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mybatis-plus

雍马鲁
2023-12-01

开始配置

<dependency> //当前版本
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus</artifactId>
    <version>3.5.1</version>
</dependency>

1.连接数据库配置

#数据库连接配置
spring.datasource.username=root
spring.datasource.password=root
#mysql5~8 驱动不同driver-class-name     8需要增加时区的配置serverTimezone=UTC
#useSSL=false 安全连接
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

2.导入Pom配置文件

<dependencies>
        <!--1.数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--2.lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <!--3.mybatis-plus  版本很重要3.0.5-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

3.在主启动类添加@MapperScan注解

@MapperScan("com.xxx.mapper")

4.测试

@SpringBootTest
class MybatisPlusApplicationTests {
    //继承了BaseMapper,所有的方法都来自父类,我们也可以编写自己的扩展方法!
    @Autowired
    private UserMapper userMapper;
    @Test
    void contextLoads() {
        //参数是一个wrapper ,条件构造器,这里我们先不用 null
        List<User> userList = userMapper.selectList(null);//查询全部的用户
        userList.forEach(System.out::println);
    }
}

5.配置日志

#配置日志  log-impl:日志实现
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

注解

1.@TableName

  • 描述:表名注解,标识实体类对应的表
  • 使用位置:实体类
@TableName("sys_user")
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

2.@TableId

  • 描述:主键注解
  • 使用位置:实体类主键字段
@TableName("sys_user")
public class User {
    @TableId        		 //type IdType.NONE
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

3.@TableField

  • 描述:字段注解(非主键)
@TableName("sys_user")
public class User {
    @TableId
    private Long id;
    @TableField("nickname")
    private String name;
    private Integer age;
    private String email;
}

4.@Verison

描述:乐观锁注解、标记 @Verison 在字段

5.@TableLogic

  • 描述:表字段逻辑处理注解(逻辑删除)
属性类型必须指定默认值描述
valueString“”逻辑未删除值
delvalString“”逻辑删除值

代码生成器(新)

注意:
适用版本:mybatis-plus-generator 3.5.1 及其以上版本,对历史版本不兼容!3.5.1 以下的请参考 代码生成器旧
<dependency>  <!--注意当前包未传递依赖 MP 包,需要自己引入-->
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>最新版本</version>
</dependency>
//快速生成
FastAutoGenerator.create("url", "username", "password")
    .globalConfig(builder -> {
        builder.author("baomidou") // 设置作者
            .enableSwagger() // 开启 swagger 模式
            .fileOverride() // 覆盖已生成文件
            .outputDir("D://"); // 指定输出目录
    })
    .packageConfig(builder -> {
        builder.parent("com.baomidou.mybatisplus.samples.generator") // 设置父包名
            .moduleName("system") // 设置父包模块名
            .pathInfo(Collections.singletonMap(OutputFile.xml, "D://")); // 设置mapperXml生成路径
    })
    .strategyConfig(builder -> {
        builder.addInclude("t_simple") // 设置需要生成的表名
            .addTablePrefix("t_", "c_"); // 设置过滤表前缀
    })
    .templateEngine(new FreemarkerTemplateEngine()) // 使用Freemarker引擎模板,默认的是Velocity引擎模板
    .execute();

代码生成器(旧)

MyBatis-Plus 从 3.0.3 之后移除了代码生成器与模板引擎的默认依赖,需要手动添加相关依赖:

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>3.5.0</version>
</dependency>
<!--把下面的也加上--》

MyBatis-Plus 从 3.0.3 之前移除了代码生成器与模板引擎的默认依赖,需要手动添加相关依赖:

<!--模板引擎 依赖:mybatis-plus代码生成的时候报异常-->
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-engine-core</artifactId>
    <version>2.0</version>
</dependency>
<!--配置ApiModel在实体类中不生效-->
<dependency>
    <groupId>com.spring4all</groupId>
    <artifactId>spring-boot-starter-swagger</artifactId>
    <version>1.5.1.RELEASE</version>
</dependency>
<!--freemarker-->
<dependency>
    <groupId>org.freemarker</groupId>
    <artifactId>freemarker</artifactId>
    <version>2.3.30</version>
</dependency>
<!--beetl-->
<dependency>
    <groupId>com.ibeetl</groupId>
    <artifactId>beetl</artifactId>
    <version>3.3.2.RELEASE</version>
</dependency>
注意:
适用版本:mybatis-plus-generator 3.5.1 
//代码自动生成器
public class WskCode {
    public static void main(String[] args) {
       //我们需要构建一个代码生成器对象
        AutoGenerator mpg = new AutoGenerator();
        //怎么样去执行,配置策略
        //1、全局配置
        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir");//获取当前目录
        gc.setOutputDir(projectPath+"/mybatisplus/src/main/java");//输出到哪个目录
        gc.setAuthor("fjw");
        gc.setOpen(false);
        gc.setFileOverride(false);//是否覆盖
        gc.setServiceName("%sService");//去Service的I前缀
        gc.setIdType(IdType.AUTO);
        gc.setDateType(DateType.ONLY_DATE);
        gc.setSwagger2(true);
        mpg.setGlobalConfig(gc);
        //2、设置数据源
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setUsername("root");
        dsc.setPassword("abc123");
        dsc.setUrl("jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8");
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setDbType(DbType.MYSQL);
        mpg.setDataSource(dsc);
        //3、包的配置
        PackageConfig pc = new PackageConfig();
        pc.setModuleName("admin");
        pc.setParent("com.fjw");
        pc.setEntity("entity");
        pc.setMapper("mapper");
        pc.setService("service");
        pc.setController("controller");
        mpg.setPackageInfo(pc);
        //4、策略配置
        StrategyConfig strategy = new StrategyConfig();
        //"admin","danyuan","building","room"
        strategy.setInclude("mybatisplus");//设置要映射的表名,只需改这里即可
        strategy.setNaming(NamingStrategy.underline_to_camel);
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);
        strategy.setEntityLombokModel(true);//是否使用lombok开启注解
        strategy.setLogicDeleteFieldName("deleted");//逻辑删除的字段
        //自动填充配置
        TableFill gmtCreate = new TableFill("create_time", FieldFill.INSERT);
        TableFill gmtUpdate = new TableFill("update_time", FieldFill.INSERT_UPDATE);
        ArrayList<TableFill> tableFills = new ArrayList<>();
        tableFills.add(gmtCreate);
        tableFills.add(gmtUpdate);
        strategy.setTableFillList(tableFills);
        //乐观锁配置
        strategy.setVersionFieldName("version");
        strategy.setRestControllerStyle(true);//开启驼峰命名
        strategy.setControllerMappingHyphenStyle(true);//localhost:8080/hello_id_2
        mpg.setStrategy(strategy);
        mpg.execute();//执行
    }
}

CRUD

Insert

@Test//测试插入
public void insertTest(){
    User user = new User();
    user.setName("w");
    user.setAge(18);
    user.setEmail("12803@qq.com");
    Integer result = userMapper.insert(user); //会帮我们自动生成id
    System.out.println(result); //受影响的行数
    System.out.println(user); //通过日志发现id会自动回填
}

Update

@Test//测试更新
public void updateTest(){
    User user = new User();
    user.setId(2L);//怎么改id??
    //通过条件自动拼接动态Sql
    user.setName("root");
    user.setAge(12);
    user.setEmail("root@qq.com");
    int i = userMapper.updateById(user);//updateById,但是参数是个user
    System.out.println(i);
}

Select

@Test//通过id查询单个用户
public void testSelectById(){
    User user = userMapper.selectById(1L);
    System.out.println(user);
}

@Test//通过id查询多个用户
public void testSelectBatchIds(){
    List<User> users = userMapper.selectBatchIds(Arrays.asList(1L, 2L, 3L));
    users.forEach(System.out::println);
    //System.out.println(users);
}

@Test//通过条件查询之一  map
public void testMap(){
    HashMap<String, Object> map = new HashMap<>();
    //自定义要查询的
    map.put("name","www");
    map.put("age",18);
    List<User> users = userMapper.selectByMap(map);
    users.forEach(System.out::println);
}

