MyBatisPlus学习记录

MyBatisPlus(简称MP）是基于MyBatis框架基础上开发的增强型工具，旨在简化开发、提高效率

MyBatisPlus简介

入门案例

1. 创建新模块，选择Spring初始化，并配置模块相关基础信息
2. 选择当前模块需要使用的技术集（仅选择MySQL Driver)
3. 手动添加mp起步依赖

    <dependencies><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.1</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.2.16</version></dependency>

由于mp并未被收录到idea的系统内置配置，无法直接选择加入

4. 设置Jdbc参数( application. yml)

spring:datasource:type: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/db1username: rootpassword: "031006"

5. 制作实体类与表结构（类名与表名对应，属性名与字段名对应)

package com.example.domain;public class User {private Long id;private String name;private String password;private Integer age;private String tel;@Overridepublic String toString() {return "User{" +"id=" + id +", name='" + name + '\'' +", password='" + password + '\'' +", age=" + age +", tel='" + tel + '\'' +'}';}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getTel() {return tel;}public void setTel(String tel) {this.tel = tel;}
}

6. 定义数据接口，继承BaseMapper<User>

package com.example.dao;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.domain.User;
import org.apache.ibatis.annotations.Mapper;@Mapper
public interface UserDao extends BaseMapper<User> {
}

7. 测试类中注入dao接口，测试功能

package com.example;import com.example.dao.UserDao;
import com.example.domain.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTest
class MybatisplusApplicationTests {@Autowiredprivate UserDao userDao;@Testvoid testGetAll() {List<User> users = userDao.selectList(null);System.out.println(users);}}

运行结果为

[User{id=1, name='Tom', password='tom123', age=18, tel='181633335556'}, User{id=2, name='Jerry', password='jerry666', age=17, tel='19533336666'}, User{id=3, name='Ben', password='ben555', age=20, tel='13788889999'}, User{id=4, name='王小明', password='wxm123456', age=19, tel='19999997787'}]

MyBatisPlus概述

MyBatisPlus(简称MP）是基于MyBatis框架基础上开发的增强型工具，旨在简化开发、提高效率

官网: MyBatis-Plus MyBatis-Plus (baomidou.com)

特性

• 无侵入：只做增强不做改变，引入它不会对现有工程产生影响，如丝般顺滑
• 强大的 CRUD 操作：内置通用 Mapper、通用 Service，仅仅通过少量配置即可实现单表大部分 CRUD 操作，更有强大的条件构造器，满足各类使用需求
• 支持 Lambda 形式调用：通过 Lambda 表达式，方便的编写各类查询条件，无需再担心字段写错
• 支持主键自动生成：支持多达 4 种主键策略（内含分布式唯一 ID 生成器 - Sequence），可自由配置，完美解决主键问题
• 内置分页插件：基于 MyBatis 物理分页，开发者无需关心具体操作，配置好插件之后，写分页等同于普通 List 查询
• …

标准数据层开发

标准数据层CRUD功能

功能	MP接口
新增	int insert(T t)
删除	int deleteById(Serializable id)
修改	int UpdateById(T t)
根据id查询	T selectById(Serializable id)
查询全部	List<T> selectList()
分页查询	IPage<T> selectPage(Ipage<T> page)
按条件查询	IPage<T> selectPage(Wrapper<T> queryWrapper)

package com.example;import com.example.dao.UserDao;
import com.example.domain.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTest
class MybatisplusApplicationTests {@Autowiredprivate UserDao userDao;@Testvoid testInsert() {User user = new User();user.setAge(18);user.setName("Faiz");user.setTel("18155555555");user.setPassword("faiz555");userDao.insert(user);}@Testvoid testDelete() {userDao.deleteById(1685579916861468673L);}@Testvoid testUpdate() {User user = new User();// 只修改set好的字段user.setAge(18);user.setName("Faiz");user.setId(4L);userDao.updateById(user);}@Testvoid testGetById() {User user = userDao.selectById(2L);System.out.println(user);}@Testvoid testGetAll() {List<User> users = userDao.selectList(null);System.out.println(users);}}

lombok

Lombok，一个Java类库，提供了一组注解，简化PO30实体类开发

        <dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><scope>provided</scope></dependency></dependencies>

package com.example.domain;import lombok.*;// lombok//@Setter
//@Getter
//@ToString
//@NoArgsConstructor
//@AllArgsConstructor
@Data
public class User {private Long id;private String name;private String password;private Integer age;private String tel;}

