文章目录
1.项目初始化:点运行
面向接口编程就是接口类型的多态,只看左边。很多Servlet由Tomcat即web容器管理。只有cookie是类不是接口
。对象也叫实例。
web层和浏览器打交道,jsp写起来像前端,所以放入web文件夹下,但jsp就是servlet。dao层和数据库打交道,service层处理业务逻辑。如下web层中实现类对象
可用反射解耦,service层实现的东西可以放入配置文件中,用反射获取配置文件信息,动态构建一个实现类对象。如mybatis的实现都是写在配置文件里,底层就是反射和动态代理。
如下c3p0…xml放入src目录下,Data…java放入utils文件夹下,没有用druid。
如下前端直接粘到web文件夹路径下。
准备好上面5步后,点乌龟运行,自动跳转出浏览器并显示index.jsp。
点击上面蓝字是超链接跳转如下。
2.查询功能:xxServlet .java在web层,不在service层
如下index.jsp里的a标签不能跳转到list.jsp,因为list.jsp里是假数据,需要经过中间QueryListServlet查询出数据
传给list.jsp显示。不要请求参数,因为sql里不需要参数。sql是核心,查询出封装进bean对象,串联前后作用。因为要传数据,所以用请求转发。
2.1 前端
//index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<base href="<%=basePath%>"/>
<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>
<!--11111111111111111111111111111111111111111111111111111111111111111111111111111111-->
<body>
<div align="center"> <!--a标签点击默认是get请求,若要请求参数写成 ?n1=v1 -->
<a
href="/QueryListServlet" style="text-decoration:none;font-size:33px">查询所有用户信息
</a>
</div>
</body>
</html>
//list.jsp
<%@ 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 method01(id,name) {
var result = confirm("确认删除"+name+"吗?");
if(result){
location.href = "/DeteleServlet?id=" + id
}
}
</script>
</head>
<!--1111111111111111111111111111111111111111111111111111111111111111111111111111111-->
<body>
<div class="container">
<h3 style="text-align: center">用户信息列表</h3>
<table border="1" class="table table-bordered table-hover">
<tr class="success">
<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>
<%--TODO: status.count看遍历次数--%>
<c:forEach var="user" items="${list}" varStatus="status">
<tr>
<td>${user.id}</td>
<%-- <td>${status.count}</td>--%>
<td>${user.name}</td>
<td>${user.sex}</td>
<td>${user.age}</td>
<td>${user.address}</td>
<td>${user.qq}</td>
<td>${user.email}</td>
<td><a class="btn btn-default btn-sm" href="/QuerySingleServlet?id=${user.id}">修改</a>
<%--<a class="btn btn-default btn-sm" href="/DeteleServlet?id=${user.id}">删除</a>--%>
<%--
上行按钮注释了,没有删除按钮了
href = "javascript:void(0)" 或 javascript:;
a标签的默认点击事件会被禁止, a标签相当于按钮
--%>
<a class="btn btn-default btn-sm" href="javascript:void(0);" onclick="method01('${user.id}','${user.name}')">删除</a>
</td>
</tr>
</c:forEach>
<tr>
<td colspan="8" align="center"><a class="btn btn-primary" href="add.jsp">添加联系人</a></td>
</tr>
</table>
</div>
</body>
</html>
2.2 web
package com.itheima.manager.web; //放在..manager.web文件夹下
import com.itheima.manager.entity.User;
import com.itheima.manager.service.UserService;
import com.itheima.manager.service.impl.UserServiceImpl;
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.util.List;
@WebServlet(urlPatterns = "/QueryListServlet")
public class QueryListServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 接收请求,无请求参数
//2. 业务处理
UserService service = new UserServiceImpl(); //接口UserService 变量service = 实现类对象
List<User> list = service.queryAllUser(); //里面不需要传入参数,因为sql不需要
System.out.println(list);
//3. 响应数据(请求转发)
request.setAttribute("list",list);
request.getRequestDispatcher("/list.jsp").forward(request,response);
}
}
2.3 entity
package com.itheima.manager.entity;
//字段名 和 数据表字段
public class User {
private Integer id;
private String name;
private String sex;
private Integer age;
private String address;
private String qq;
private String email;
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", sex='" + sex + '\'' +
", age=" + age +
", address='" + address + '\'' +
", qq='" + qq + '\'' +
", email='" + email + '\'' +
'}';
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getQq() {
return qq;
}
public void setQq(String qq) {
this.qq = qq;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
