1. @Transient
@Transient indicates that the property is not a mapping to a field in a database table, and the ORM framework ignores the property;
If a property is not a field mapping for a database table, it must be marked as @transient, otherwise the ORM framework defaults to its annotation as @basic;
Indicates that the field is not in the database table
@Transient
public int getage () {
return;
}
Jackson Related:
2. @JsonIgnoreProperties
This annotation is a class annotation that, when JSON is serialized, ignores some properties in the Java Bean, and both serialization and deserialization are affected.
3. @JsonIgnore
This annotation is used on properties or methods (preferably on attributes), as in the @jsonignoreproperties above.
4. @JsonFormat
This annotation is used for attributes or methods (preferably on attributes), and it is convenient to convert the date type directly into the pattern we want, such as @jsonformat (pattern = "Yyyy-mm-dd hh-mm-ss")
5. @JsonSerialize
This annotation is used on attributes or Getter methods to embed our custom code when serializing, such as when serializing a double with a two-bit decimal point behind it.
6. @JsonDeserialize
This annotation is used on attributes or setter methods, and can be used to embed our custom code when deserializing, similar to the above @jsonserialize
* The JPA namedqueries can be used as follows:1: Use @namedquery on the entity class, as shown in the following example:@NamedQuery (name = "Usermodel.findbyage", query = "Select O from Usermodel o where o.age >=? 1")
Note: Use the following annotations when defining multiple
@NamedQueries (value = {
@NamedQuery (name = User.query_find_by_login,
query = "Select u from User u where u." + User.prop_login
+ "=: username"),
@NamedQuery (name = "Getusernamepasswordtoken",
query = "Select New Com.aceona.weibo.vo.TokenBO (U.username,u.password) from User u where u." + User.prop_login
+ "=: Username")}) 2: Define a method of the same name in the Repository interface of the DAO that you implement, with the following example:Public list<usermodel> Findbyage (int.);3: Then it can be used, and spring will first find out if there is a namedquery with the same name, and if so, it will not be parsed according to the method defined by the interface.
* Using @querysuch a query can be declared in an inherited Jparepository interface method that can be used on a custom query method to specify the query statement that the method executes, such as:@Query ("Select O from Usermodel o where o.uuid=?1")Public list<usermodel> findbyuuidorage (int uuid);
Note:1: The number of parameters of the method must be the same as the number of parameters required in @query2: If it is like, the following parameters need to be preceded or followed by "%", for example:@Query ("Select O from Usermodel o where o.name like? 1%")Public list<usermodel> findbyuuidorage (String name); @Query ("Select O from Usermodel o where o.name like%?1")Public list<usermodel> findbyuuidorage (String name); @Query ("Select O from Usermodel o where o.name like%?1%")Public list<usermodel> findbyuuidorage (String name); of course, it is possible to pass the parameter value when you can not add '% ', of course, it is not wrong to add n You can also use @query to specify local queries, as long as you set Nativequery to True, such as:@Query (value= "select * from Tbl_user where name is like%?1", Nativequery=true)Public list<usermodel> findbyuuidorage (String name);
Note: The current version of the local query does not support page flipping and dynamic sorting Using named parameters, you can use @param, for example:@Query (value= "Select O from Usermodel o where o.name like%:nn")Public list<usermodel> Findbyuuidorage (@Param ("nn") String name);also support for updating the query statement of the class, add @modifying can, for example:@Modifying@Query (value= "Update Usermodel o set o.name=:newname where o.name like%:nn")public int Findbyuuidorage (@Param ("nn") string name, @Param ("NewName") string newName);
Note:1: The return value of the method should be int, indicating the number of rows affected by the UPDATE statement2: A transaction must be added at the place of invocation, no transaction can be performed normally
Spring Data JPA Common annotations @Query, @NamedQuery