常用注解:@Data

• 为当前实体类在编译期设置对应的get/set方法，toString方法， hashCode方法，equals方法等

分页功能

1. 设置分页拦截器作为Spring管理的bean

package com.example.config;import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class MpConfig {@Beanpublic MybatisPlusInterceptor mpIntercepter() {// 1.定义Mp拦截器MybatisPlusInterceptor mpIntercepter = new MybatisPlusInterceptor();// 2.添加具体的拦截器mpIntercepter.addInnerInterceptor(new PaginationInnerInterceptor());return mpIntercepter;}
}

2. 执行分页查询

    @Testvoid testGetByPage() {IPage page = new Page(1,2);userDao.selectPage(page,null);System.out.println("当前页码值："+page.getCurrent());System.out.println("每页显示数："+page.getSize());System.out.println("一共多少页："+page.getPages());System.out.println("一共多少条数据："+page.getTotal());System.out.println("数据："+page.getRecords());}

运行结果为：

当前页码值：1
每页显示数：2
一共多少页：2
一共多少条数据：4
数据：[User(id=1, name=Tom, password=tom123, age=18, tel=181633335556), User(id=2, name=Jerry, password=jerry666, age=17, tel=19533336666)]

开启MP的日志（输出到控制台）

spring:datasource:type: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/db1username: rootpassword: "031006"# 开启MP的日志（输出到控制台）
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

DQL编程控制

条件查询方式

MyBatisPlus将书写复杂的SQL查询条件进行了封装，使用编程的形式完成查询条件的组合

    @Testvoid testGetAll() {// 方式一，按条件查询QueryWrapper wrapper = new QueryWrapper();// age < 18wrapper.lt("age",18);List<User> users1 = userDao.selectList(wrapper);System.out.println(users1);// 方式二，lambda格式按条件查询QueryWrapper<User> wrapper2 = new QueryWrapper<>();// age < 18wrapper2.lambda().lt(User::getAge,18);List<User> users2 = userDao.selectList(wrapper);System.out.println(users2);// 方式三，lambda格式按条件查询LambdaQueryWrapper<User> lambdaQueryWrapper1 = new LambdaQueryWrapper<>();// age < 18lambdaQueryWrapper1.lt(User::getAge,18);List<User> users = userDao.selectList(lambdaQueryWrapper1);System.out.println(users);LambdaQueryWrapper<User> lambdaQueryWrapper = new LambdaQueryWrapper<>();
//        // age < 20
//        lambdaQueryWrapper.lt(User::getAge,20);
//        // age > 17
//        lambdaQueryWrapper.gt(User::getAge,17);// age < 20 && age > 17
//        lambdaQueryWrapper.lt(User::getAge,20).gt(User::getAge,17);// age < 18 || age > 20lambdaQueryWrapper.lt(User::getAge,18).or().gt(User::getAge,20);List<User> users3 = userDao.selectList(lambdaQueryWrapper);System.out.println(users3);}

null值处理

• 方式一：用if
• 方式二：

        UserQuery userQuery = new UserQuery();
//        userQuery.setAge(20);userQuery.setAge2(17);LambdaQueryWrapper<User> lambdaQueryWrapper = new LambdaQueryWrapper<>();// 先判断第一个条件是否为true,为true则连接当前条件// age < 20lambdaQueryWrapper.lt(null != userQuery.getAge(),User::getAge,userQuery.getAge());// age > 17lambdaQueryWrapper.gt(null != userQuery.getAge2(),User::getAge,userQuery.getAge2());List<User> users = userDao.selectList(lambdaQueryWrapper);System.out.println(users);

