xustudyxu's Blog
xu
2022-05-07
目录

瑞吉外卖-分类管理业务开发

# 瑞吉外卖-分类管理业务开发

# 效果展示

  • 管理后台

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  • 移动端

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# 公共字段自动填充

# 问题分析

前面我们已经完成了后台系统的员工管理功能开发，在新增员工时需要设置创建时间、创建人、修改时间、修改人等字段，在编辑员工时需要设置修改时间和修改人等字段。这些字段属于公共字段，也就是很多表中都有这些字段，如下:

公共字段 类型
create_time datetime
update_time datetime
create_time bigint
update_time bigint

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能不能对于这些公共字段在某个地方统一处理，来简化开发呢?答案就是使用Mybatis Plus提供的公共字段自动填充功能。

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# 代码实现

Mybatis Plus公共字段自动填充，也就是在插入或者更新的时候为指定字段赋予指定的值，使用它的好处就是可以统一对这些字段进行处理，避免了重复代码。

实现步骤:

  1. 在实体类的属性上加入@TableField注解，指定自动填充的策略
@Data
public class Employee implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    private String username;
    private String name;
    private String password;
    private String phone;
    private String sex;
    private String idNumber;//身份证号码
    private Integer status;
    @TableField(fill = FieldFill.INSERT) //插入时填充字段
    private LocalDateTime createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE) //插入和更新时填充字段
    private LocalDateTime updateTime;
    @TableField(fill = FieldFill.INSERT) //插入时填充字段
    private Long createUser;
    @TableField(fill = FieldFill.INSERT_UPDATE) //插入和更新时填充字段
    private Long updateUser;
}
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  1. 按照框架【MyBatisPlus】要求编写元数据对象处理器，在此类中统一为公共字段赋值，此类需要实现MetaObjectHandler接口
/**
 * @author frx
 * @version 1.0
 * @date 2022/5/7  19:59
 * 自定义元数据对象处理器
 */
@Component //Bean
@Slf4j
public class MyMetaObjectHandler implements MetaObjectHandler {
    /**
     * 插入操作自动填充
     * @param metaObject
     */
    @Override
    public  void insertFill(MetaObject metaObject) {
        log.info("公共字段自动填充[insert]...");
        log.info(metaObject.toString());
        metaObject.setValue("createTime", LocalDateTime.now());
        metaObject.setValue("updateTime",LocalDateTime.now());
        metaObject.setValue("createUser",new Long(1));
        metaObject.setValue("updateUser",new Long(1));
    }
    /**
     * 更新操作，自动填充
     * @param metaObject
     */
    @Override
    public void updateFill(MetaObject metaObject) {
        log.info("公共字段自动填充[update]...");
        log.info(metaObject.toString());
        metaObject.setValue("updateTime",LocalDateTime.now());
        metaObject.setValue("updateUser",new Long(1));
    }
}
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  • 新增用户小王，账号为test001,再次修改账号为test002

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# 功能完善

前面我们已经完成了公共字段自动填充功能的代码开发，但是还有一个问题没有解决，就是我们在自动填充createUser和updateUser时设置的用户id是固定值，现在我们需要改造成动态获取当前登录用户的id。

有的同学可能想到，用户登录成功后我们将用户id存入了HttpSession中，现在我从HttpSession中获取不就行了? 注意，我们在MyMetaObjectHandler类中是不能获得HttpSession对象的，所以我们需要通过其他方式来获取登录用户id。

可以使用ThreadLocal来解决此问题,它是JDK中提供的一个类。

在学习ThreadLocal之前，我们需要先确认一个事情，就是客户端发送的每次http请求，对应的在服务端都会分配一个新的线程来处理，在处理过程中涉及到下面类中的方法都属于相同的一个线程:

