cookie和session的关系
两者都是在客户端和服务器中进行存储数据和传递信息的工具
cookie和session的区别
Cookie是客⼾端保存⽤⼾信息的⼀种机制.
Session是服务器端保存⽤⼾信息的⼀种机制.
Cookie和Session之间主要是通过SessionId关联起来的，SessionId是Cookie和Session之间的 桥梁。
Cookie和Session经常会在⼀起配合使⽤.但是不是必须配合，完全可以⽤Cookie来保存⼀些数据在客⼾端.这些数据不⼀定是⽤⼾⾝份信息,也不⼀定是 SessionId。
获取cookie
传统的获取cookie
HttpServletRequest , HttpServletResponse 是Servlet提供的两个类,是Spring MVC⽅法的内置对象.需要时直接在⽅法中添加声明即可
HttpServletRequest:对象代表客户端的请求当客户端通过Http协议访问服务端时，Http请求中的所有信息封装在这个对象中，通过这个对象提供的方法，可以获得客户端的所有信息
HttpServletResponse 对象代表服务器的响应.HTTP响应的信息都在这个对象中
//传统的获取cookie
@RequestMapping("t13")
public String t13(HttpServletRequest request, HttpServletResponse response){
Cookie[] cookies = request.getCookies();
if(cookies!=null){
for (Cookie cookie:cookies) {
System.out.println(cookie.getName()+":"+cookie.getValue());
}
}
return "返回cookie成功";
}
利用注释获取cookie的方式
//利用注解获取cookie
@RequestMapping("t14")
public String t14(@CookieValue("java") String java){
return "获取cookie中的java成功"+ java;
}session的存储与获取
session的存储
//存储session
@RequestMapping("/setSession")
public String setSession(HttpServletRequest request){
HttpSession session = request.getSession();
session.setAttribute("username","zhangsan");
session.setAttribute("age","17");
return "设置session成功";
}
session的获取
方法一：
//获取session,方法一
@RequestMapping("/getSession1")
public String getSession1(HttpServletRequest request){
HttpSession session = request.getSession(/*true*/);
if (session==null){
return "获取失败";
}else {
String username =(String) session.getAttribute("username");
// Integer age =(Integer) session.getAttribute("age");
return "登录的用户为"+ username;
}
}
方法二：
//获取session,方法二
@RequestMapping("/getSession2")
public String getSession2(HttpSession session){
//HttpSession session默认session中的值为true,所以可以省略session为0
String username =(String) session.getAttribute("username");
return "登录的用户为"+ username;
}
方法三：
//获取session,方法三
@RequestMapping("/getSession3")
public String getSession3(@SessionAttribute("username") String username){
return "登录的用户为"+ username;
}
获取header
传统的获取header
@RequestMapping("/getHeader1")
public String getHeader1(HttpServletRequest request){
String UserAgent = request.getHeader("User-Agent");
return "从header中获取User-Agent"+UserAgent;
}
通过抓包，发现获取的user-agent正确
简洁的获取header
@RequestMapping("/getHeader2")
public String getHeader2(@RequestHeader("User-Agent")String UserAgent){
return "从header中获取User-Agent"+UserAgent;
}
响应
返回静态的页面
在创建前端的页面时，注意路径
在resources包中
比如index.html前端代码
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>用户登录首页</title>
</head>
<body>
登录人: <span id="loginUser"></span>
<script src="js/jquery-git.min.js"></script>
<script>
$.ajax({
url: "/user/getLoginUser",
type: "get",
success: function(userName){
$("#loginUser").text(userName);
}
});
</script>
</body>
</html>后端的代码
public class ResponseController {
@RequestMapping("/t1")
public String returnPage(){
return "/index.html";
}
返回数据
@requestBody
@RequestMapping("/t2")
@ResponseBody
public String returnData(){
return "返回需要的数据";
}
返回html的代码片段
@ResponseBody
@RequestMapping("/t3")
public String returnHTML(){
return "<h1>我是一级标题</h1>";
} 
返回JSON
@ResponseBody
@RequestMapping(value = "/t5")
public UseInfo returnJson(){
UseInfo useInfo=new UseInfo("zhangsan",1,1);
return useInfo;
}
设置状态码
@ResponseBody
@RequestMapping(value = "/t6")
public UseInfo steStatus(HttpServletResponse response){
response.setStatus(404);
UseInfo useInfo=new UseInfo("zhangsan",1,1);
return useInfo;
}
用户的登录
前端代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登录页面</title>