查询投影

• 查询结果包含模型类中部分属性

        // 查询投影// 方式一LambdaQueryWrapper<User> lambdaQueryWrapper = new LambdaQueryWrapper<>();lambdaQueryWrapper.select(User::getId,User::getName,User::getAge);List<User> users1 = userDao.selectList(lambdaQueryWrapper);// 方式二QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.select("id","name","age");List<User> users2 = userDao.selectList(queryWrapper);System.out.println(users1);System.out.println(users2);

• 查询结果包含模型类中未定义的属性

        // 查询投影QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.select("count(*) as count,age");queryWrapper.groupBy("age");List<Map<String, Object>> users = userDao.selectMaps(queryWrapper);System.out.println(users);

查询条件设定

• 范围匹配(> 、= . between)
• 模糊匹配(like)
• 空判定(null)
• 包含性匹配(in)
• 分组(group)
• 排序(order)
• …

eq匹配

        LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<>();lqw.eq(User::getName,"Faiz");lqw.eq(User::getPassword,"wxm123456");//        List<User> users = userDao.selectList(lqw);
//        System.out.println(users);User user = userDao.selectOne(lqw);System.out.println(user);

范围查询

        LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<>();// 范围查询 lt,le,gt,ge,eq,between// 18 <= age <20lqw.between(User::getAge,18,20);List<User> users = userDao.selectList(lqw);System.out.println(users);

模糊匹配

// 模糊匹配 like// %e%(String)
//        lqw.like(User::getName,"e");
//        // [User(id=2, name=Jerry, password=jerry666, age=17, tel=19533336666), User(id=3, name=Ben, password=ben555, age=20, tel=13788889999), User(id=6, name=Decade, password=wxmmmmm, age=19, tel=16666666666)]// %e(String)lqw.likeLeft(User::getName,"e");// [User(id=6, name=Decade, password=wxmmmmm, age=19, tel=16666666666)]// e%(String)
//        lqw.likeRight(User::getName,"e");// []List<User> users = userDao.selectList(lqw);System.out.println(users);

字段映射与表名映射

问题一:表字段与编码属性设计不同步

• 名称:@TableField

• 类型:属性注解

• 位置:模型类属性定义上方

• 作用:设置当前属性对应的数据库表中的字段关系

• 范例:

  public class User {@TableField(value="pwd")private String password;
  }
  

• 相关属性

  • value(默认):设置数据库表字段名称

问题二:编码中添加了数据库中未定义的属性

• 名称:@TableField

• 类型:属性注解

• 位置:模型类属性定义上方

• 作用:设置当前属性对应的数据库表中的字段关系

• 范例:

  public class User {@TableField(exist = false)private Integer online;
  }
  

• 相关属性

  • value:设置数据库表字段名称
  • exist:设置属性在数据库表字段中是否存在，默认为true。此属性无法与value合并使用

问题三:采用默认查询开放了更多的字段查看权限

• 名称:@TableField

• 类型:属性注解

• 位置:模型类属性定义上方

• 作用:设置当前属性对应的数据库表中的字段关系

• 范例:

  public class User {@TableField(value="pwd",select = false)private String password;
  }
  

• 相关属性

  • value:设置数据库表字段名称
  • exist:设置属性在数据库表字段中是否存在，默认为true。此属性无法与value合并使用
  • select:设置属性是否参与查询，此属性与select()映射配置不冲突

问题四:表名与编码开发设计不同步

• 名称:@TableName

• 类型:类注解

• 位置:模型类定义上方

• 作用:设置当前类对应与数据库表关系

• 范例:

  @TableName("tbl_user")
  public class User {private Long id;
  }
  

• 相关属性

  • value:设置数据库表名称

package com.example.domain;import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.*;// lombok//@Setter
//@Getter
//@ToString
//@NoArgsConstructor
//@AllArgsConstructor
@Data
@TableName("tbl_user")
public class User {private Long id;private String name;@TableField(value = "pwd",select = false)private String password;private Integer age;private String tel;@TableField(exist = false)private Integer online;
}

