserServiceImpl Service = new UserServiceImpl();
Service.addUser(user);
//跳转到userListServlet (因为加入完后还要查询一次)
response.sendRedirect(request.getContextPath() + "/userListServlet");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
Service层:
@Override
public void addUser(User user) {
dao.add(user);
}
Dao层:
@Override
public void add(User user) {
//1.定义sql
String sql = "insert into user values(null,?,?,?,?,?,?,null,null)";
//2.执行sql
template.update(sql,user.getName(),user.getGender(),user.getAge(),
user.getAddress(),user.getQq(),user.getEmail());
System.out.println(user.getName());
}
改:修改按钮-》1.回显信息在页面上 2.再次提交
逻辑:
1.选中某条信息打钩,需要传到后端某个唯一标识:“id”
2.回显这条的相关信息在一个修改.jsp中。
3.用户改动后,再次提交,并调转到查询所有用户上。
找到用户在修改哪条信息并返回User供前端回显
//用来修改的用户信息的,先找到,再修改
@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.获取查找所需的id参数
String id = request.getParameter("id");
//2.调用service查询
UserServiceImpl Service = new UserServiceImpl();
User user = Service.findUserById(id);
//3.把user转发
request.setAttribute("user",user);
request.getRequestDispatcher("/update.jsp").forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
找到用户修改哪条的Service层:
public User findUserById(String id) {
return dao.findById(Integer.parseInt(id));
}
DAO层:
@Override
public User findById(int id) {
String sql = "select * from user where id = ?";
return template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class),id);
}
更新数据库:
Servlet层:
@WebServlet("/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.设置编码
request.setCharacterEncoding("utf-8");
//2.获取map 这里面id被偷偷传进来了,用户是看不见的,id在隐藏框中
Map<String, String[]> parameterMap = request.getParameterMap();
//3.封装对象
User user = new User();
try {
BeanUtils.populate(user,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//4.调用Service修改
UserServiceImpl Service = new UserServiceImpl();
Service.updateUser(user);
//5.转发 重新查询整个列表 没有传参可以用重定向完成
response.sendRedirect(request.getContextPath() + "/userListServlet");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
Service层:
@Override
public void updateUser(User user) {
dao.update(user);
}
DAO层:
@Override
public void update(User user) {
String sql = "update user set name = ?,gender = ?,age = ?,address = ?,qq = ?,email = ? where id = ?";
template.update(sql, user.getName(), user.getGender(), user.getAge(),
user.getAddress(), user.getQq(), user.getEmail(), user.getId());
}
删:删除选中条目
1.同样利用唯一标识符Id来选中用户要删除的条目,在前端中组成数组传入后端
2.dao层直接调用删除即可,用户确认删除的逻辑在前端JSP中已经实现了。
3.同样的,删除完要跳转回查询页面。
基础逻辑:单次删除
进阶逻辑,选中删除:
Servlet层:
@WebServlet("/delSelectedServlet")
public class DelSelectedServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.获取所有的id
String[] ids = request.getParameterValues("uid");
//2.调用service删除
UserServiceImpl service = new UserServiceImpl();
service.delSelectedUser(ids);
//3.跳转查询所有的service
response.sendRedirect(request.getContextPath()+"/userListServlet");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
Service层:
public void delSelectedUser(String[] ids) {
//1.遍历数组
for (String id : ids) {
//调用dao删除
dao.delet(Integer.parseInt(id));
}
}
DAO层:
@Override
public void delet(int id) {
//1.定义sql
String sql = "delete from user where id = ?";
//执行sql
template.update(sql,id);
}