</head>
<body>
<h1>用户登录</h1>
用户名：<input name="userName" type="text" id="userName"><br>
密码：<input name="password" type="password" id="password"><br>
<input type="button" value="登录" onclick="login()">
<script src="js/jquery-git.min.js"></script>
<script>
function login() {
$.ajax({
type: "POST",
url: "/user/login",
data: {
userName: $("#userName").val(),
password: $("#password").val()
},
success: function(result) {
if (result) {
location.href = "index.html";
} else {
alert("密码错误，请确认");
}
},
error: function(xhr, status, error) {
alert("请求失败，请稍后再试：" + error);
}
});
}
</script>
</body>
</html>后端代码
package com.blame.spring.demo;
import ch.qos.logback.core.util.StringUtil;
import jakarta.servlet.http.HttpSession;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RequestMapping("/user")
@RestController
public class UserController {
@RequestMapping("/login")
public boolean login(String userName, String passWord, HttpSession session){
if(!StringUtils.hasLength(userName) || !StringUtils.hasLength(passWord)){
return false;
}
if("admin".equals(userName) && "admin".equals(passWord)){
session.setAttribute(userName,"userName");
return true;
}
return false;
}
@RequestMapping("/getUserLogin")
public String getUserLogin(String userName,HttpSession session){
String attribute =(String) session.getAttribute("userName");
return userName;
}
}接口的定义
登录界面的接口定义
$.ajax({
type: "POST",
url: "/user/login",
data: {
userName: $("#userName").val(),
password: $("#password").val()
},
success: function(result) {
if (result) {
location.href = "index.html";
} else {
alert("密码错误，请确认");
}
},
error: function(xhr, status, error) {
alert("请求失败，请稍后再试：" + error);
}
});
计算器的实现
前端的代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<form action="calc/sum" method="post">
<h1>计算器</h1>
数字1：<input name="num1" type="text"><br>
数字2：<input name="num2" type="text"><br>
<input type="submit" value=" 点击相加 ">
</form>
</body>
</html>后端代码
@RequestMapping("/calc")
@RestController
public class CalcController {
@RequestMapping("/sum")
public String sum(Integer num1,Integer num2){
if(num1==null || num2==null){
return "输入错误，请重新输入";
}
Integer sum=num1+num2;
return "结果是"+ sum;
}
}留言板的实现
前端代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>留言板</title>
<style>
.container {
width: 350px;
height: 300px;
margin: 0 auto;
/* border: 1px black solid; */
text-align: center;
}
.grey {
color: grey;
}
.container .row {
width: 350px;
height: 40px;
display: flex;
justify-content: space-between;
align-items: center;
}
.container .row input {
width: 260px;
height: 30px;
}
#submit {
width: 350px;
height: 40px;
background-color: orange;
color: white;
border: none;
margin: 10px;
border-radius: 5px;
font-size: 20px;
}
</style>
</head>
<body>
<div class="container">
<h1>留言板</h1>
<p class="grey">输入后点击提交, 会将信息显示下方空白处</p>
<div class="row">
<span>谁:</span> <input type="text" name="" id="from">
</div>
<div class="row">
<span>对谁:</span> <input type="text" name="" id="to">
</div>
<div class="row">
<span>说什么:</span> <input type="text" name="" id="say">
</div>
<input type="button" value="提交" id="submit" onclick="submit()">
<!-- <div>A 对 B 说: hello</div> -->
</div>
<script src="js/jquery-git.min.js"></script>
<script>
load();
function load() {
$.ajax({
type: "get",
url: "/message/getList",
success: function (messages) {
if (messages != null && messages.length > 0) {
var finalHtml = "";
for (var m of messages) {
finalHtml += "<div>" + m.from + "对" + m.to + "说:" + m.message + "</div>";
