SpringBoot整合MyBatis-Plus实现增删改查

简介

MyBatis-Plus (opens new window)的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
在这里插入图片描述

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
损耗小：启动即会自动注入基本 CURD，性能基本无损耗，直接面向对象操作
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
支持 ActiveRecord 模式：支持 ActiveRecord 形式调用，实体类只需继承 Model 类即可进行强大的 CRUD 操作
支持自定义全局通用操作：支持全局通用方法注入（ Write once, use anywhere ）
内置代码生成器：采用代码或者 Maven 插件可快速生成 Mapper 、 Model 、 Service 、 Controller 层代码，支持模板引擎，更有超多自定义配置等您来使用
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
分页插件支持多种数据库：支持 MySQL、MariaDB、Oracle、DB2、H2、HSQL、SQLite、Postgre、SQLServer 等多种数据库
内置性能分析插件：可输出 SQL 语句以及其执行时间，建议开发测试时启用该功能，能快速揪出慢查询
内置全局拦截插件：提供全表 delete 、 update 操作智能分析阻断，也可自定义拦截规则，预防误操作

SpringBoot整合MyBatis-Plus

引入maven依赖

 <dependency>
      <groupId>com.baomidou</groupId>
      <artifactId>mybatis-plus-boot-starter</artifactId>
      <version>3.4.0</version>
    </dependency>

yml配置

server:
  port: 8090

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/user?serverTimezone=UTC
    username: root
    password: etoak
    
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #开启sql日志
    call-setters-on-nulls: true
    map-underscore-to-camel-case: true

主启动类

@MapperScan("com.enbei.mapper")
@SpringBootApplication
public class App {
    public static void main( String[] args ) {
        SpringApplication.run(App.class,args);
    }
}

分页插件

@Configuration
public class MybatisPlusConfig {

    /**
     * 新的分页插件,一缓和二缓遵循mybatis的规则,需要设置 MybatisConfiguration#useDeprecatedExecutor = false 避免缓存出现问题(该属性会在旧插件移除后一同移除)
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor();
        paginationInnerInterceptor.setDbType(DbType.MYSQL);
        paginationInnerInterceptor.setOverflow(true);
        interceptor.addInnerInterceptor(paginationInnerInterceptor);
        return interceptor;
    }

    @Bean
    public ConfigurationCustomizer configurationCustomizer() {
        return configuration -> configuration.setUseDeprecatedExecutor(false);
    }
}

MyBatis-Plus单表CRUD

创建实体

@Data
@TableName("user")
@NoArgsConstructor
@AllArgsConstructor
public class User {
    /**
     * ID
     */
    @TableId
    private Long id;
    /**
     * 用户名
     */
    private String userName;
    /**
     * 年龄
     */
    private Integer age;
    /**
     * 邮箱
     */
    private String email;

}

MyBatis-Plus 通用Mapper

mapper接口

@Mapper
public interface UserMapper extends BaseMapper<User> {
}

service

@Service
public class UserService {

    @Resource
    private UserMapper userMapper;

    //添加数据
    public void insert() {
        User user = new User();
        user.setUserName("elena");
        user.setAge(21);
        user.setEmail("123@q63.com");
        userMapper.insert(user);
    }
    //根据id查询
    public void selectById() {
        userMapper.selectById(1);
    }
    //根据id更新
    public void updateById(){
        // 先查询
        User user = userMapper.selectById(1);
        user.setUserName("Jennie");
        // 再修改
        int result = userMapper.updateById(user);
        System.out.println(result);
    }

    //根据map更新
    public void selectByMap(){
        Map<String,Object> map = new HashMap<>();
        map.put("age",25);
        List<User> users = userMapper.selectByMap(map);
    }

    //根据ID批量查询
    public void selectBatchIds() {
        List<User> employees = userMapper.selectBatchIds(Arrays.asList(1, 2, 3));
        employees.forEach(System.out::println);
    }

    //根据ID删除
    public void deleteById() {
        userMapper.deleteById(1);
    }
    //根据ID批量删除
    public void deleteBatchIds() {
       userMapper.deleteBatchIds(Arrays.asList(4, 5, 6));