  1. LogincheckFilter的doFilter方法
  2. EmployeeController的update方法
  3. MyMetaObjectHandler的updateFill方法

可以在上面的三个方面中分别加入下面代码(获取当前线程id):

long id =Thread.currentThread();
log.info("线程id:{}",id);
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  • 测试修改小王账号为test003
控制台输出 
2022-05-07 20:48:42.262  INFO 4740 --- [nio-8088-exec-7] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee/login
2022-05-07 20:48:42.262  INFO 4740 --- [nio-8088-exec-7] c.frx01.reggie.filter.LoginCheckFilter   : 本次请求/employee/login不需要处理
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4f5373ec] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@2b33c436] will not be managed by Spring
==>  Preparing: SELECT id,username,name,password,phone,sex,id_number,status,create_time,update_time,create_user,update_user FROM employee WHERE (username = ?)
==> Parameters: admin(String)
<==    Columns: id, username, name, password, phone, sex, id_number, status, create_time, update_time, create_user, update_user
<==        Row: 1, admin, 管理员, e10adc3949ba59abbe56e057f20f883e, 13812312312, 1, 110101199001010047, 1, 2021-05-06 17:20:07, 2021-05-10 02:24:09, 1, 1
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4f5373ec]
2022-05-07 20:48:42.412  INFO 4740 --- [nio-8088-exec-8] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee/page
2022-05-07 20:48:42.413  INFO 4740 --- [nio-8088-exec-8] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1
2022-05-07 20:48:42.413  INFO 4740 --- [nio-8088-exec-8] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:40
2022-05-07 20:48:42.413  INFO 4740 --- [nio-8088-exec-8] c.f.r.controller.EmployeeController      : page=1,pageSize=10,name=null
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@b7652e] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@2b33c436] will not be managed by Spring
==>  Preparing: SELECT COUNT(*) FROM employee
==> Parameters: 
<==    Columns: COUNT(*)
<==        Row: 5
<==      Total: 1
==>  Preparing: SELECT id,username,name,password,phone,sex,id_number,status,create_time,update_time,create_user,update_user FROM employee ORDER BY update_time DESC LIMIT ?
==> Parameters: 10(Long)
<==    Columns: id, username, name, password, phone, sex, id_number, status, create_time, update_time, create_user, update_user
<==        Row: 1522914207132921858, test002, 小王, e10adc3949ba59abbe56e057f20f883e, 13212345678, 1, 123456789991122331, 1, 2022-05-07 20:20:19, 2022-05-07 20:48:04, 1, 1
<==        Row: 1519950622798766082, Zhangsan, 张三, e10adc3949ba59abbe56e057f20f883e, 18339981812, 1, 123456789987654321, 1, 2022-04-29 16:03:54, 2022-05-07 20:03:23, 1, 1
<==        Row: 1520694192883232769, lisi123, 李四, e10adc3949ba59abbe56e057f20f883e, 18339976721, 1, 123456789123456789, 1, 2022-05-01 17:18:43, 2022-05-04 00:03:11, 1, 1
<==        Row: 1520694004332429315, lisi, 李四, e10adc3949ba59abbe56e057f20f883e, 18339976721, 1, 123456789987654321, 1, 2022-05-01 17:17:58, 2022-05-01 17:17:58, 1, 1
<==        Row: 1, admin, 管理员, e10adc3949ba59abbe56e057f20f883e, 13812312312, 1, 110101199001010047, 1, 2021-05-06 17:20:07, 2021-05-10 02:24:09, 1, 1
<==      Total: 5
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@b7652e]
<===============================修改账号为test003输出日志==============================>
2022-05-07 20:49:33.783  INFO 4740 --- [nio-8088-exec-2] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee/1522914207132921858
2022-05-07 20:49:33.783  INFO 4740 --- [nio-8088-exec-2] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1
2022-05-07 20:49:33.783  INFO 4740 --- [nio-8088-exec-2] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:34
2022-05-07 20:49:33.784  INFO 4740 --- [nio-8088-exec-2] c.f.r.controller.EmployeeController      : 根据id查询信息...
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4c3ceca9] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@2b33c436] will not be managed by Spring
==>  Preparing: SELECT id,username,name,password,phone,sex,id_number,status,create_time,update_time,create_user,update_user FROM employee WHERE id=?
==> Parameters: 1522914207132921858(Long)
<==    Columns: id, username, name, password, phone, sex, id_number, status, create_time, update_time, create_user, update_user
