tkmapper教程_tkmapper

<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-spring-boot-starter</artifactId>
  <version>版本号</version>
</dependency>

@tk.mybatis.spring.annotation.MapperScan(basePackages = "扫描包")
@SpringBootApplication
public class SampleMapperApplication implements CommandLineRunner { 

mapper:
  mappers:
    - tk.mybatis.mapper.common.Mapper
    - tk.mybatis.mapper.common.Mapper2
  notEmpty: true

normal,                     //原值
camelhump,                  //驼峰转下划线
uppercase,                  //转换为大写
lowercase,                  //转换为小写
camelhumpAndUppercase,      //驼峰转下划线大写形式
camelhumpAndLowercase,      //驼峰转下划线小写形式
@NameStyle(Style.camelhumpAndUppercase)
public class Country   //会将形如 userName 的字段转换为表中的 USER_NAME 字段

@Table(name = "sys_user")  //将 User 实体映射到 sys_user 表
public class User

@Column(name = "user_name")  //映射 name 到 user_name
private String name;

// mysql关键字 order 映射
@Column(name = "`order`")
private String order;

@Transient
private String otherThings; //非数据库表中字段

//联合主键
@Id
private Integer userId;
@Id
private Integer roleId;

@Id
@KeySql(useGeneratedKeys = true)
private Long id;

//通用 Mapper 提供了下面这些参数：
mappers
IDENTITY
ORDER(别名: order, before)
catalog
schema
notEmpty
style
enableMethodAnnotation
useSimpleType
usePrimitiveType
simpleTypes
enumAsSimpleType
wrapKeyword
checkExampleEntityClass
safeDelete
safeUpdate
useJavaType

//取回主键的方式，列表数据库名字后面对应的 SQL 是插入后取 id 的 SQL 语句。
DB2: VALUES IDENTITY_VAL_LOCAL()
MYSQL: SELECT LAST_INSERT_ID()
SQLSERVER: SELECT SCOPE_IDENTITY()
CLOUDSCAPE: VALUES IDENTITY_VAL_LOCAL()
DERBY: VALUES IDENTITY_VAL_LOCAL()
HSQLDB: CALL IDENTITY()
SYBASE: SELECT @@IDENTITY
DB2_MF: SELECT IDENTITY_VAL_LOCAL() FROM SYSIBM.SYSDUMMY1
INFORMIX: select dbinfo('sqlca.sqlerrd1') from systables where tabid=1

IDENTITY=MYSQL   //配置

//配置方式：
notEmpty=true

normal：原值
camelhump：驼峰转下划线
uppercase：转换为大写
lowercase：转换为小写
camelhumpAndUppercase：驼峰转下划线大写形式
camelhumpAndLowercase：驼峰转下划线小写形式

wrapKeyword=`{ 
   0}`   //mysql配置
//使用该配置后，类似 private String order 就不需要通过 @Column 来指定别名。

默认 false 用于校验通用 Example 构造参数 entityClass 是否和当前调用的 Mapper<EntityClass> 类型一致。
假设存在下面代码：
Example example = new Example(City.class);
example.xxx...;//设置条件的方法
countryMapper.selectByExample(example);
注意，这里使用 City 创建的 Example，本该使用 cityMapper 来调用，但是这里使用了 countryMapper
配置该字段为 true 后就会对不匹配的情况进行校验！
 checkExampleEntityClass=true

Caused by: tk.mybatis.mapper.MapperException: 通用 Mapper 安全检查: 当前操作的方法没有指定查询条件，不允许执行该操作!

Example example = new Example(Country.class);
example.setForUpdate(true);
example.createCriteria().andGreaterThan("id", 100).andLessThan("id",151);
example.or().andLessThan("id", 41);
List<Country> countries = mapper.selectByExample(example);
//日志
DEBUG [main] - ==>  Preparing: SELECT id,countryname,countrycode FROM country WHERE ( id > ? and id < ? ) or ( id < ? ) ORDER BY id desc FOR UPDATE 
DEBUG [main] - ==> Parameters: 100(Integer), 151(Integer), 41(Integer)

Example example = new Example(Country.class);
Example.Criteria criteria = example.createCriteria();
if(query.getCountryname() != null){ 

criteria.andLike("countryname", query.getCountryname() + "%");
}
if(query.getId() != null){ 

criteria.andGreaterThan("id", query.getId());
}
List<Country> countries = mapper.selectByExample(example);
//日志：
DEBUG [main] - ==>  Preparing: SELECT id,countryname,countrycode FROM country WHERE ( countryname like ? ) ORDER BY id desc 
DEBUG [main] - ==> Parameters: China%(String)

Example example = new Example(Country.class);
example.orderBy("id").desc().orderBy("countryname").orderBy("countrycode").asc();
List<Country> countries = mapper.selectByExample(example);
//日志：
DEBUG [main] - ==>  Preparing: SELECT id,countryname,countrycode FROM country order by id DESC,countryname,countrycode ASC 
DEBUG [main] - ==> Parameters: 

CountryExample example = new CountryExample();
//设置 distinct
example.setDistinct(true);
example.createCriteria().andCountrynameLike("A%");
example.or().andIdGreaterThan(100);
List<Country> countries = mapper.selectByExample(example);
//日志：
DEBUG [main] - ==>  Preparing: SELECT distinct id,countryname,countrycode FROM country WHERE ( countryname like ? ) or ( Id > ? ) ORDER BY id desc 
DEBUG [main] - ==> Parameters: A%(String), 100(Integer)

Example example = new Example(Country.class);
example.selectProperties("id", "countryname");
List<Country> countries = mapper.selectByExample(example);
//日志：
DEBUG [main] - ==>  Preparing: SELECT id , countryname FROM country ORDER BY id desc 
DEBUG [main] - ==> Parameters: 

Example example = Example.builder(Country.class)
.select("countryname")
.where(Sqls.custom().andGreaterThan("id", 100))
.orderByAsc("countrycode")
.forUpdate()
.build();
List<Country> countries = mapper.selectByExample(example);
//日志：
DEBUG [main] - ==>  Preparing: SELECT countryname FROM country WHERE ( id > ? ) order by countrycode Asc FOR UPDATE 
DEBUG [main] - ==> Parameters: 100(Integer)

List<Country> selectByWeekendSql = mapper.selectByExample(new Example.Builder(Country.class)
.where(WeekendSqls.<Country>custom().andLike(Country::getCountryname, "%a%")
.andGreaterThan(Country::getCountrycode, "123"))
.build());
//日志：
DEBUG [main] - ==>  Preparing: SELECT id,countryname,countrycode FROM country WHERE ( countryname like ? and countrycode > ? ) 
DEBUG [main] - ==> Parameters: %a%(String), 123(String)

//只有接口时，加下面的注解即可
@CacheNamespace
public interface CountryCacheMapper extends Mapper<Country> { 
}

//1.在 XML 中定义缓存：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="tk.mybatis.mapper.cache.CountryCacheRefMapper">
<cache/>  //这里配置
<select id="selectById" resultType="tk.mybatis.mapper.base.Country">
select * from country where id = #{ 
id}
</select>
</mapper>
//2.在接口中配置注解引用：接口类名或xml的namespace
@CacheNamespaceRef(CountryCacheRefMapper.class)
//或者 @CacheNamespaceRef(name = "tk.mybatis.mapper.cache.CountryCacheRefMapper")
public interface CountryCacheRefMapper extends Mapper<Country> { 

// 定义在 XML 中的方法
Country selectById(Integer id);
}
//@CacheNamespaceRef 指定的是缓存的 namespace，就是 XML 中 <mapper> 中的 namespace 属性。