    }
}

MyBatis-Plus 通用Service

通用service

@Service
public class UserService extends ServiceImpl<UserMapper, User> {
    
}

如果有接口的话

public interface IUserService extends IService<User> {}

service

@Service
public class TestService {

    @Resource
    private UserService userService;



    public void save(){
        User user = new User();
        user.setUserName("jack");
        user.setAge(22);
        user.setEmail("123@q63.com");
        userService.save(user);
    }

    public void saveBatch(){
        User user1 = new User();
        user1.setUserName("jack");
        user1.setAge(22);
        user1.setEmail("123@q63.com");

        User user2 = new User();
        user2.setUserName("elena");
        user2.setAge(23);
        user2.setEmail("123@q63.com");

        List<User> list = new ArrayList();
        Collections.addAll(list,user1,user2);
        userService.saveBatch(list);
    }

    public void saveOrUpdate(){
        User user = new User();
        user.setId(1658731091639959553L);
        user.setUserName("jack");
        user.setAge(100);
        user.setEmail("123@q63.com");
        userService.saveOrUpdate(user);
       //userService.saveOrUpdateBatch(Collection<T> entityList); 与saveBatch用法一致
    }

    public void removeById(){
        userService.removeById(1658731091639959553L);
    }

    public void removeByIds(){
        userService.removeByIds(Arrays.asList(1, 2, 3));
    }


    public void removeByMap(){
        Map<String,Object> map = new HashMap<>();
        map.put("age",25);
        userService.removeByMap(map);
    }


    public void updateById(){
        User user = new User();
        user.setId(1658731091639959553L);
        user.setUserName("jack");
        user.setAge(101);
        user.setEmail("123@q63.com");
        userService.updateById(user);
    }

    public void updateBatchById(){
        User user1 = new User();
        user1.setUserName("jack");
        user1.setAge(200);
        user1.setEmail("123@q63.com");

        User user2 = new User();
        user2.setUserName("elena");
        user2.setAge(200);
        user2.setEmail("123@q63.com");

        List<User> list = new ArrayList();
        Collections.addAll(list,user1,user2);
        userService.updateBatchById(list);
    }


    public User getById(){
       return userService.getById(1);
    }

    public List<User> list(){
      return   userService.list();
    }

    public List<Map<String, Object>> listMaps(){
        return  userService.listMaps();
    }

    public List<User> page(){
         int page = 1;
         int pageSize = 2;
         Page<User> userPage = new Page<>(page, pageSize);
         Page<User> result = userService.page(userPage);
         result.getTotal();//总记录数
         result.getCurrent();//当前页
         result.getSize();//每页记录数
         result.getPages();//总页数
        return userPage.getRecords();
    }

    public int count(){
        return userService.count();
    }

}

条件构造器

通用mapper

@Service
public class UserService extends ServiceImpl<UserMapper, User> {

    @Resource
    private UserMapper userMapper;

      //查询单条数据
    public User selectOne(String name) {
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        //queryWrapper.eq("user_name","elena");
        queryWrapper.eq(!StringUtils.isEmpty(name),"user_name",name);
        return userMapper.selectOne(queryWrapper);
       // userMapper.selectOne(Wrappers.lambdaQuery(User.class).eq(User::getUserName,name));
    }
    //删除
    public void delete(String name) {
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("user_name",name);
        userMapper.delete(queryWrapper);
     //   userMapper.delete(Wrappers.lambdaQuery(User.class).eq(User::getUserName,name));
    }

    //将符合queryWrapper条件的数据更新为实体类中的数据
    public void update(String name) {
        User user = userMapper.selectById(1);
        UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
        updateWrapper.eq("user_name",name);
    //    LambdaUpdateWrapper<User> lambdaUpdateWrapper = Wrappers.lambdaUpdate(User.class).eq(User::getUserName, name);

        if (user != null){
            user.setAge(10086);
            userMapper.update(user,updateWrapper);
          //  userMapper.update(user,lambdaUpdateWrapper);
        }
    }

   //分页
    public List<User> pageList(String name) {
        int page = 1;
        int pageSize = 2;
        Page<User> userPage = new Page<>(page, pageSize);
        LambdaQueryWrapper<User> lambdaQueryWrapper = Wrappers.lambdaQuery(User.class)
                .like(User::getUserName, name)
                .eq(User::getAge,23)
                .orderByDesc(User::getId);//根据id排序
        Page<User> result = userMapper.selectPage(userPage, lambdaQueryWrapper);
        result.getTotal();//总记录数
        result.getCurrent();//当前页
        result.getSize();//每页记录数
        result.getPages();//总页数
        return userPage.getRecords();
    }