<==        Row: 1522914207132921858, test002, 小王, e10adc3949ba59abbe56e057f20f883e, 13212345678, 1, 123456789991122331, 1, 2022-05-07 20:20:19, 2022-05-07 20:48:04, 1, 1
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4c3ceca9]
2022-05-07 20:49:39.414  INFO 4740 --- [nio-8088-exec-3] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee
2022-05-07 20:49:39.414  INFO 4740 --- [nio-8088-exec-3] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1
2022-05-07 20:49:39.414  INFO 4740 --- [nio-8088-exec-3] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:35
2022-05-07 20:49:39.415  INFO 4740 --- [nio-8088-exec-3] c.f.r.controller.EmployeeController      : Employee(id=1522914207132921858, username=test003, name=小王, password=e10adc3949ba59abbe56e057f20f883e, phone=13212345678, sex=1, idNumber=123456789991122331, status=1, createTime=2022-05-07T20:20:19, updateTime=2022-05-07T20:48:04, createUser=1, updateUser=1)
2022-05-07 20:49:39.415  INFO 4740 --- [nio-8088-exec-3] c.f.r.controller.EmployeeController      : 线程id为:35
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4aa76d63] was not registered for synchronization because synchronization is not active
2022-05-07 20:49:39.415  INFO 4740 --- [nio-8088-exec-3] c.f.reggie.common.MyMetaObjectHandler    : 公共字段自动填充[update]...
2022-05-07 20:49:39.415  INFO 4740 --- [nio-8088-exec-3] c.f.reggie.common.MyMetaObjectHandler    : org.apache.ibatis.reflection.MetaObject@859b481
2022-05-07 20:49:39.415  INFO 4740 --- [nio-8088-exec-3] c.f.reggie.common.MyMetaObjectHandler    : 线程id为:35
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@2b33c436] will not be managed by Spring
==>  Preparing: UPDATE employee SET username=?, name=?, password=?, phone=?, sex=?, id_number=?, status=?, create_time=?, update_time=?, create_user=?, update_user=? WHERE id=?
==> Parameters: test003(String), 小王(String), e10adc3949ba59abbe56e057f20f883e(String), 13212345678(String), 1(String), 123456789991122331(String), 1(Integer), 2022-05-07T20:20:19(LocalDateTime), 2022-05-07T20:49:39.415(LocalDateTime), 1(Long), 1(Long), 1522914207132921858(Long)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4aa76d63]
2022-05-07 20:49:39.804  INFO 4740 --- [nio-8088-exec-4] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee/page
2022-05-07 20:49:39.804  INFO 4740 --- [nio-8088-exec-4] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1
2022-05-07 20:49:39.804  INFO 4740 --- [nio-8088-exec-4] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:36
2022-05-07 20:49:39.804  INFO 4740 --- [nio-8088-exec-4] c.f.r.controller.EmployeeController      : page=1,pageSize=10,name=null
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@212ba060] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@2b33c436] will not be managed by Spring
==>  Preparing: SELECT COUNT(*) FROM employee
==> Parameters: 
<==    Columns: COUNT(*)
<==        Row: 5
<==      Total: 1
==>  Preparing: SELECT id,username,name,password,phone,sex,id_number,status,create_time,update_time,create_user,update_user FROM employee ORDER BY update_time DESC LIMIT ?
==> Parameters: 10(Long)
<==    Columns: id, username, name, password, phone, sex, id_number, status, create_time, update_time, create_user, update_user
<==        Row: 1522914207132921858, test003, 小王, e10adc3949ba59abbe56e057f20f883e, 13212345678, 1, 123456789991122331, 1, 2022-05-07 20:20:19, 2022-05-07 20:49:39, 1, 1
<==        Row: 1519950622798766082, Zhangsan, 张三, e10adc3949ba59abbe56e057f20f883e, 18339981812, 1, 123456789987654321, 1, 2022-04-29 16:03:54, 2022-05-07 20:03:23, 1, 1
<==        Row: 1520694192883232769, lisi123, 李四, e10adc3949ba59abbe56e057f20f883e, 18339976721, 1, 123456789123456789, 1, 2022-05-01 17:18:43, 2022-05-04 00:03:11, 1, 1
<==        Row: 1520694004332429315, lisi, 李四, e10adc3949ba59abbe56e057f20f883e, 18339976721, 1, 123456789987654321, 1, 2022-05-01 17:17:58, 2022-05-01 17:17:58, 1, 1
<==        Row: 1, admin, 管理员, e10adc3949ba59abbe56e057f20f883e, 13812312312, 1, 110101199001010047, 1, 2021-05-06 17:20:07, 2021-05-10 02:24:09, 1, 1
<==      Total: 5
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@212ba060]
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什么是ThreadLocal?