}
$(".container").append(finalHtml);
}
}
});
}
function submit(){
//1. 获取留言的内容
var from = $('#from').val();
var to = $('#to').val();
var say = $('#say').val();
if (from== '' || to == '' || say == '') {
return;
}
$.ajax({
type:"post",
url:"/message/publish",
contentType:"application/json",
data:JSON.stringify({
from:from,
to:to,
message:say
}),
success:function(result){
var jsonObj = JSON.parse(result);
if(jsonObj.ok==1){
//2. 构造节点
var divE = "<div>"+from +"对" + to + "说:" + say+"</div>";
//3. 把节点添加到页面上
$(".container").append(divE);
//4. 清空输入框的值
$('#from').val("");
$('#to').val("");
$('#say').val("");
}else{
alert("发布失败")
}
}
});
}
</script>
</body>
</html>后端代码
package com.blame.spring.demo;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
@RequestMapping("/message")
@RestController
public class MessageController {
List<MessageInfo> messageInfoList=new ArrayList<>();
@PostMapping(value = "/publish",produces = "application/json")
public String publish(@RequestBody MessageInfo messageInfo){
if(!StringUtils.hasLength(messageInfo.getMessage())
|| !StringUtils.hasLength(messageInfo.getFrom())
|| !StringUtils.hasLength(messageInfo.getTo())){
return "{\"ok\":0}";
}
messageInfoList.add(messageInfo);
return "{\"ok\":1}";
}
@GetMapping("getList")
public List<MessageInfo> getList(){
return messageInfoList;
}
}接口的定义
lombok工具的介绍
Lombok是⼀个Java⼯具库，通过添加注解的⽅式，简化Java的开发
首先先引入其依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>@Data
public class MessageInfo {
private String from;
private String to;
private String message;
}@Data 注解会帮助我们⾃动⼀些⽅法,包含getter/setter,equals,toString等
如下图：上面是Java程序的运行原理，下面是Lombok的作用
我们就不需要自己写getter和setter方法还有toString方法
@Data=@Getter+@Setter+@ToString+@EqualsAndHashCode+@RequiredArgsConstructor + @NoArgsConstructor
图书管理系统的实现
首先先做好前端代码的引入
前端代码仅供参考，重点看后端的代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>添加图书</title>
<link rel="stylesheet" href="css/bootstrap.min.css">
<link rel="stylesheet" href="css/add.css">
</head>
<body>
<div class="container">
<div class="form-inline">
<h2 style="text-align: left; margin-left: 10px;"><svg xmlns="http://www.w3.org/2000/svg" width="40"
fill="#17a2b8" class="bi bi-book-half" viewBox="0 0 16 16">
<path
d="M8.5 2.687c.654-.689 1.782-.886 3.112-.752 1.234.124 2.503.523 3.388.893v9.923c-.918-.35-2.107-.692-3.287-.81-1.094-.111-2.278-.039-3.213.492V2.687zM8 1.783C7.015.936 5.587.81 4.287.94c-1.514.153-3.042.672-3.994 1.105A.5.5 0 0 0 0 2.5v11a.5.5 0 0 0 .707.455c.882-.4 2.303-.881 3.68-1.02 1.409-.142 2.59.087 3.223.877a.5.5 0 0 0 .78 0c.633-.79 1.814-1.019 3.222-.877 1.378.139 2.8.62 3.681 1.02A.5.5 0 0 0 16 13.5v-11a.5.5 0 0 0-.293-.455c-.952-.433-2.48-.952-3.994-1.105C10.413.809 8.985.936 8 1.783z" />
</svg>
<span>添加图书</span>
</h2>
</div>
<form id="addBook">
<div class="form-group">
<label for="bookName">图书名称:</label>
<input type="text" class="form-control" placeholder="请输入图书名称" id="bookName" name="bookName">
</div>
<div class="form-group">
<label for="bookAuthor">图书作者</label>
<input type="text" class="form-control" placeholder="请输入图书作者" id="bookAuthor" name="author" />
</div>
<div class="form-group">
<label for="bookStock">图书库存</label>
<input type="text" class="form-control" placeholder="请输入图书库存" id="bookStock" name="count"/>
</div>
<div class="form-group">
<label for="bookPrice">图书定价：</label>
<input type="number" class="form-control" placeholder="请输入价格" id="bookPrice" name="price">
</div>
<div class="form-group">
<label for="bookPublisher">出版社</label>
