1. Annotation
(1) @Data : Use @Data on beans to omit get and set methods
(2) @Entity : Represents an entity class
(3) @Table : Use @Table on the bean class (name="tableName") name is the database table name
(4) @Id @GeneratedValue : used on the primary key field to represent the primary key
(5) @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone="GMT+8") The time field sets the time format
(6) @Temporal: Attribute of Date type, which may be stored in the database as 'yyyy-MM-dd hh:MM:ss' To get the year, month, and day when querying, marking this attribute with @Temporal(TemporalType.DATE) will Get a date in the format 'yyyy-MM-dd', @Temporal(TemporalType.TIME) will get a date in the format 'HH:MM:SS', @Temporal(TemporalType.TIMESTAMP) will get a date in the format ' yyyy- Date in MM-dd hh:MM:ss ' format
(7) @Column(name="zd",nullable=false,length=512): Specify the field " zd 's length 512 ", and the value cannot be null
@Column(name="zd", precision=12, scale=2) is of type double with 12 digits of precision and 2 digits of decimal point .
@Column(name="zd",columnDefinition="clob not null") Customize the SQL statement for generating CLOB type fields, equivalent to contact_name clob (200) not null
@Column(updatable=false) When inserting data using " UPDATE " script, the value of this field does not need to be updated
@Column( insertable = false ) Whether the value of this field needs to be inserted when inserting data using the " INSERT " script.
(7-1) The unique attribute indicates whether the field is a unique identifier, and the default value is false . If there is a field in the table that needs to be uniquely identified, you can use either that tag or @UniqueConstraint in the @Table tag .
( 7-2 ) The nullableproperty indicates whether the field can be anullvalue, and the default istrue.
( 7-3 ) The insertableattribute indicateswhether the value of the field needs to be inserted when inserting dataINSERT
( 7-4 ) The updatableattribute indicates whether the value of this field needs to be updated when data is inserted using the "UPDATE" script. The insertableandupdatableattributes are generally used for read-only attributes, such as primary keys and foreign keys. The values for these fields are usually automatically generated.
( 7-5 ) The columnDefinitionattribute indicates that when creating a table, theSQLstatement created by this field is generally used togenerate table definitionsEntity
( 7-6 ) The tableattribute represents the fields in the table of the specified table when mapping multiple tables. The default is the table name of the main table.
(7-7) length属性表示字段的长度，当字段的类型为varchar时，该属性才有效，默认为255个字符。
(7-8) precision属性和scale属性表示精度，当字段类型为double时，precision表示数值的总长度，scale表示小数点所占的位数。
(8) @Query(value="hql") hql 中 表明是对应的实体类名（即用实体类名代替表名 如 select o from 实体类名 o where zd =？1 (两处的o要一致)） 2.索引值从1开始，查询中'?x'的个数要和方法的参数个数一致，且顺序也要一致
@Query(value="select count(1) from 表名",nativeQuery=true) ：nativeQuery=true 表示hql中使用的是数据库表名查询
(9) @Param : 如果在@Query 使用:cs的形式则在方法的需要用@Param 接收参数，如@Query(value=" SELECT b FROM OutLink b where URL like %:url%") 则接口的方法要这样写：void findByUrl(@Param(value = "url") String url）；
(10)@Modifying 在更新或删除时 在@Query 上加上该注解
(11) @Transactional 事物管理 在更新或删除时 必须在servide层的实现类相应的方法上加上该注解，否则会报错
(12)@RestController：相当于@ResponseBody ＋ @Controller ， 如果只是使用@RestController注解Controller，则Controller中的方法无法返回jsp页面，或者html，配置的视图解析器 InternalResourceViewResolver不起作用，返回的内容就是Return 里的内容。如果需要返回到指定页面，则需要用 @Controller配合视图解析器InternalResourceViewResolver才行，如果需要返回JSON，XML或自定义mediaType内容到页面，则需要在对应的方法上加上@ResponseBody注解。 @RestController注解，相当于@Controller+@ResponseBody两个注解的结合，返回json数据不需要在方法前面加@ResponseBody注解了，但使用@RestController这个注解，就不能返回jsp,html页面，视图解析器无法解析jsp,html页面 这是springMvc的知识
比较详细的lianjie：http://www.360doc.com/content/15/0924/12/834950_501215239.shtml