DML编程控制

Insert

id生成策略

不同的表应用不同的id生成策略

• 日志:自增（ 1,2,3,4，…
• 购物订单:特殊规则（ FQ23948AK3843)
• 外卖单:关联地区日期等信息（ 10 04 20200314 34 91)
• 关系表:可省略id
• …

id生成策略控制

• 名称:@TableId
• 类型:属性注解
• 位置:模型类中用于表示主键的属性定义上方
• 作用:设置当前类中主键属性的生成策略·范例:

public class User {@TableId(type = IdType.AUTO)private Long id;
}

• 相关属性
  • value:设置数据库主键名称
  • type:设置主键属性的生成策略，值参照IdType枚举值
• AUTO(0)∶使用数据库id自增策略控制id生成
• NONE(1):不设置id生成策略
• INPUT(2):用户手工输入id
• ASSIGN_ID(3):雪花算法生成id（可兼容数值型与字符串型)
• ASSIGN_UUID(4):以UUID生成算法作为id生成策略

package com.example.domain;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.*;// lombok//@Setter
//@Getter
//@ToString
//@NoArgsConstructor
//@AllArgsConstructor
@Data
@TableName("tbl_user")
public class User {// 使用数据库定义的
//    @TableId(type = IdType.AUTO)// 自己定义  user.setId(555L);
//    @TableId(type = IdType.INPUT)// 雪花算法@TableId(type = IdType.ASSIGN_ID)private Long id;private String name;@TableField(value = "pwd",select = false)private String password;private Integer age;private String tel;@TableField(exist = false)private Integer online;
}

id生成策略全局配置

spring:datasource:type: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/db1username: rootpassword: "031006"main:banner-mode: off# 开启MP的日志（输出到控制台）
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImplglobal-config:banner: falsedb-config:id-type: assign_idtable-prefix: tbl_

Delete

多记录操作

    @Testvoid testDelete() {
//        userDao.deleteById(1685579916861468673L);List<Long> list = new ArrayList<>();list.add(1685940449313812482L);list.add(1685941696037003266L);list.add(1685942172673523714L);userDao.deleteBatchIds(list);}

逻辑删除

• 删除操作业务问题:业务数据从数据库中丢弃
• 逻辑删除:为数据设置是否可用状态字段，删除时设置状态字段为不可用状态，数据保留在数据库中

@Data
//@TableName("tbl_user")
public class User {// 使用数据库定义的
//    @TableId(type = IdType.AUTO)// 自己定义  user.setId(555L);
//    @TableId(type = IdType.INPUT)// 雪花算法
//    @TableId(type = IdType.ASSIGN_ID)private Long id;private String name;@TableField(value = "pwd",select = false)private String password;private Integer age;private String tel;@TableField(exist = false)private Integer online;// 逻辑删除字段,标记当前记录是否被删除@TableLogic(value = "0",delval = "1")private Integer deleted;
}

    @Testvoid testDelete() {userDao.deleteById(1);
//        List<Long> list = new ArrayList<>();
//        list.add(1685940449313812482L);
//        list.add(1685941696037003266L);
//        list.add(1685942172673523714L);
//        userDao.deleteBatchIds(list);}

运行结果为：

Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter.
Registered plugin: 'com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor@4277127c'
Property 'mapperLocations' was not specified.
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6c075e9d] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@2c06b113] will not be managed by Spring
==>  Preparing: UPDATE tbl_user SET deleted=1 WHERE id=? AND deleted=0
==> Parameters: 1(Integer)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6c075e9d]

查询操作

    @Testvoid testDelete() {
//        userDao.deleteById(1);userDao.selectList(null);
//        List<Long> list = new ArrayList<>();
//        list.add(1685940449313812482L);
//        list.add(1685941696037003266L);
//        list.add(1685942172673523714L);
//        userDao.deleteBatchIds(list);}