2.4 service
package com.itheima.manager.service;
import com.itheima.manager.entity.User;
import java.util.List;
public interface UserService {
// 查询所有用户数据
List<User> queryAllUser();
//根据id删除用户
void deleteUser(String id);
//添加用户
void addUser(User user);
//查询单个用户
User querySingleUser(String id);
//修改用户信息
void updateUser(User user);
//分页查询
List<User> pageQuery(int offset, int count);
//查询用户总数
int findUserSum();
}
package com.itheima.manager.service.impl;
import com.itheima.manager.dao.UserDao;
import com.itheima.manager.dao.impl.UserDaoImpl;
import com.itheima.manager.entity.User;
import com.itheima.manager.service.UserService;
import java.util.List;
public class UserServiceImpl implements UserService {
UserDao dao = new UserDaoImpl();
@Override
public List<User> queryAllUser() {
List<User> list = dao.findAllUser();
return list;
}
@Override
public void deleteUser(String id) {
dao.deleteById(id);
}
@Override
public void addUser(User user) {
dao.addUser(user);
}
@Override
public User querySingleUser(String id) {
return dao.findSingleUser(id);
}
@Override
public void updateUser(User user) {
dao.updateUser(user);
}
@Override
public List<User> pageQuery(int offset, int count) {
List<User> list = dao.findUserByPage(offset,count);
return list;
}
@Override
public int findUserSum() {
int count = dao.findUserSum();
return count;
}
}
2.5 dao
package com.itheima.manager.dao;
import com.itheima.manager.entity.User;
import java.util.List;
public interface UserDao {
List<User> findAllUser();
void deleteById(String id);
void addUser(User user);
User findSingleUser(String id);
void updateUser(User user);
List<User> findUserByPage(int offset, int count);
int findUserSum();
}
package com.itheima.manager.dao.impl;
import com.itheima.manager.dao.UserDao;
import com.itheima.manager.entity.User;
import com.itheima.manager.utils.DataSourceUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import javax.sql.DataSource;
import java.util.List;
public class UserDaoImpl implements UserDao {
JdbcTemplate template = new JdbcTemplate(DataSourceUtils.getDataSource());
@Override
public List<User> findAllUser() {
String sql = "select * from t_user";
List<User> list = template.query(sql, new BeanPropertyRowMapper<>(User.class));
return list;
}
@Override
public void deleteById(String id) {
String sql = "delete from t_user where id = ?";
template.update(sql,id);
}
@Override
public void addUser(User user) {
String sql = "insert into t_user values(null,?,?,?,?,?,?)";
template.update(sql,
user.getName(),
user.getSex(),
user.getAge(),
user.getAddress(),
user.getQq(),
user.getEmail());
}
@Override
public User findSingleUser(String id) {
String sql = "select * from t_user where id = ?";
User user = null;
try {
user = template.queryForObject(sql, new BeanPropertyRowMapper<>(User.class), id);
} catch (DataAccessException e) {
e.printStackTrace(); //查不到数据会异常!!!!!!!!
}
return user;
}
@Override
public void updateUser(User user) {
String sql = "update t_user set name=?,sex=?,age=?,address=?,qq=?,email=? where id = ?";
template.update(sql,
user.getName(),
user.getSex(),
user.getAge(),
user.getAddress(),
user.getQq(),
user.getEmail(),
user.getId() );
}
@Override
public List<User> findUserByPage(int offset, int count) {
String sql = "select * from t_user limit ?,?";
List<User> list = template.query(sql, new BeanPropertyRowMapper<>(User.class), offset, count);
return list;
}
@Override
public int findUserSum() {
String sql = "select count(*) from t_user";
Integer count = template.queryForObject(sql,Integer.class);
return count;
}
}
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