<input type="text" id="bookPublisher" class="form-control" placeholder="请输入图书出版社" name="publish" />
</div>
<div class="form-group">
<label for="bookStatus">图书状态</label>
<select class="custom-select" id="bookStatus" name="status">
<option value="1" selected>可借阅</option>
<option value="2">不可借阅</option>
</select>
</div>
<div class="form-group" style="text-align: right">
<button type="button" class="btn btn-info btn-lg" onclick="add()">确定</button>
<button type="button" class="btn btn-secondary btn-lg" onclick="javascript:history.back()">返回</button>
</div>
</form>
</div>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script>
function add() {
alert("添加成功");
location.href = "book_list.html";
}
</script>
</body>
</html><!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>图书列表展示</title>
<link rel="stylesheet" href="css/bootstrap.min.css">
<link rel="stylesheet" href="css/list.css">
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript" src="js/bootstrap.min.js"></script>
<script src="js/jq-paginator.js"></script>
</head>
<body>
<div class="bookContainer">
<h2>图书列表展示</h2>
<div class="navbar-justify-between">
<div>
<button class="btn btn-outline-info" type="button" onclick="location.href='book_add.html'">添加图书</button>
<button class="btn btn-outline-info" type="button" onclick="batchDelete()">批量删除</button>
</div>
</div>
<table>
<thead>
<tr>
<td>选择</td>
<td class="width100">图书ID</td>
<td>书名</td>
<td>作者</td>
<td>数量</td>
<td>定价</td>
<td>出版社</td>
<td>状态</td>
<td class="width200">操作</td>
</tr>
</thead>
<tbody>
<tr>
<td><input type="checkbox" name="selectBook" value="1" id="selectBook" class="book-select"></td>
<td>1</td>
<td>大秦帝国第一册</td>
<td>我是作者</td>
<td>23</td>
<td>33.00</td>
<td>北京出版社</td>
<td>可借阅</td>
<td>
<div class="op">
<a href="book_update.html?bookId=1">修改</a>
<a href="javascript:void(0)" onclick="deleteBook(1)">删除</a>
</div>
</td>
</tr>
<tr>
<td><input type="checkbox" name="selectBook" value="1" id="selectBook" class="book-select"></td>
<td>2</td>
<td>大秦帝国第二册</td>
<td>我是作者</td>
<td>23</td>
<td>33.00</td>
<td>北京出版社</td>
<td>可借阅</td>
<td>
<div class="op">
<a href="book_update.html?bookId=2">修改</a>
<a href="javascript:void(0)" onclick="deleteBook(2)">删除</a>
</div>
</td>
</tr>
<tr>
<td><input type="checkbox" name="selectBook" value="1" id="selectBook" class="book-select"></td>
<td>3</td>
<td>大秦帝国第三册</td>
<td>我是作者</td>
<td>23</td>
<td>33.00</td>
<td>北京出版社</td>
<td>可借阅</td>
<td>
<div class="op">
<a href="book_update.html?bookId=3">修改</a>
<a href="javascript:void(0)" onclick="deleteBook(3)">删除</a>
</div>
</td>
</tr>
<tr>
<td><input type="checkbox" name="selectBook" value="1" id="selectBook" class="book-select"></td>
<td>4</td>
<td>大秦帝国第四册</td>
<td>我是作者</td>
<td>23</td>
<td>33.00</td>
<td>北京出版社</td>
<td>可借阅</td>
<td>
<div class="op">
<a href="book_update.html?bookId=4">修改</a>
<a href="javascript:void(0)" onclick="deleteBook(4)">删除</a>
</div>
</td>
</tr>
</tbody>
</table>
<div class="demo">
<ul id="pageContainer" class="pagination justify-content-center"></ul>
</div>
<script>
getBookList();
function getBookList() {
$.ajax({
type: "get",
url: "/book/getList",
success: function(books){
var finalHtml = "";
for(var book of books){
finalHtml += '<tr>';
finalHtml += '<td><input type="checkbox" name="selectBook" value="'+book.bookId+'" id="selectBook" class="book-select"></td>';
finalHtml += '<td>'+book.bookId+'</td>';
finalHtml += '<td>'+book.bookName+'</td>';
finalHtml += '<td>'+book.author+'</td>';