}

通用service

 @Service
public class TestService{

    @Resource
    private UserService userService;

    //查询
    public void lambdaQuery(){
        List<User> list = userService.lambdaQuery().eq(User::getAge, 18).list();
        list.forEach(System.out::println);
    }

    //修改
    public void lambdaUpdate(){
        boolean update = userService.lambdaUpdate().eq(User::getAge, 18).set(User::getAge, 31).update();
        System.out.println(update);
    }

    //删除
    public void lambdaDel(){
        boolean remove = userService.lambdaUpdate().eq(User::getAge, 18).remove();
        System.out.println(remove);
    }

}

条件构造器的其他方法

eq

eq(R column, Object val)
eq(boolean condition, R column, Object val)

等于 =
例: eq("name", "老王")—>name = '老王'

ne

ne(R column, Object val)
ne(boolean condition, R column, Object val)

不等于 <>
例: ne("name", "老王")—>name <> '老王'

gt

gt(R column, Object val)
gt(boolean condition, R column, Object val)

大于 >
例: gt("age", 18)—>age > 18

ge

ge(R column, Object val)
ge(boolean condition, R column, Object val)

大于等于 >=
例: ge("age", 18)—>age >= 18

lt

lt(R column, Object val)
lt(boolean condition, R column, Object val)

小于 <
例: lt("age", 18)—>age < 18

le

le(R column, Object val)
le(boolean condition, R column, Object val)

小于等于 <=
例: le("age", 18)—>age <= 18

between

between(R column, Object val1, Object val2)
between(boolean condition, R column, Object val1, Object val2)

BETWEEN 值1 AND 值2
例: between("age", 18, 30)—>age between 18 and 30

notBetween

notBetween(R column, Object val1, Object val2)
notBetween(boolean condition, R column, Object val1, Object val2)

NOT BETWEEN 值1 AND 值2
例: notBetween("age", 18, 30)—>age not between 18 and 30

like

like(R column, Object val)
like(boolean condition, R column, Object val)

LIKE ‘%值%’
例: like("name", "王")—>name like '%王%'

notLike

notLike(R column, Object val)
notLike(boolean condition, R column, Object val)

NOT LIKE ‘%值%’
例: notLike("name", "王")—>name not like '%王%'

likeLeft

likeLeft(R column, Object val)
likeLeft(boolean condition, R column, Object val)

LIKE ‘%值’
例: likeLeft("name", "王")—>name like '%王'

likeRight

likeRight(R column, Object val)
likeRight(boolean condition, R column, Object val)

LIKE ‘值%’
例: likeRight("name", "王")—>name like '王%'

notLikeLeft

notLikeLeft(R column, Object val)
notLikeLeft(boolean condition, R column, Object val)

NOT LIKE ‘%值’
例: notLikeLeft("name", "王")—>name not like '%王'

notLikeRight

notLikeRight(R column, Object val)
notLikeRight(boolean condition, R column, Object val)

NOT LIKE ‘值%’
例: notLikeRight("name", "王")—>name not like '王%'

isNull

isNull(R column)
isNull(boolean condition, R column)

字段 IS NULL
例: isNull("name")—>name is null

isNotNull

isNotNull(R column)
isNotNull(boolean condition, R column)

字段 IS NOT NULL
例: isNotNull("name")—>name is not null

in

in(R column, Collection<?> value)
in(boolean condition, R column, Collection<?> value)

字段 IN (value.get(0), value.get(1), …)
例: in("age",{1,2,3})—>age in (1,2,3)

in(R column, Object... values)
in(boolean condition, R column, Object... values)

字段 IN (v0, v1, …)
例: in("age", 1, 2, 3)—>age in (1,2,3)

notIn

notIn(R column, Collection<?> value)
notIn(boolean condition, R column, Collection<?> value)

字段 NOT IN (value.get(0), value.get(1), …)
例: notIn("age",{1,2,3})—>age not in (1,2,3)

notIn(R column, Object... values)
notIn(boolean condition, R column, Object... values)

字段 NOT IN (v0, v1, …)
例: notIn("age", 1, 2, 3)—>age not in (1,2,3)

inSql

inSql(R column, String inValue)
inSql(boolean condition, R column, String inValue)

字段 IN ( sql语句 )
例: inSql("age", "1,2,3,4,5,6")—>age in (1,2,3,4,5,6)
例: inSql("id", "select id from table where id < 3")—>id in (select id from table where id < 3)

notInSql

notInSql(R column, String inValue)
notInSql(boolean condition, R column, String inValue)

