【JavaEE】MyBatis 综合练习（图书管理系统）

一、数据库表

我们使用两张表，一张用户表uset_test来记录登录的用户信息，一张图书表book_test记录图书信息。

-- 创建数据库
DROP DATABASE IF EXISTS book_test;
CREATE DATABASE book_test DEFAULT CHARACTER SET utf8mb4;use book_test;-- 用户表 
DROP TABLE IF EXISTS user_info;
CREATE TABLE user_info (`id` INT NOT NULL AUTO_INCREMENT,`user_name` VARCHAR ( 128 ) NOT NULL,`password` VARCHAR ( 128 ) NOT NULL,`delete_flag` TINYINT ( 4 ) NULL DEFAULT 0,`create_time` DATETIME DEFAULT now(),`update_time` DATETIME DEFAULT now() ON UPDATE now(),
PRIMARY KEY ( `id` ),
UNIQUE INDEX `user_name_UNIQUE` ( `user_name` ASC )) ENGINE = INNODB DEFAULT 
CHARACTER 
SET = utf8mb4 COMMENT = '用户表';-- 图书表 
DROP TABLE IF EXISTS book_info;
CREATE TABLE `book_info` (`id` INT ( 11 ) NOT NULL AUTO_INCREMENT,`book_name` VARCHAR ( 127 ) NOT NULL,`author` VARCHAR ( 127 ) NOT NULL,`count` INT ( 11 ) NOT NULL,`price` DECIMAL (7,2 ) NOT NULL,`publish` VARCHAR ( 256 ) NOT NULL,`status` TINYINT ( 4 ) DEFAULT 1 COMMENT '0-无效, 1-正常, 2-不允许借阅',`create_time` DATETIME DEFAULT now(),`update_time` DATETIME DEFAULT now() ON UPDATE now(),
PRIMARY KEY ( `id` ) 
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4;
-- 初始化数据 
INSERT INTO user_info ( user_name, PASSWORD ) VALUES ( "admin", "admin" );
INSERT INTO user_info ( user_name, PASSWORD ) VALUES ( "zhangsan", "123456" );
-- 初始化图书数据 
INSERT INTO `book_info` (book_name,author,count, price, publish) 
VALUES ('活着', '余华', 29, 22.00, '北京文艺出版社');
INSERT INTO `book_info` (book_name,author,count, price, publish) 
VALUES ('平凡的世界', '路遥', 5, 98.56, '北京十月文艺出版社');
INSERT INTO `book_info` (book_name,author,count, price, publish) 
VALUES ('三体', '刘慈欣', 9, 102.67, '重庆出版社');
INSERT INTO `book_info` (book_name,author,count, price, publish) 
VALUES ('金字塔原理', '麦肯锡', 16, 178.00, '民主与建设出版社');

二、引入依赖：

引入MyBatis配置：
记得修改为自己的数据库名和密码。

spring:application:name: librarydatasource:url: jdbc:mysql://127.0.0.1:3306/book_test?characterEncoding=utf8&useSSL=falseusername: rootpassword: 1234driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:configuration:map-underscore-to-camel-case: true #配置驼峰自动转换log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #打印sql语句mapper-locations: classpath:dao/*.xml

三、Model创建

在model包路径下，创建用户表和图书表对应的类。
用户类：

package com.example.library.model;import lombok.Data;import java.util.Date;
@Data
public class UserInfo {private Integer id;private String userName;private String password;private Integer deleteFlag;private Date createTime;private Date updateTime;
}

图书类：

package com.example.library.model;import lombok.Data;import java.math.BigDecimal;
import java.util.Date;@Data
public class BookInfo {//图书IDprivate Integer id;//书名private String bookName;//作者private String author;//数量private Integer count;//定价private BigDecimal price;//出版社private String publish;//状态 0-⽆效 1-允许借阅 2-不允许借阅private Integer status;private String statusCN;//创建时间private Date createTime;//更新时间private Date updateTime;}