finalHtml += '<td>'+book.num+'</td>';
finalHtml += '<td>'+book.price+'</td>';
finalHtml += '<td>'+book.publish+'</td>';
finalHtml += '<td>'+book.statusCN+'</td>';
finalHtml += '<td><div class="op">';
finalHtml += '<a href="book_update.html?bookId='+book.bookId+'">修改</a>';
finalHtml += '<a href="javascript:void(0)" onclick="deleteBook('+book.bookId+')">删除</a>';
finalHtml += '</div></td></tr>';
}
$("tbody").html(finalHtml);
}
});
}
//翻页信息
$("#pageContainer").jqPaginator({
totalCounts: 100, //总记录数
pageSize: 10, //每页的个数
visiblePages: 5, //可视页数
currentPage: 1, //当前页码
first: '<li class="page-item"><a class="page-link">首页</a></li>',
prev: '<li class="page-item"><a class="page-link" href="javascript:void(0);">上一页<\/a><\/li>',
next: '<li class="page-item"><a class="page-link" href="javascript:void(0);">下一页<\/a><\/li>',
last: '<li class="page-item"><a class="page-link" href="javascript:void(0);">最后一页<\/a><\/li>',
page: '<li class="page-item"><a class="page-link" href="javascript:void(0);">{{page}}<\/a><\/li>',
//页面初始化和页码点击时都会执行
onPageChange: function (page, type) {
console.log("第"+page+"页, 类型:"+type);
}
});
function deleteBook(id) {
var isDelete = confirm("确认删除?");
if (isDelete) {
//删除图书
alert("删除成功");
}
}
function batchDelete() {
var isDelete = confirm("确认批量删除?");
if (isDelete) {
//获取复选框的id
var ids = [];
$("input:checkbox[name='selectBook']:checked").each(function () {
ids.push($(this).val());
});
console.log(ids);
alert("批量删除成功");
}
}
</script>
</div>
</body>
</html><!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>修改图书</title>
<link rel="stylesheet" href="css/bootstrap.min.css">
<link rel="stylesheet" href="css/add.css">
</head>
<body>
<div class="container">
<div class="form-inline">
<h2 style="text-align: left; margin-left: 10px;"><svg xmlns="http://www.w3.org/2000/svg" width="40"
fill="#17a2b8" class="bi bi-book-half" viewBox="0 0 16 16">
<path
d="M8.5 2.687c.654-.689 1.782-.886 3.112-.752 1.234.124 2.503.523 3.388.893v9.923c-.918-.35-2.107-.692-3.287-.81-1.094-.111-2.278-.039-3.213.492V2.687zM8 1.783C7.015.936 5.587.81 4.287.94c-1.514.153-3.042.672-3.994 1.105A.5.5 0 0 0 0 2.5v11a.5.5 0 0 0 .707.455c.882-.4 2.303-.881 3.68-1.02 1.409-.142 2.59.087 3.223.877a.5.5 0 0 0 .78 0c.633-.79 1.814-1.019 3.222-.877 1.378.139 2.8.62 3.681 1.02A.5.5 0 0 0 16 13.5v-11a.5.5 0 0 0-.293-.455c-.952-.433-2.48-.952-3.994-1.105C10.413.809 8.985.936 8 1.783z" />
</svg>
<span>修改图书</span>
</h2>
</div>
<form id="updateBook">
<input type="hidden" class="form-control" id="bookId" name="id">
<div class="form-group">
<label for="bookName">图书名称:</label>
<input type="text" class="form-control" id="bookName" name="bookName">
</div>
<div class="form-group">
<label for="bookAuthor">图书作者</label>
<input type="text" class="form-control" id="bookAuthor" name="author"/>
</div>
<div class="form-group">
<label for="bookStock">图书库存</label>
<input type="text" class="form-control" id="bookStock" name="count"/>
</div>
<div class="form-group">
<label for="bookPrice">图书定价：</label>
<input type="number" class="form-control" id="bookPrice" name="price">
</div>
<div class="form-group">
<label for="bookPublisher">出版社</label>
<input type="text" id="bookPublisher" class="form-control" name="publish"/>
</div>
<div class="form-group">
<label for="bookStatus">图书状态</label>
<select class="custom-select" id="bookStatus" name="status">
<option value="1" selected>可借阅</option>
<option value="2">不可借阅</option>
</select>
</div>
<div class="form-group" style="text-align: right">