结果为

Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter.
Registered plugin: 'com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor@20f6f88c'
Property 'mapperLocations' was not specified.
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@8fcc534] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@16681017] will not be managed by Spring
==>  Preparing: SELECT id,name,age,tel,deleted FROM tbl_user WHERE deleted=0
==> Parameters: 
<==    Columns: id, name, age, tel, deleted
<==        Row: 2, Jerry, 17, 19533336666, 0
<==        Row: 3, Ben, 20, 13788889999, 0
<==        Row: 4, Faiz, 18, 19999997787, 0
<==        Row: 5, Build, 21, 17569932244, 0
<==        Row: 6, Decade, 19, 16666666666, 0
<==        Row: 7, Exaid, 18, 19155555555, 0
<==        Row: 111, Exaid, 18, 19155555555, 0
<==        Row: 555, Exaid, 18, 19155555555, 0
<==      Total: 8
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@8fcc534]

注意：

==> Preparing: SELECT id,name,age,tel,deleted FROM tbl_user WHERE deleted=0

配置的方式

spring:datasource:type: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/db1username: rootpassword: "031006"main:banner-mode: off# 开启MP的日志（输出到控制台）
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImplglobal-config:banner: falsedb-config:id-type: assign_idtable-prefix: tbl_logic-delete-field: deletedlogic-not-delete-value: 0logic-delete-value: 1

update

乐观锁

1. 数据库表中添加锁标记字段
2. 实体类中添加对应字段，并设定当前字段为逻辑删除标记字段

@Data
//@TableName("tbl_user")
public class User {// 使用数据库定义的
//    @TableId(type = IdType.AUTO)// 自己定义  user.setId(555L);
//    @TableId(type = IdType.INPUT)// 雪花算法
//    @TableId(type = IdType.ASSIGN_ID)private Long id;private String name;@TableField(value = "pwd",select = false)private String password;private Integer age;private String tel;@TableField(exist = false)private Integer online;// 逻辑删除字段,标记当前记录是否被删除
//    @TableLogic(value = "0",delval = "1")private Integer deleted;@Versionprivate Integer version;
}

3. 配置乐观锁拦截器实现锁机制对应的动态SQL语句拼装

@Configuration
public class MpConfig {@Beanpublic MybatisPlusInterceptor mpIntercepter() {// 1.定义Mp拦截器MybatisPlusInterceptor mpIntercepter = new MybatisPlusInterceptor();// 2.添加具体的拦截器mpIntercepter.addInnerInterceptor(new PaginationInnerInterceptor());// 3.添加乐观锁的拦截器mpIntercepter.addInnerInterceptor(new OptimisticLockerInnerInterceptor());return mpIntercepter;}
}

4. 使用乐观锁机制在修改前必须先获取到对应数据的verion方可正常进行

    @Testvoid testUpdate() {
//        User user = new User();
//        // 只修改set好的字段
//        user.setAge(18);
//        user.setName("Faiz");
//        user.setId(4L);
//        user.setPassword("fa5555");
//        user.setVersion(1);
//        userDao.updateById(user);//        //1.先通过要修改的数id将当前数据查询出来
//        User user = userDao.selectById(4L);
//        //2.将要修改的属性逐一设置进去
//        user.setName("Faiz555");
//        userDao.updateById(user);User user = userDao.selectById(4L);  // version=3,name=Faiz555User user2 = userDao.selectById(4L);  // version=3,name=Faiz555user2.setName("Faiz666");userDao.updateById(user2);   // version=4,name=Faiz666user.setName("Faiz777");userDao.updateById(user);// 最终：version=4,name=Faiz666}