四、用户登录

前后端交互约定：

[请求]
/user/login
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
[参数]
name=zhangsan&password=123456
[响应]
true //账号密码验证正确, 否则返回false

controller层代码：

• 在去数据库查询之前，我们要先校验穿的参数是否合法，不为空
• 数据库查询后，要看的到的是不是空值，防止空指针异常
• 最后校验

package com.example.library.controller;import com.example.library.model.UserInfo;
import com.example.library.service.UserInfoService;
import jakarta.servlet.http.HttpSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RequestMapping("/user")
@RestController
public class LoginController {@Autowiredprivate UserInfoService userInfoService;@RequestMapping("/login")public Boolean login(String userName, String password, HttpSession session) {//校验参数if(!StringUtils.hasLength(userName)|| !StringUtils.hasLength(password) ) {return false;}//查询用户UserInfo userInfo = userInfoService.selectByName(userName);if(null == userInfo) return false;if(userInfo.getPassword().equals(password)) {session.setAttribute("userName",userName);return true;}return false;}
}

Service层代码：

• 这一层代码只需要简单调用数据持久层代码即可。

package com.example.library.service;import com.example.library.dao.UserInfoDao;
import com.example.library.model.UserInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class UserInfoService {@Autowiredprivate UserInfoDao userInfoDao;public UserInfo selectByName(String userName) {return userInfoDao.selectByName(userName);}
}

dao层：

• 简单根据名字条件查询一下，因为数据量小直接使用的 * 。

package com.example.library.dao;import com.example.library.model.UserInfo;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;@Mapper
public interface UserInfoDao {@Select("select * from user_info where  user_name  = #{userName}")UserInfo selectByName(String userName);}

前端代码：
login_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: {userName: $("#userName").val(),password: $("#password").val()},success: function(result){if(result === true){//账号密码正确location.href = "book_list.html?currentPage=1";}else {alert("账号或密码错误");}}});// location.href = "book_list.html";}
</script>
</body></html>

五、添加图书

前后端接口：

[请求]
/book/addBook
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
[参数]
bookName=图书1&author=作者1&count=23&price=36&publish=出版社1&status=1
[响应]
“” //失败信息, 成功时返回空字符串

controller层代码：

• 我们在前端传给我们对象后，要根据我们设定的数据库的参数类型及条件，进行相应的判空以及超出条件。
• 在添加图书前我们打印日志，出现异常时也打印日志。

package com.example.library.controller;import com.example.library.model.BookInfo;
import com.example.library.service.BookService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.math.BigDecimal;
import java.util.List;
@Slf4j
@RequestMapping("/book")
@RestController
@Component
public class BookController {@Autowiredprivate BookService bookService;@RequestMapping("/getList")public List<BookInfo> getList() {return bookService.getList();}@RequestMapping("/addBook")public String addBook(BookInfo bookInfo) {log.info("添加图书: " + bookInfo);if(null == bookInfo) return "不能为空";if(!StringUtils.hasLength(bookInfo.getBookName()) || bookInfo.getBookName().length() > 127) return "图书名不合规";if(!StringUtils.hasLength(bookInfo.getAuthor()) || bookInfo.getAuthor().length() > 127)  return "图书作者不合规";if(null == bookInfo.getCount() || bookInfo.getCount() < 0) return "余量不合规";if(null == bookInfo.getPrice() || bookInfo.getPrice().compareTo(new BigDecimal(0)) <= 0) return "价格不合规";if(!StringUtils.hasLength(bookInfo.getPublish()) || bookInfo.getPublish().length() > 127) return "出版社不合规";if(null == bookInfo.getStatus()|| (0 != bookInfo.getStatus().compareTo(1) && 0 != bookInfo.getStatus().compareTo(2))) return "状态不合规";try {bookService.addBook(bookInfo);return "";} catch (Exception e) {log.error("添加图书错误: " + e);return "添加图书错误";}}
}

Service层：

• 直接简单调用dao层代码即可。

package com.example.library.service;import com.example.library.dao.BookDao;
import com.example.library.model.BookInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;import java.util.ArrayList;
import java.util.List;@Service
public class BookService {@AutowiredBookDao bookDao ;//插入一行图书public void addBook(BookInfo bookInfo) {bookDao.addBook(bookInfo);}}

dao层：

• 根据条件插入即可。

package com.example.library.dao;import com.example.library.model.BookInfo;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Service;import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;@Mapper
public interface BookDao {@Insert("insert into book_info (book_name, author, count, price, publish, status) " +"values (#{bookName}, #{author}, #{count}, #{price}, #{publish}, #{status});")Integer addBook(BookInfo bookInfo);}