<button type="button" class="btn btn-info btn-lg" onclick="update()">确定</button>
<button type="button" class="btn btn-secondary btn-lg" onclick="javascript:history.back()">返回</button>
</div>
</form>
</div>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script>
function update() {
alert("更新成功");
location.href = "book_list.html"
}
</script>
</body>
</html><!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="css/bootstrap.min.css">
<link rel="stylesheet" href="css/login.css">
<script type="text/javascript" src="js/jquery.min.js"></script>
</head>
<body>
<div class="container-login">
<div class="container-pic">
<img src="pic/computer.png" width="350px">
</div>
<div class="login-dialog">
<h3>登陆</h3>
<div class="row">
<span>用户名</span>
<input type="text" name="userName" id="userName" class="form-control">
</div>
<div class="row">
<span>密码</span>
<input type="password" name="password" id="password" class="form-control">
</div>
<div class="row">
<button type="button" class="btn btn-info btn-lg" onclick="login()">登录</button>
</div>
</div>
</div>
<script src="js/jquery.min.js"></script>
<script>
function login() {
$.ajax({
type:"POST",
URL:"/user/login",
data:{
name: $("#userName").val(),
password: $("#password").val()
},
success:function(result){
if(result){
//账号密码正确
location.href = "book_list.html";
}else {
alert("账号或密码错误");
}
}
});
//location.href = "book_list.html";
}
</script>
</body>
</html>后端代码：
首先我们创建图书类BookInfo
@Data
public class BookInfo {
private Integer bookId;
private String bookName;
private String author;
private Integer num;
private BigDecimal price;
private Integer status;
private String publish;
private String statusCN;
}创建UserController实现登录验证接口
@RequestMapping("/user")
@RestController
public class userController {
@RequestMapping("/login")
public boolean login(String name, String password, HttpSession session){
if(!StringUtils.hasLength(name) || !StringUtils.hasLength(password)){
return false;
}
if("admin".equals(name) && "admin".equals(password)){
session.setAttribute("userName",name);
return true;
}
return false;
}
}创建BookController，来调用bookService，再调用BookDao，来实现图书列表
@RequestMapping("/book")
@RestController
public class BookController {
@Autowired
private BookService bookService;
@RequestMapping("/getList")
public List<BookInfo> getList(){
return bookService.getList();
}@Service
public class bookService {
//bookDao是数据库访问中的一个对象，现在我们对status这个对象进行修改
@Autowired
private BookDao bookDao;
public static List<BookInfo> getList(){
List<BookInfo> bookInfos=new ArrayList<>();
for (BookInfo bookInfo:bookInfos) {
if(bookInfo.getStatus()==1){
bookInfo.setStatusCN("可借阅");
}else {
bookInfo.setStatusCN("已借出");
}
}
return bookInfos;
}
}@Repository
public class BookDao {
public List<BookInfo> macData(){
//创建一个储存图书
List<BookInfo> bookInfos=new ArrayList<>();
for (int i = 1; i <=15 ; i++) {
//找图书
BookInfo bookInfo=new BookInfo();
bookInfo.setBookId(i);
bookInfo.setBookName("图书名称"+i);
bookInfo.setAuthor("图书作者"+i);
bookInfo.setNum(new Random().nextInt(100));
bookInfo.setPrice(new BigDecimal(new Random().nextInt(100)));
bookInfo.setStatus(i%2==0?2:1);
bookInfo.setPublish("出版社"+i);
bookInfos.add(bookInfo);
}
return bookInfos;
}
}最后调用前端页面的代码
应用分层
三层架构
把整体架构分为表现层、业务逻辑层和数据层.这种分层 ⽅式也称之为"三层架构".
1.表现层:就是展⽰数据结果和接受⽤⼾指令的，是最靠近⽤⼾的⼀层；
2. 业务逻辑层:负责处理业务逻辑, ⾥⾯有复杂业务的具体实现；
3. 数据层: 负责存储和管理与应⽤程序相关的数据
这三个部分，在Spring中体现为：
应用分层的好处
1.降低层与层之间的依赖，使结构更加的明确，利于各层逻辑的复用
2.开发人员可以只关注某一层，极大地降低了开发成本和维护时间
3.更容易用新的实现替换原有的层次的实现
希望能对大家有所帮助！