Delete

@Test  //单个id
public void testDeleteById(){
    userMapper.deleteById(1359507762519068681L);
}
@Test  //多个id
public void testDeleteBatchIds(){
  userMapper.deleteBatchIds(Arrays.asList(1359507762519068675L,1359507762519068676L));
}
@Test  //多个参数
public void testD(){
    HashMap<String, Object> map = new HashMap<>();
    map.put("age","18");
    map.put("name","lol");
    userMapper.deleteByMap(map);
}

逻辑删除(无法更新修改)

旧版:

1.在数据表中增加一个deleted字段
2.实体类中添加对应属性
3.逻辑删除组件
4.逻辑删除后,就查不到,条件是deleted=0
@TableLogic//逻辑删除注解
private Integer deleted;
//逻辑删除组件
@Bean
public ISqlInjector sqlInjector(){
    return new LogicSqlInjector();
}
#配置逻辑删除  没删除的为0 删除的为1
mybatis-plus.global-config.db-config.logic-delete-value=1
mybatis-plus.global-config.db-config.logic-not-delete-value=0

新版:

mybatis-plus:
  global-config:
    db-config:
      logic-delete-field: flag # 全局逻辑删除的实体字段名(since 3.3.0,配置后可以忽略不配置步骤2)
      logic-delete-value: 1 # 逻辑已删除值(默认为 1)
      logic-not-delete-value: 0 # 逻辑未删除值(默认为 0)
@TableLogic
private Integer deleted;

分页查询

1.配置拦截器组件
2.直接使用page对象即可

旧:

 //分页插件
@Bean
public PaginationInterceptor paginationInterceptor() {
    return new PaginationInterceptor();
}

新:注意版本要求:3.4.0 版本以上

@Configuration
@MapperScan("scan.your.mapper.package")
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();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.H2));
        return interceptor;
    }

    @Bean
    public ConfigurationCustomizer configurationCustomizer() {
        return configuration -> configuration.setUseDeprecatedExecutor(false);
    }
}
@Test//测试分页查询
public void testPage(){
    //参数一current:当前页   参数二size:页面大小
    //使用了分页插件之后,所有的分页操作都变得简单了
    Page<User> page = new Page<>(2,5);
    userMapper.selectPage(page,null);
    page.getRecords().forEach(System.out::println);
    System.out.println("总页数==>"+page.getTotal());
}

主键自增

1. @TableId(type = IdType.AUTO)
    private Integer id;
2.数据库要设置自增

主键策略(Spring-Boot)

方式一:使用配置类

@Bean
public IKeyGenerator keyGenerator() {
    return new H2KeyGenerator();
}

方式二:通过 MybatisPlusPropertiesCustomizer 自定义

@Bean
public MybatisPlusPropertiesCustomizer plusPropertiesCustomizer() {
    return plusProperties -> plusProperties.getGlobalConfig().getDbConfig().setKeyGenerator(new H2KeyGenerator());
}

自定义ID生成器(Spring-Boot)

自 3.3.0 开始,默认使用雪花算法+UUID(不含中划线)

方式一:声明为 Bean 供 Spring 扫描注入

@Component
public class CustomIdGenerator implements IdentifierGenerator {
    @Override
    public Long nextId(Object entity) {
      	//可以将当前传入的class全类名来作为bizKey,或者提取参数来生成bizKey进行分布式Id调用生成.
      	String bizKey = entity.getClass().getName();
        //根据bizKey调用分布式ID生成
        long id = ....;
      	//返回生成的id值即可.
        return id;
    }
}

方式二:使用配置类

@Bean
public IdentifierGenerator idGenerator() {
    return new CustomIdGenerator();
}

方式三:通过 MybatisPlusPropertiesCustomizer 自定义

@Bean
public MybatisPlusPropertiesCustomizer plusPropertiesCustomizer() {
    return plusProperties -> plusProperties.getGlobalConfig().setIdentifierGenerator(new CustomIdGenerator());
}