ThreadLocal并不是一个Thread，而是Thread的局部变量。当使用ThreadLocal维护变量时，ThreadLocal为每个使用该变量的线程提供独立的变量副本，所以每一个线程都可以独立地改变自己的副本，而不会影响其它线程所对应的副本。ThreadLocal为每个线程提供单独一份存储空间，具有线程隔离的效果，只有在线程内才能获取到对应的值，线程外则不能访问。

ThreadLocal常用方法:

  • public void set(T value)
    • 设置当前线程的线程局部变量的值
  • public T get()
    • 返回当前线程所对应的线程局部变量的值

我们可以在LoginCheckFilter的doFilter方法中获取当前登录用户id，并调用ThreadLocal的set方法来设置当前线程的线程局部变量的值（用户id)，然后在MyMetaObjectHandler的updateFill方法中调用ThreadLocal的get方法来获得当前线程所对应的线程局部变量的值（用户id)。

实现步骤；

  1. 编写BaseContext工具类，基于ThreadLocal封装的工具类
  2. 在LoginCheckFilter的doFilter方法中调用BaseContext来设置当前登录用户的id
  3. 在MyMetaObjectHandler的方法中调用BaseContext获取登录用户的id
  • BaseContext工具类
/**
 * @author frx
 * @version 1.0
 * @date 2022/5/7  21:10
 * 基于ThreadLocal封装的工具类，用于保存和获取当前登录用户的id
 */
public class BaseContext {
    private static ThreadLocal<Long>  threadLocal=new ThreadLocal<>();
    public static void setCurrentId(Long id){
        threadLocal.set(id);
    }
    private static Long getCurrentId(){
        return threadLocal.get();
    }
}
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        //4.判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("employee")!=null){
            log.info("用户已登录，用户id为；{}",request.getSession().getAttribute("employee"));
            //获取Id
            Long empId= (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);
            long id=Thread.currentThread().getId();
            log.info("线程id为:{}",id);
            filterChain.doFilter(request,response);
            return;
        }
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同时也将MyMetaObjectHandler中insertFill()方法和updateFill()方法中的new Long(1)改为BaseContext.getCurrentId(empId)