字段 NOT IN ( sql语句 )
例: notInSql("age", "1,2,3,4,5,6")—>age not in (1,2,3,4,5,6)
例: notInSql("id", "select id from table where id < 3")—>id not in (select id from table where id < 3)

groupBy

groupBy(R... columns)
groupBy(boolean condition, R... columns)

分组：GROUP BY 字段, …
例: groupBy("id", "name")—>group by id,name

orderByAsc

orderByAsc(R... columns)
orderByAsc(boolean condition, R... columns)

排序：ORDER BY 字段, … ASC
例: orderByAsc("id", "name")—>order by id ASC,name ASC

orderByDesc

orderByDesc(R... columns)
orderByDesc(boolean condition, R... columns)

排序：ORDER BY 字段, … DESC
例: orderByDesc("id", "name")—>order by id DESC,name DESC

orderBy

orderBy(boolean condition, boolean isAsc, R... columns)

排序：ORDER BY 字段, …
例: orderBy(true, true, "id", "name")—>order by id ASC,name ASC

having

having(String sqlHaving, Object... params)
having(boolean condition, String sqlHaving, Object... params)

HAVING ( sql语句 )
例: having("sum(age) > 10")—>having sum(age) > 10
例: having("sum(age) > {0}", 11)—>having sum(age) > 11

func

func(Consumer<Children> consumer)
func(boolean condition, Consumer<Children> consumer)

func 方法(主要方便在出现if…else下调用不同方法能不断链)
例: func(i -> if(true) {i.eq("id", 1)} else {i.ne("id", 1)})

or

or()
or(boolean condition)

拼接 OR

注意事项:

主动调用or表示紧接着下一个方法不是用and连接!(不调用or则默认为使用and连接)
例: eq("id",1).or().eq("name","老王")—>id = 1 or name = '老王'

or(Consumer<Param> consumer)
or(boolean condition, Consumer<Param> consumer)

OR 嵌套
例: or(i -> i.eq("name", "李白").ne("status", "活着"))—>or (name = '李白' and status <> '活着')

and

and(Consumer<Param> consumer)
and(boolean condition, Consumer<Param> consumer)

AND 嵌套
例: and(i -> i.eq("name", "李白").ne("status", "活着"))—>and (name = '李白' and status <> '活着')

nested

nested(Consumer<Param> consumer)
nested(boolean condition, Consumer<Param> consumer)

正常嵌套不带 AND 或者 OR
例: nested(i -> i.eq("name", "李白").ne("status", "活着"))—>(name = '李白' and status <> '活着')

apply

apply(String applySql, Object... params)
apply(boolean condition, String applySql, Object... params)

拼接 sql

注意事项:

该方法可用于数据库函数动态入参的params对应前面applySql内部的{index}部分.这样是不会有sql注入风险的,反之会有!
例: apply("id = 1")—>id = 1
例: apply("date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")—>date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")
例: apply("date_format(dateColumn,'%Y-%m-%d') = {0}", "2008-08-08")—>date_format(dateColumn,'%Y-%m-%d') = '2008-08-08'")

last

last(String lastSql)
last(boolean condition, String lastSql)

无视优化规则直接拼接到 sql 的最后

注意事项:

只能调用一次,多次调用以最后一次为准有sql注入的风险,请谨慎使用
例: last("limit 1")

exists

exists(String existsSql)
exists(boolean condition, String existsSql)

拼接 EXISTS ( sql语句 )
例: exists("select id from table where age = 1")—>exists (select id from table where age = 1)

notExists

notExists(String notExistsSql)
notExists(boolean condition, String notExistsSql)

拼接 NOT EXISTS ( sql语句 )
例: notExists("select id from table where age = 1")—>not exists (select id from table where age = 1)

SpringBoot整合MyBatis-Plus实现增删改查

简介

特性

SpringBoot整合MyBatis-Plus

MyBatis-Plus单表CRUD

MyBatis-Plus 通用Mapper

MyBatis-Plus 通用Service

条件构造器

条件构造器的其他方法

eq

ne

gt

ge

lt

le

between

notBetween

like

notLike

likeLeft

likeRight

notLikeLeft

notLikeRight

isNull

isNotNull

in

notIn

inSql

notInSql

groupBy

orderByAsc

orderByDesc

orderBy

having

func

or

and

nested

apply

last

exists

notExists

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