一.简介 1.You now have three methods for distinguishing references:  Objects are identical if they occupy the same memory location in the JVM . This can be checked with the a == b operator. This concept is known as object identity. Objects are equal i…

一.自定义映射的表名 1. @Entity @Table(name = "USERS") public class User implements Serializable { // ... } 2.用定界符 //@Table(name = "`USER`")的标准 @Table(name = "`USER`") //JPA的标准 @Table(name = "\"USER\"") 若全部SQL都加定界符,…

一.结构 二.配置文件约定 The JPA provider automatically picks up this descriptor if you place it in a META-INF /orm.xml file on the classpath of the persistence unit. If you prefer to use a different name or several files, you’ll have to change the configuratio…

一.结构 二.model层 1. package org.jpwh.model.helloworld; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; /* Every persistent entity class must have at least th…

一.结构 For example, you can map a class hierarchy to a single table, but, for a particular subclass, switch to a separate table with a foreign key–mapping strategy, just as with table-per-subclass. 二.代码 1. package org.jpwh.model.inheritance.mixed; impo…

一.代码 1. package org.jpwh.model.inheritance.tableperclass; import org.jpwh.model.Constants; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Inheritance; import javax.persi…

一.结构 二.代码 1. package org.jpwh.model.inheritance.mappedsuperclass; import javax.persistence.MappedSuperclass; import javax.validation.constraints.NotNull; @MappedSuperclass public abstract class BillingDetails { @NotNull protected String owner; // ...…

There are four different strategies for representing an inheritance hierarchy: Use one table per concrete class and default runtime polymorphic behavior. Use one table per concrete class but discard polymorphism and inheritance relationships comple…

一.结构 二.Hibernate支持的UserTypes接口  UserType —You can transform values by interacting with the plain JDBC PreparedStatement (when storing data) and ResultSet (when loading data).By implementing this interface, you can also control how Hibernate caches a…

一.结构 二.代码 1. package org.jpwh.model.advanced; import java.io.Serializable; import java.math.BigDecimal; import java.util.Currency; /* This value-typed class should be <code>java.io.Serializable</code>: When Hibernate stores entity instance dat…