  • 使用lisi账号测试修改小王账号为test004
控制台输出 
2022-05-07 21:32:58.937  INFO 9400 --- [nio-8088-exec-3] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee/1522914207132921858
2022-05-07 21:32:58.937  INFO 9400 --- [nio-8088-exec-3] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1520694004332429315
2022-05-07 21:32:58.937  INFO 9400 --- [nio-8088-exec-3] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:37
2022-05-07 21:32:58.938  INFO 9400 --- [nio-8088-exec-3] c.f.r.controller.EmployeeController      : 根据id查询信息...
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4a5646ca] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@79a23eb1] will not be managed by Spring
==>  Preparing: SELECT id,username,name,password,phone,sex,id_number,status,create_time,update_time,create_user,update_user FROM employee WHERE id=?
==> Parameters: 1522914207132921858(Long)
<==    Columns: id, username, name, password, phone, sex, id_number, status, create_time, update_time, create_user, update_user
<==        Row: 1522914207132921858, test003, 小王, e10adc3949ba59abbe56e057f20f883e, 13212345678, 1, 123456789991122331, 1, 2022-05-07 20:20:19, 2022-05-07 21:32:41, 1, 1520694004332429315
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4a5646ca]
2022-05-07 21:33:02.707  INFO 9400 --- [nio-8088-exec-5] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee
2022-05-07 21:33:02.707  INFO 9400 --- [nio-8088-exec-5] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1520694004332429315
2022-05-07 21:33:02.707  INFO 9400 --- [nio-8088-exec-5] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:39
2022-05-07 21:33:02.708  INFO 9400 --- [nio-8088-exec-5] c.f.r.controller.EmployeeController      : Employee(id=1522914207132921858, username=test004, name=小王, password=e10adc3949ba59abbe56e057f20f883e, phone=13212345678, sex=1, idNumber=123456789991122331, status=1, createTime=2022-05-07T20:20:19, updateTime=2022-05-07T21:32:41, createUser=1, updateUser=1520694004332429315)
2022-05-07 21:33:02.708  INFO 9400 --- [nio-8088-exec-5] c.f.r.controller.EmployeeController      : 线程id为:39
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6c76fe64] was not registered for synchronization because synchronization is not active
2022-05-07 21:33:02.708  INFO 9400 --- [nio-8088-exec-5] c.f.reggie.common.MyMetaObjectHandler    : 公共字段自动填充[update]...
2022-05-07 21:33:02.708  INFO 9400 --- [nio-8088-exec-5] c.f.reggie.common.MyMetaObjectHandler    : org.apache.ibatis.reflection.MetaObject@7be1cd58
2022-05-07 21:33:02.708  INFO 9400 --- [nio-8088-exec-5] c.f.reggie.common.MyMetaObjectHandler    : 线程id为:39
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@79a23eb1] will not be managed by Spring
==>  Preparing: UPDATE employee SET username=?, name=?, password=?, phone=?, sex=?, id_number=?, status=?, create_time=?, update_time=?, create_user=?, update_user=? WHERE id=?
==> Parameters: test004(String), 小王(String), e10adc3949ba59abbe56e057f20f883e(String), 13212345678(String), 1(String), 123456789991122331(String), 1(Integer), 2022-05-07T20:20:19(LocalDateTime), 2022-05-07T21:33:02.708(LocalDateTime), 1(Long), 1520694004332429315(Long), 1522914207132921858(Long)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6c76fe64]
2022-05-07 21:33:03.117  INFO 9400 --- [nio-8088-exec-4] c.frx01.reggie.filter.LoginCheckFilter   : 拦截到请求:/employee/page
2022-05-07 21:33:03.118  INFO 9400 --- [nio-8088-exec-4] c.frx01.reggie.filter.LoginCheckFilter   : 用户已登录，用户id为；1520694004332429315
2022-05-07 21:33:03.118  INFO 9400 --- [nio-8088-exec-4] c.frx01.reggie.filter.LoginCheckFilter   : 线程id为:38
2022-05-07 21:33:03.118  INFO 9400 --- [nio-8088-exec-4] c.f.r.controller.EmployeeController      : page=1,pageSize=10,name=null
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@13901309] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@79a23eb1] will not be managed by Spring
==>  Preparing: SELECT COUNT(*) FROM employee
==> Parameters: 
<==    Columns: COUNT(*)
<==        Row: 5
<==      Total: 1
==>  Preparing: SELECT id,username,name,password,phone,sex,id_number,status,create_time,update_time,create_user,update_user FROM employee ORDER BY update_time DESC LIMIT ?
==> Parameters: 10(Long)
<==    Columns: id, username, name, password, phone, sex, id_number, status, create_time, update_time, create_user, update_user
<==        Row: 1522914207132921858, test004, 小王, e10adc3949ba59abbe56e057f20f883e, 13212345678, 1, 123456789991122331, 1, 2022-05-07 20:20:19, 2022-05-07 21:33:03, 1, 1520694004332429315
<==        Row: 1519950622798766082, Zhangsan, 张三, e10adc3949ba59abbe56e057f20f883e, 18339981812, 1, 123456789987654321, 1, 2022-04-29 16:03:54, 2022-05-07 20:03:23, 1, 1
<==        Row: 1520694192883232769, lisi123, 李四, e10adc3949ba59abbe56e057f20f883e, 18339976721, 1, 123456789123456789, 1, 2022-05-01 17:18:43, 2022-05-04 00:03:11, 1, 1
<==        Row: 1520694004332429315, lisi, 李四, e10adc3949ba59abbe56e057f20f883e, 18339976721, 1, 123456789987654321, 1, 2022-05-01 17:17:58, 2022-05-01 17:17:58, 1, 1
<==        Row: 1, admin, 管理员, e10adc3949ba59abbe56e057f20f883e, 13812312312, 1, 110101199001010047, 1, 2021-05-06 17:20:07, 2021-05-10 02:24:09, 1, 1
<==      Total: 5
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@13901309]
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我们可以看出小王用户的修改用户的id为账号lisi用户的id