自动填充

在表中增加字段:create_time,update_time

1.方式一

数据库级别
    数据类型 datetime
    默认:CURRENT_TIMESTAMP
    更新:更新操作字段可以勾选上

2.方式二

代码级别上
	1.实体类字段属性上需要增加注解
	2.编写处理器来处理这个注解即可
//字段  字段添加填充内容
@TableField(fill = FieldFill.INSERT)//value = ("create_time"),
private Date createTime;
@TableField(fill = FieldFill.INSERT_UPDATE)
private Date updateTime;

旧版:

@Slf4j//日志
@Component//丢到springboot里   一定不要忘记把处理器加到Ioc容器中!
public class MyMetaObjectHandler extends MetaObjectHandler {
    @Override//插入时的填充策略
    public void insertFill(MetaObject metaObject) {
        log.info("==start insert ······==");
        //setFieldValByName(java.lang.String fieldName, java.lang.Object fieldVal, org.apache.ibatis.reflection.MetaObject metaObject)
        this.setFieldValByName("createTIme",new Date(),metaObject);
        this.setFieldValByName("updateTime",new Date(),metaObject);
    }
    @Override//更新时的填充策略
    public void updateFill(MetaObject metaObject) {
        log.info("==start update ······==");
        this.setFieldValByName("updateTime",new Date(),metaObject);
    }
}

新版:

@Slf4j
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {

    @Override
    public void insertFill(MetaObject metaObject) {
        log.info("start insert fill ....");
        this.strictInsertFill(metaObject, "createTime", LocalDateTime.class, LocalDateTime.now()); // 起始版本 3.3.0(推荐使用)
        // 或者
        this.strictInsertFill(metaObject, "createTime", () -> LocalDateTime.now(), LocalDateTime.class); // 起始版本 3.3.3(推荐)
        // 或者
        this.fillStrategy(metaObject, "createTime", LocalDateTime.now()); // 也可以使用(3.3.0 该方法有bug)
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        log.info("start update fill ....");
        this.strictUpdateFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now()); // 起始版本 3.3.0(推荐)
        // 或者
        this.strictUpdateFill(metaObject, "updateTime", () -> LocalDateTime.now(), LocalDateTime.class); // 起始版本 3.3.3(推荐)
        // 或者
        this.fillStrategy(metaObject, "updateTime", LocalDateTime.now()); // 也可以使用(3.3.0 该方法有bug)
    }
}

乐观锁(无法更新修改)

1.给数据库中增加version字段
2.实体类加对应的字段
3.注册组件
4.测试
@Version//乐观锁version注解
private Integer version;

旧:

//扫描mapper文件夹
@MapperScan("com.wsk.mapper")//交给mybatis做的,可以让这个配置类做扫描
@EnableTransactionManagement//自动管理事务
@Configuration//配置类
public class MyBatisPlusConfig {
    //注册乐观锁插件
    @Bean
    public OptimisticLockerInterceptor optimisticLockerInterceptor(){
        return new OptimisticLockerInterceptor();
    }
}

新:注意版本要求:3.4.0 版本以上

@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
    MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
    interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
    return interceptor;
}
@Test//测试乐观锁成功
public void testOptimisticLocker1(){
    //1、查询用户信息
    User user = userMapper.selectById(1L);
    //2、修改用户信息
    user.setAge(18);
    user.setEmail("2803708553@qq.com");
    //3、执行更新操作
    userMapper.updateById(user);
}

性能分析插件

1.导入插件
2.测试使用
 //性能分析插件
@Bean
@Profile({"dev","test"})//设置dev开发、test测试 环境开启  保证我们的效率
public PerformanceInterceptor performanceInterceptor(){
    PerformanceInterceptor performanceInterceptor = new PerformanceInterceptor();
    performanceInterceptor.setMaxTime(100);//设置sql最大执行时间*ms,如果超过了则不执行
    performanceInterceptor.setFormat(true);//开启sql格式化
    return performanceInterceptor;
}
#设置开发环境
spring.profiles.active=dev
@Test
void contextLoads() {
    //参数是一个wrapper ,条件构造器,这里我们先不用 null
    //查询全部的用户
    List<User> userList = userMapper.selectList(null);
    userList.forEach(System.out::println);
}