前端代码：
book_add.html

<!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"><pathd="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() {//前端应该进行参数校验, 此处省略//提交请求到后端$.ajax({type: "post",url: "/book/addBook",data: $("#addBook").serialize(),success: function(result){if(result== ""){//添加图书成功location.href = "book_list.html";}else {//失败alert(result);}}});}
</script>
</body></html>

六、图书列表

前后端接口：

[请求]
/book/getListByPage?currentPage=1&pageSize=10
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
[参数]
[响应]
Content-Type: application/json
{"total": 25,"records": [{"id": 25,"bookName": "图书21","author": "作者2","count": 29,"price": 22.00,"publish": "出版社1","status": 1,"statusCN": "可借阅"}, {......} ]
}

由于我们要使用分页查询，所以我们要将每一次查询的页数和每页的数据数，都要当成参数传给后端。
后端返回的是当前的图书总数量，和当前的页下的图书。
所以我们将请求和响应都封装起来，在响应中我们把请求也作为成员，以便前端拿取参数。

响应：

package com.example.library.model;import lombok.Data;import java.util.List;@Data
public class PageResult <T>{private Integer total;private List<T> records;private PageRequest pageRequest;
}

请求：

• 我们在使用limit setoff传参的时候，第一个传的数字是当前页开始的前一个在的位置，所以我们直接在这个类中进行计算，避免在数据持久层进行计算。

package com.example.library.model;import lombok.Data;@Data
public class PageRequest {private int currentPage = 1;private int pageSize = 10;private int offset;public Integer getOffset() {return pageSize * (currentPage-1);}
}

controller层代码：

    @RequestMapping("/getListByPage")public PageResult<BookInfo> getListByPage(PageRequest pageRequest) {//参数校验if(null == pageRequest) return null;if(pageRequest.getPageSize() <= 0 || pageRequest.getCurrentPage() <= 0) return null;PageResult<BookInfo> request = bookService.getListByPage(pageRequest);return request;}

Service层代码：
因为我们要根据图书的状态，反映图书可不可借阅的属性，由于是一一对应的关系，所以我们使用枚举类封装一下。
枚举类：

• lombok的@Data注解是不能对枚举类使用的。

package com.example.library.enums;public enum BookStatusEnum {DELETE(0 , "无效"),NORMAL(1,"可借阅"),FORBIDDEN(2,"不可借阅");public static String getStatusByCode(int code) {switch (code) {case 1: return NORMAL.getDesc();case 2: return FORBIDDEN.getDesc();case 0: return DELETE.getDesc();default: return null;}}private int code;private String desc;BookStatusEnum(int code, String desc) {this.code = code;this.desc = desc;}public int getCode() {return code;}public void setCode(int code) {this.code = code;}BookStatusEnum() {}public String getDesc() {return desc;}public void setDesc(String desc) {this.desc = desc;}
}

• 调用dao层的方法，以及对状态映射即可。

    public PageResult<BookInfo> getListByPage(PageRequest pageRequest) {List<BookInfo> bookInfos = bookDao.getListByPage(pageRequest);//对状态进行映射for (BookInfo x:bookInfos) {x.setStatusCN(BookStatusEnum.getStatusByCode(x.getStatus()));}PageResult<BookInfo> result = new PageResult<>();//图书总数result.setTotal(bookDao.count());//当前页图书result.setRecords(bookInfos);//请求，以便前端拿取参数result.setPageRequest(pageRequest);return result;}

dao层：
因为返回的响应中，既有当前页面的图书数据，又有总的图书数，那么我们需要两个查询函数来实现。

    @Select("select * from book_info where status != 0 limit #{offset},  #{pageSize}")List<BookInfo> getListByPage(PageRequest pageRequest);@Select("select count(1) from book_info where status != 0")int count();