# 新增分类

# 需求分析

后台系统中可以管理分类信息，分类包括两种类型，分别是菜品分类和套餐分类。当我们在后台系统中添加菜品时需要选择一个菜品分类，当我们在后台系统中添加一个套餐时需要选择一个套餐分类，在移动端也会按照菜品分类和套餐分类来展示对应的菜品和套餐。

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可以在后台系统的分类管理页面分别添加菜品分类和套餐分类，如下:

image

# 数据模型

新增分类，其实就是将我们新增窗口录入的分类数据插入到category表，表结构如下:

image

# 代码开发

在开发业务功能前，先将需要用到的类和接口基本结构创建好:

  • 实体类Category
/**
 * 分类
 */
@Data
public class Category implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    //类型 1 菜品分类 2 套餐分类
    private Integer type;
    //分类名称
    private String name;
    //顺序
    private Integer sort;
    //创建时间
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createTime;
    //更新时间
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;
    //创建人
    @TableField(fill = FieldFill.INSERT)
    private Long createUser;
    //修改人
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Long updateUser;
    //是否删除
    private Integer isDeleted;
}
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  • 按照MP的要求创建Mapper接口CategoryMapper
@Mappler
public interface CategoryMapper extends BaseMapper<Category> {
}
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  • 按照MP的要求创建业务层接口CategoryService
public interface CategoryService extends IService<Category>  {
}
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  • 按照MP的要求创建业务层实现类CategoryServicelmpl
@Service
public class CategoryServiceImpl extends ServiceImpl<CategoryMapper, Category> implements CategoryService{
}
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  • 控制层CategoryController
/**
 * @author frx
 * @version 1.0
 * @date 2022/5/8  18:02
 */
@RestController
@RequestMapping("/category")
public class CategoryController {
    @Autowired
    private CategoryService categoryService;
}
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在开发代码之前，需要梳理一下整个程序的执行过程:

  1. 页面(backend/page/category/list.html)发送ajax请求，将新增分类窗口输入的数据以json形式提交到服务端
  2. 服务端Controller接收页面提交的数据并调用Service将数据进行保存
  3. Service调用Maaper操作数据库，保存数据

