Generic Example usage of mybatis' generic mapper

General Example use of mybatis general mapper , of course, there are also general Example uses that do not correspond to general mapper

If you want to be lazy and not write a lot of mapper.xml files in mybatis, you want to use the generic Mapper class to reduce the workload.

    First, I'm using a Maven project, so import Mapper's Maven dependencies

 

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1. <dependency>  
2.   <groupId>tk.mybatis</groupId>  
3.   <artifactId>mapper</artifactId>  
4.   <version>3.2.0</version>  
5. </dependency>    

    At the same time, there is a necessary dependency: the project depends on JPA annotations, and Maven dependencies need to be added:

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1. <dependency>  
2.   <groupId>javax.persistence</groupId>  
3.   <artifactId>persistence-api</artifactId>  
4.   <version>1.0</version>  
5. </dependency>  

    Next, configure Mapper in the configuration file applicationContext.xml

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1. <beanclass="tk.mybatis.spring.mapper.MapperScannerConfigurer">   
2.     <propertyname="basePackage"value="com.isscas.ucqcs.common.dao"/>    
3.     <propertyname="properties">   
4.         <value>  
5.             mappers = tk .mybatis.mapper.common.Mapper //This is the Mapper interface configuration. When the interface is configured by default, it is not necessary to write  
6.         </value>  
7.     </property>  
8. </bean>  

    Just change the configuration org of MyBatis to tk directly

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1. <beanclass="org.mybatis.spring.mapper.MapperScannerConfigurer">   

    At this point, the configuration of Mapper has been completed.

 

    As long as you inherit the Mapper<T> interface on your own Mapper interface, you can call all the methods in the general Mapper class.

    另外要注意的是：该Mapper类对实体类有自己的解析方式  ：  表名和字段名会默认使用类名,驼峰转下划线（即UserNamed对应表名/字段名user_name），使用@Column(name = "真实名称")可以指定表名/字段名。

    另，需要@Id标记主键字段，对不需要的字段，可用@Tranisent忽略

    Mapper接口中包含单表的增删改查分页功能。

    下面给出一个查询实例：

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1. CountryMapper mapper = sqlSession.getMapper(CountryMapper.class);  
2. //查询全部  
3. List<Country> countryList = mapper.select(new Country());  
4. //总数  
5.   
6. //通用Example查询  
7. Example example = new Example(Country.class);  
8. example.createCriteria().andGreaterThan("id", 100);//这里给出的条件查询为id>100  
9. countryList = mapper.selectByExample(example);  

项目示例：

@Override

public String getSimpleOfTree(String customerKey) {

// TODO Auto-generated method stub

Example example = new Example(TbCusFirmrelgroup.class);///Note that the attributes in the class are used, not the attributes in the database

example.setOrderByClause(" groupKey asc");// Note that the properties in the class are used, not the properties in the database

example.createCriteria().andEqualTo("customerKey",BigDecimal.valueOf(Long.valueOf(customerKey)));

List<TbCusFirmrelgroup> cusPowerGroupList =  tbCusFirmrelgroupMapper.selectByExample(example);

return null;

}