前端代码：
book_list.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></tbody></table><div class="demo"><ul id="pageContainer" class="pagination justify-content-center"></ul></div><script>getBookList();function getBookList() {$.ajax({type: "get",url: "/book/getListByPage"+location.search ,success: function(result){if(result == null || result.records == null || result.pageRequest == null) return;var books = result.records;var finalHtml = "";for(var book of books){finalHtml += '<tr>';finalHtml += '<td><input type="checkbox" name="selectBook" value="'+book.bookId+'" id="selectBook" class="book-select"></td>';finalHtml += '<td>'+book.id+'</td>';finalHtml += '<td>'+book.bookName+'</td>';finalHtml += '<td>'+book.author+'</td>';finalHtml += '<td>'+book.count+'</td>';finalHtml += '<td>'+book.price+'</td>';finalHtml += '<td>'+book.publish+'</td>';finalHtml += '<td>'+book.statusCN+'</td>';finalHtml += '<td><div class="op">';finalHtml += '<a href="book_update.html?bookId='+book.id+'">修改</a>';finalHtml += '<a href="javascript:void(0)" onclick="deleteBook('+book.id+')">删除</a>';finalHtml += '</div></td></tr>';}$("tbody").html(finalHtml);//翻页信息$("#pageContainer").jqPaginator({totalCounts: result.total, //总记录数pageSize: 10,    //每页的个数visiblePages: 5, //可视页数currentPage: result.pageRequest.currentPage,  //当前页码first: '<li class="page-item"><a class="page-link">首页</a></li>',prev: '<li class="page-item"><a class="page-link" href="javascript:void(0);">上一页<\/a><\/li>',next: '<li class="page-item"><a class="page-link" href="javascript:void(0);">下一页<\/a><\/li>',last: '<li class="page-item"><a class="page-link" href="javascript:void(0);">最后一页<\/a><\/li>',page: '<li class="page-item"><a class="page-link" href="javascript:void(0);">{{page}}<\/a><\/li>',//页面初始化和页码点击时都会执行onPageChange: function (page, type) {if(type == "change") {location.href= "book_list.html?currentPage="+page;}}});}});}function deleteBook(id) {var isDelete = confirm("确认删除?");if (isDelete) {//删除图书alert("删除成功");}}function batchDelete() {var isDelete = confirm("确认批量删除?");if (isDelete) {//获取复选框的idvar ids = [];$("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>

七、修改图书

接口定义：
进⼊修改⻚⾯, 需要显⽰当前图书的信息:

[请求]
/book/queryBookById?bookId=25
[参数]
⽆
[响应]
{"id": 25,"bookName": "图书21","author": "作者2","count": 999,"price": 222.00,"publish": "出版社1","status": 2,"statusCN": null,"createTime": "2023-09-04T04:01:27.000+00:00","updateTime": "2023-09-05T03:37:03.000+00:00"
}

controller层：

    @RequestMapping("queryBookById")public BookInfo queryBookById(Integer bookId) {log.info("查询图书信息，图书id: "+bookId);return bookService.queryBookById(bookId);}

Service层：

    public BookInfo queryBookById(Integer bookId) {return bookDao.queryBookById(bookId);}

dao层：

    @Select("select * from book_info where status != 0 and id = #{bookId}")BookInfo queryBookById(Integer bookId);

点击修改按钮,修改图书信息，接口定义：

[请求]
/book/updateBook
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
[参数]
id=1&bookName=图书1&author=作者1&count=23&price=36&publish=出版社1&status=1
[响应]
“” //失败信息, 成功时返回空字符串

controller层：

• 参数可以为空，但是要满足数据库字段的定义

    @RequestMapping("updateBook")public String updateBook(BookInfo bookInfo) {log.info("修改图书: " + bookInfo);//校验参数,参数可以为空if(null == bookInfo) return "不能为空";if(StringUtils.hasLength(bookInfo.getBookName()) && bookInfo.getBookName().length() > 127) return "图书名不合规";if(StringUtils.hasLength(bookInfo.getAuthor()) && bookInfo.getAuthor().length() > 127)  return "图书作者不合规";if(null != bookInfo.getCount() && bookInfo.getCount() < 0) return "余量不合规";if(null != bookInfo.getPrice() && bookInfo.getPrice().compareTo(new BigDecimal(0)) <= 0) return "价格不合规";if(StringUtils.hasLength(bookInfo.getPublish()) && bookInfo.getPublish().length() > 127) return "出版社不合规";if(null != bookInfo.getStatus()&& (0 != bookInfo.getStatus().compareTo(1) && 0 != bookInfo.getStatus().compareTo(2))) return "状态不合规";try {bookService.updateBook(bookInfo);return "";}catch (Exception e) {log.error("修改图书错误："+e);return "修改图书错误";}}