可以看到新增菜品分类和新增套餐分类请求的服务端地址和提交的json数据结构相同，所以服务端只需要提供一个方法统一处理即可：

image

@RestController
@RequestMapping("/category")
@Slf4j
public class CategoryController {
    @Autowired
    private CategoryService categoryService;
    /**
     * 新增分类
     * @param category
     * @return
     */
    @PostMapping
    public R<String> save(@RequestBody Category category){
        log.info("category:{}",category);
        categoryService.save(category);
        return R.success("新增分类成功");
    }
}
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  • 测试新增豫菜

image

# 分类信息分页查询

# 需求分析

系统中的分类很多的时候，如果在一个页面中全部展示出来会显得比较乱，不便于查看，所以一般的系统中都会以分页的方式来展示列表数据。

image

# 代码开发

在开发代码之前，需要梳理一下整个程序的执行过程:

  1. 页面发送ajax请求，将分页查询参数(page、pageSize)提交到服务端
  2. 服务端Controller接收页面提交的数据并调用Service查询数据
  3. Service调用Mapper操作数据库，查询分页数据
  4. Controller将查询到的分页数据响应给页面
  5. 页面接收到分页数据并通过ElementUI的Table组件展示到页面上

image

  • 编写处理器
    /**
     * 分页查询
     * @param page
     * @param pageSize
     * @return
     */
    @GetMapping("/page")
    public R<Page> page(int page,int pageSize){
        //分页构造器
        Page<Category> pageInfo=new Page<>(page,pageSize);
        //条件构造器对象
        LambdaQueryWrapper<Category> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.orderByAsc(Category::getSort);
        //进行分页查询
        categoryService.page(pageInfo,queryWrapper);
        return R.success(pageInfo);
    }
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  • 结果

image

# 删除分类

# 需求分析

在分类管理列表页面，可以对某个分类进行删除操作。需要注意的是当分类关联了菜品或者套餐时,此分类不允许删除。

image

# 代码开发

在开发代码之前，需要梳理一下整个程序的执行过程:

  1. 页面发送ajax请求，将参数(id)提交到服务器
  2. 服务器Controller接受页面提交的数据并调用Service删除数据
  3. Service调用Mapper操作数据库

image

  • 编写处理器
    /**
     * 根据id删除分类
     * @param ids
     * @return
     */
    @DeleteMapping
    public R<String> delete(Long ids){
        log.info("删除分类，id为{}",ids);
        categoryService.remove(ids);
        return R.success("分类信息删除成功");
    }
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image

# 功能完善

前面我们已经实现了根据id删除分类的功能，但是并没有检查删除的分类是否关联了菜品或者套餐，所以我们需要进行功能完善。

要完善分类删除功能，需要先准备基础的类和接口:

  1. 实体类Dish和Setmeal
  2. Mapper接口DishMapper和SetmealMapper
  3. Service接口DishService和SetmealService
  4. Service实现类DishServicelmpl和setmealServicelmpl
  • 实体类Dish
/**
 菜品
 */
@Data
public class Dish implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    //菜品名称
    private String name;
    //菜品分类id
    private Long categoryId;
    //菜品价格
    private BigDecimal price;
    //商品码
    private String code;
    //图片
    private String image;
    //描述信息
    private String description;
    //0 停售 1 起售
    private Integer status;
    //顺序
    private Integer sort;
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;
    @TableField(fill = FieldFill.INSERT)
    private Long createUser;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Long updateUser;
    //是否删除
    private Integer isDeleted;
}
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  • 实体类Setmeal
/**
 * 套餐
 */
@Data
public class Setmeal implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    //分类id
    private Long categoryId;
    //套餐名称
    private String name;
    //套餐价格
    private BigDecimal price;
    //状态 0:停用 1:启用
    private Integer status;
    //编码
    private String code;
    //描述信息
    private String description;
    //图片
    private String image;
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;
    @TableField(fill = FieldFill.INSERT)
    private Long createUser;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Long updateUser;
    //是否删除
    private Integer isDeleted;
}
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  • Mapper
@Mapper
public interface DishMapper extends BaseMapper<Dish> {
}
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@Mapper
public interface SetmealMapper extends BaseMapper<Setmeal> {
}
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  • Service
public interface DishService extends IService<Dish> {
}
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public interface SetmealService extends IService<Setmeal> {
}
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  • ServiceImpl
@Service
public class DishServiceImpl extends ServiceImpl<DishMapper, Dish> implements DishService {
}
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@Service
public class SermealServiceImpl extends ServiceImpl<SetmealMapper, Setmeal> implements SetmealService {
}
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在CategoryService接口中添加remove方法