条件构造器

eq

eq(R column, Object val)
eq(boolean condition, R column, Object val)
  • 等于 =
  • 例: eq("name", "老王")—>name = '老王'
@Test
public void testWrapper2() {
    //查询name=wsk的用户
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    wrapper.eq("name","wsk");
    //查询一个数据selectOne,若查询出多个会报错
    //Expected one result (or null) to be returned by selectOne(), but found: *
    //若出现多个结果使用list或map
    User user = userMapper.selectOne(wrapper);//查询一个数据,若出现多个结果使用list或map
    System.out.println(user);
}

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

    @Test
    public void testWrapper1() {
        //参数是一个wrapper ,条件构造器,和刚才的map对比学习!
        //查询name不为空,email不为空,age大于18的用户
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper
            .isNotNull("name")
            .isNotNull("email")
            .ge("age",18);
        List<User> userList = userMapper.selectList(wrapper);
        userList.forEach(System.out::println);
    }
    

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
@Test
public void testWrapper3() {
    //查询age在10-20之间的用户
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    wrapper.between("age", 10, 20);//区间
    Integer count = userMapper.selectCount(wrapper);//输出查询的数量selectCount
    System.out.println(count);
}

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%'
@Test
public void testWrapper4() {
    //模糊查询
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    wrapper
        .notLike("name","s")
        .likeRight("email","t");//qq%  左和右?
    List<Map<String, Object>> maps = userMapper.selectMaps(wrapper);
    maps.forEach(System.out::println);
}

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%'

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)
@Test
public void testWrapper5() {
    //模糊查询
    // SELECT id,name,age,email,version,deleted,create_time,update_time 
    //FROM user 
    //WHERE deleted=0 AND id IN 
    //(select id from user where id<5)
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    //id 在子查询中查出来
    wrapper.inSql("id","select id from user where id<5");
    List<Object> objects = userMapper.selectObjs(wrapper);
    objects.forEach(System.out::println);
}

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
@Test
public void testWrapper6() {
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    //通过id进行降序排序
    wrapper.orderByDesc("id");
    List<User> userList = userMapper.selectList(wrapper);
    userList.forEach(System.out::println);
}

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)

多数据源

使用方法

1.引入dynamic-datasource-spring-boot-starter。

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
  <version>${version}</version>
</dependency>

2.配置数据源。

spring:
  datasource:
    dynamic:
      primary: master #设置默认的数据源或者数据源组,默认值即为master
      strict: false #严格匹配数据源,默认false. true未匹配到指定数据源时抛异常,false使用默认数据源
      datasource:
        master:
          url: jdbc:mysql://xx.xx.xx.xx:3306/dynamic
          username: root
          password: 123456
          driver-class-name: com.mysql.jdbc.Driver # 3.2.0开始支持SPI可省略此配置
        slave_1:
          url: jdbc:mysql://xx.xx.xx.xx:3307/dynamic
          username: root
          password: 123456
          driver-class-name: com.mysql.jdbc.Driver
        slave_2:
          url: ENC(xxxxx) # 内置加密,使用请查看详细文档
          username: ENC(xxxxx)
          password: ENC(xxxxx)
          driver-class-name: com.mysql.jdbc.Driver
       #......省略
       #以上会配置一个默认库master,一个组slave下有两个子库slave_1,slave_2

3.使用 @DS 切换数据源

@DS 可以注解在方法上或类上,同时存在就近原则 方法上注解 优先于 类上注解

@Service
@DS("slave")
public class UserServiceImpl implements UserService {

  @Autowired
  private JdbcTemplate jdbcTemplate;

  public List selectAll() {
    return  jdbcTemplate.queryForList("select * from user");
  }
  
  @Override
  @DS("slave_1")
  public List selectByCondition() {
    return  jdbcTemplate.queryForList("select * from user where age >10");
  }
}
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