servic层：

    public void updateBook(BookInfo bookInfo) {bookDao.updateBook(bookInfo);}

dao层：

• 因为我们传的参数是可以为空的，那么我们要是有动态sql来写，xml文件更适合。

    Integer updateBook(BookInfo bookInfo);

xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace = "com.example.library.dao.BookDao"><update id="updateBook">update book_info<set><if test="bookName!=null">book_name = #{bookName} ,</if><if test="author!=null">author = #{author} ,</if><if test="count!=null">count = #{count} ,</if><if test="price!=null">price = #{price} ,</if><if test="publish!=null">publish = #{publish} ,</if><if test="status!=null">status = #{status}</if></set>where id = #{id}</update>
</mapper>

前端代码：
book_update.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"><pathd="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>getBookInfo();function getBookInfo(){$.ajax({type: "get",url: "/book/queryBookById"+ location.search,success: function(bookInfo){if(bookInfo !=null ){$("#bookId").val(bookInfo.id);$("#bookName").val(bookInfo.bookName);$("#bookAuthor").val(bookInfo.author);$("#bookStock").val(bookInfo.count);$("#bookPrice").val(bookInfo.price);$("#bookPublisher").val(bookInfo.publish);$("#bookStatus").val(bookInfo.status);}}});}function update() {$.ajax({type: "post",url: "/book/updateBook",data: $("#updateBook").serialize(),success: function(result){if(result === ""){location.href = "book_list.html?currentPage=1";}else {alert(result);}}});}
</script>
</body></html>

八、删除图书

删除操作一般不是真删除，而是将表示删除的状态变成删除，在客户端不显示出来。
接口定义：

[请求]
/book/deleteBook
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
[参数]
id=1&status=0
[响应]
“” //失败信息, 成功时返回空字符串

我们调用直接调用修改的代码即可，只需要封装一下接口。
controller层：

    @RequestMapping("deleteBook")public String deleteBook(Integer bookId) {log.info("删除图书: " + bookId);BookInfo bookInfo = new BookInfo();bookInfo.setId(bookId);bookInfo.setStatusCN(BookStatusEnum.getStatusByCode(0));try {bookService.updateBook(bookInfo);return "";}catch (Exception e) {log.error("修改图书错误："+e);return "修改图书错误";}}

九、批量删除

接口定义：

[请求]
/book/batchDeleteBook
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
[参数]
[响应]
“” //失败信息, 成功时返回空字符串

controller层：

    @RequestMapping("/batchDeleteBook")public Boolean batchDeleteBook(Integer[] ids) {log.info("批量删除图书：bookIds: {}", ids);try {bookService.batchDeleteBook(ids);return true;}catch (Exception e) {log.error("删除图书错误" + e);return false;}}

Service层：

    public void batchDeleteBook(Integer[] ids) {bookDao.batchDeleteBook(ids);}

dao层：

    Integer batchDeleteBook(Integer[] ids);

xml文件：

    <update id="batchDeleteBook">update book_info set status = 0 where id in<foreach collection="ids" item="bookId" open="(" close=")" separator=",">#{bookId}</foreach></update>

前端方法：

        function batchDelete() {var isDelete = confirm("确认批量删除?");if (isDelete) {//获取复选框的idvar ids = [];$("input:checkbox[name='selectBook']:checked").each(function () {ids.push($(this).val());});console.log(ids);//批量删除$.ajax({type: "post",url: "/book/batchDeleteBook?ids="+ids,success: function (result) {if (result) {alert("删除成功");//重新刷新⻚⾯location.href = "book_list.html"}}});}}

十、强制登录

⽤⼾登录时, 我们已经把登录⽤⼾的信息存储在了Session中. 那就可以通过Session中的信息来判断⽤
⼾都是登录.

1. 如果Session中可以取到登录⽤⼾的信息, 说明⽤⼾已经登录了, 可以进⾏后续操作
2. 如果Session中取不到登录⽤⼾的信息, 说明⽤⼾未登录, 则跳转到登录⻚⾯.