运行结果：

Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter.
Registered plugin: 'com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor@5b7c8930'
Property 'mapperLocations' was not specified.
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4a642e4b] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@32ab408e] will not be managed by Spring
==>  Preparing: SELECT id,name,age,tel,deleted,version FROM tbl_user WHERE id=? AND deleted=0
==> Parameters: 4(Long)
<==    Columns: id, name, age, tel, deleted, version
<==        Row: 4, Faiz555, 18, 19999997787, 0, 3
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4a642e4b]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7b297740] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@32ab408e] will not be managed by Spring
==>  Preparing: SELECT id,name,age,tel,deleted,version FROM tbl_user WHERE id=? AND deleted=0
==> Parameters: 4(Long)
<==    Columns: id, name, age, tel, deleted, version
<==        Row: 4, Faiz555, 18, 19999997787, 0, 3
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7b297740]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6e3dd5ce] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@32ab408e] will not be managed by Spring
==>  Preparing: UPDATE tbl_user SET name=?, age=?, tel=?, version=? WHERE id=? AND version=? AND deleted=0
==> Parameters: Faiz666(String), 18(Integer), 19999997787(String), 4(Integer), 4(Long), 3(Integer)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6e3dd5ce]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7d7ceca8] was not registered for synchronization because synchronization is not active
JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@32ab408e] will not be managed by Spring
==>  Preparing: UPDATE tbl_user SET name=?, age=?, tel=?, version=? WHERE id=? AND version=? AND deleted=0
==> Parameters: Faiz777(String), 18(Integer), 19999997787(String), 4(Integer), 4(Long), 3(Integer)
<==    Updates: 0
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7d7ceca8]Process finished with exit code 0

快速开发

代码生成器

模板:MyBatisPlus提供

数据库相关配置:读取数据库获取信息

开发者自定义配置:手工配置

1. 导入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.5.1</version></parent><groupId>com.itheima</groupId><artifactId>mybatisplus_04_generator</artifactId><version>0.0.1-SNAPSHOT</version><properties><java.version>1.8</java.version></properties><dependencies><!--spring webmvc--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--mybatisplus--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.1</version></dependency><!--druid--><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.16</version></dependency><!--mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><!--test--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.12</version></dependency><!--代码生成器--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.4.1</version></dependency><!--velocity模板引擎--><dependency><groupId>org.apache.velocity</groupId><artifactId>velocity-engine-core</artifactId><version>2.3</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

2. 创建代码生成器对象，执行生成代码操作

public class CodeGenerator {public static void main(String[] args) {//1.获取代码生成器的对象AutoGenerator autoGenerator = new AutoGenerator();//设置数据库相关配置DataSourceConfig dataSource = new DataSourceConfig();dataSource.setDriverName("com.mysql.cj.jdbc.Driver");dataSource.setUrl("jdbc:mysql://localhost:3306/db1?serverTimezone=UTC");dataSource.setUsername("root");dataSource.setPassword("031006");autoGenerator.setDataSource(dataSource);//设置全局配置GlobalConfig globalConfig = new GlobalConfig();globalConfig.setOutputDir(System.getProperty("user.dir")+"/src/main/java");    //设置代码生成位置globalConfig.setOpen(false);    //设置生成完毕后是否打开生成代码所在的目录globalConfig.setAuthor("xlr");    //设置作者globalConfig.setFileOverride(true);     //设置是否覆盖原始生成的文件globalConfig.setMapperName("%sDao");    //设置数据层接口名，%s为占位符，指代模块名称globalConfig.setIdType(IdType.ASSIGN_ID);   //设置Id生成策略autoGenerator.setGlobalConfig(globalConfig);//设置包名相关配置PackageConfig packageInfo = new PackageConfig();packageInfo.setParent("com.example");   //设置生成的包名，与代码所在位置不冲突，二者叠加组成完整路径packageInfo.setEntity("domain");    //设置实体类包名packageInfo.setMapper("dao");   //设置数据层包名autoGenerator.setPackageInfo(packageInfo);//策略设置StrategyConfig strategyConfig = new StrategyConfig();strategyConfig.setInclude("tbl_user");  //设置当前参与生成的表名，参数为可变参数strategyConfig.setTablePrefix("tbl_");  //设置数据库表的前缀名称，模块名 = 数据库表名 - 前缀名  例如： User = tbl_user - tbl_strategyConfig.setRestControllerStyle(true);    //设置是否启用Rest风格strategyConfig.setVersionFieldName("version");  //设置乐观锁字段名strategyConfig.setLogicDeleteFieldName("deleted");  //设置逻辑删除字段名strategyConfig.setEntityLombokModel(true);  //设置是否启用lombokautoGenerator.setStrategy(strategyConfig);//2.执行生成操作autoGenerator.execute();}
}