public interface CategoryService extends IService<Category>  {
    public void remove(Long id);
}
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创建自定义异常类

public class CustomException extends RuntimeException{
    public CustomException(String message){
        super(message);
    }
}
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CategoryServiceImpl重写CategoryService接口中的remove方法

@Service
public class CategoryServiceImpl extends ServiceImpl<CategoryMapper, Category> implements CategoryService{
    @Autowired
    private DishService dishService;
    @Autowired
    private SetmealService setmealService;
    /**
     * 根据id删除分类,删除之前需要进行判断
     * @param id
     */
    @Override
    public void remove(Long id) {
        LambdaQueryWrapper<Dish> dishLambdaQueryWrapper = new LambdaQueryWrapper<>();
        //添加查询条件，根据分类ID进行查询
        dishLambdaQueryWrapper.eq(Dish::getCategoryId,id);
        int count1 = dishService.count(dishLambdaQueryWrapper);
        if(count1>0){
            //已经关联了菜品，如果已关联，抛出一个业务异常
            throw new CustomException("当前分类下关联了菜品，不能删除");
        }
        //查询当前分类是否关联了套餐，如果已经关联，抛出一个业务异常
        LambdaQueryWrapper<Setmeal> setmealLambdaQueryWrapper = new LambdaQueryWrapper<>();
        //添加查询条件，根据分类id进行查询
        setmealLambdaQueryWrapper.eq(Setmeal::getCategoryId,id);
        int count2 = setmealService.count(setmealLambdaQueryWrapper);
        if(count2>0){
            //已经关联了菜品，如果已关联，抛出一个业务异常
            throw new CustomException("当前分类下关联了套餐，不能删除");
        }
        //正常删除分类
        super.removeById(id);
    }
}
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配置全局处理自定义异常

    /**
     * 异常处理方法
     * @return
     */
    @ExceptionHandler(CustomException.class)
    public R<String> exceptionHandler(CustomException ex){
        log.error(ex.getMessage());
        return R.error(ex.getMessage());
    }
}
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编写处理器,调用remove方法

    /**
     * 根据id删除分类
     * @param id
     * @return
     */
    @DeleteMapping
    public R<String> delete(Long ids){
        log.info("删除分类，id为{}",ids);
        categoryService.remove(ids);
        return R.success("分类信息删除成功");
    }
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  • 测试删除湘菜

image

# 修改分类

# 需求分析

在分类管理列表页面点击修改按钮，弹出修改窗口，在修改窗口回显分类信息并进行修改，最后点击确定按钮完成修改操作

image

image

# 代码开发

  • 编写控制器
    /**
     * 根据id修改分类信息
     * @param category
     * @return
     */
    @PutMapping
    public R<String> update(@RequestBody Category category){
        log.info("修改分类信息:",category);
        categoryService.updateById(category);
        return R.success("修改分类信息成功");
    }
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  • 测试，将湘菜的名字改为湘菜123
==>  Preparing: UPDATE category SET name=?, sort=?, update_time=?, update_user=? WHERE id=?
==> Parameters: 湘菜123(String), 1(Integer), 2022-05-08T23:53:54.502(LocalDateTime), 1(Long), 1397844263642378242(Long)
<==    Updates: 1
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image

帮助我改善此页面 (opens new window)
#初级开发篇
上次更新: 2024年3月20日
瑞吉外卖-员工管理
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