我们的报错信息是很多的，我们单独使用null或者空对象是没法区分到底是什么原因造成的。所以我们将这个信息单独封装成类。

• 因为我们的状态与错误信息是一一对应的，所以封装成枚举类，
• 报错信息，在很多地方都要使用，所以我们提供方法，以便拿到

package com.example.library.model;import com.example.library.enums.ResultStatusEnum;
import lombok.Data;@Data
public class Result <T>{private ResultStatusEnum code;private String errMsg;private T data;/*** 业务执⾏成功时返回的⽅法** @param data* @return*/public static <T> Result success(T data) {Result result = new Result();result.setCode(ResultStatusEnum.SUCCESS);result.setErrMsg("");result.setData(data);return result;}/**** * 用户未登录*      **      * @param data*      * @return*/public static  Result unLogin () {Result result = new Result();result.setCode(ResultStatusEnum.UNLOGIN);result.setErrMsg("用户未登录");result.setData(null);return result;}/**** * 出错*      **      * @param String errMsg*      * @return*/public static <T> Result fail (String errMsg) {Result result = new Result();result.setCode(ResultStatusEnum.FAIL);result.setErrMsg(errMsg);return result;}
}

枚举类：

package com.example.library.enums;public enum ResultStatusEnum {SUCCESS(200),UNLOGIN(-1),FAIL(-2);private int code;public int getCode() {return code;}public void setCode(int code) {this.code = code;}ResultStatusEnum(int code) {this.code = code;}
}

controller：

• 因为我们获取session时的参数，在很多地方都要使用，所以我们封装起来，以便后续更改，只需更改一处即可。

    @RequestMapping("/getListByPage")public Result getListByPage(PageRequest pageRequest, HttpSession httpSession) {//登录验证if(null == httpSession.getAttribute(Constants.SESSION_USER_KEY)) return Result.unLogin();UserInfo userInfo = (UserInfo) httpSession.getAttribute(Constants.SESSION_USER_KEY);//用户未登录if(null == userInfo || 0 >= userInfo.getId()) {return Result.unLogin();}//参数校验if(null == pageRequest) return Result.fail("参数错误");if(pageRequest.getPageSize() <= 0 || pageRequest.getCurrentPage() <= 0) return Result.fail("参数错误");PageResult<BookInfo> request = bookService.getListByPage(pageRequest);return Result.success(request);}

package com.example.library.constant;public class Constants {public static final String SESSION_USER_KEY = "session_user_info";
}

由于获取session的参数变了，那么我们在登录的方法也要相应修改。

@RequestMapping("/login")public Boolean login(String userName, String password, HttpSession session) {//校验参数if(!StringUtils.hasLength(userName)|| !StringUtils.hasLength(password) ) {return false;}//查询用户UserInfo userInfo = userInfoService.selectByName(userName);if(null == userInfo) return false;if(userInfo.getPassword().equals(password)) {session.setAttribute(Constants.SESSION_USER_KEY,userInfo);return true;}return false;}

前端的获取图书列表的方法也要变。

getBookList();function getBookList() {$.ajax({type: "get",url: "/book/getListByPage"+location.search ,success: function(result){if(result == null || result.code == "UNLOGIN" ) {alert("用户未登录，请先登录");location.href = "login.html";}if(result == null || result.data == null) return;if(result.code == "FAIL" ) {alert("参数错误");}var data = result.data;var books = data.records;var finalHtml = "";for(var book of books){finalHtml += '<tr>';finalHtml += '<td><input type="checkbox" name="selectBook" value="'+book.id+'" id="selectBook" class="book-select"></td>';finalHtml += '<td>'+book.id+'</td>';finalHtml += '<td>'+book.bookName+'</td>';finalHtml += '<td>'+book.author+'</td>';finalHtml += '<td>'+book.count+'</td>';finalHtml += '<td>'+book.price+'</td>';finalHtml += '<td>'+book.publish+'</td>';finalHtml += '<td>'+book.statusCN+'</td>';finalHtml += '<td><div class="op">';finalHtml += '<a href="book_update.html?bookId='+book.id+'">修改</a>';finalHtml += '<a href="javascript:void(0)" onclick="deleteBook('+book.id+')">删除</a>';finalHtml += '</div></td></tr>';}$("tbody").html(finalHtml);//翻页信息$("#pageContainer").jqPaginator({totalCounts: data.total, //总记录数pageSize: 10,    //每页的个数visiblePages: 5, //可视页数currentPage: data.pageRequest.currentPage,  //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) {if(type == "change") {location.href= "book_list.html?currentPage="+page;}}});}});}