15.1 枚举类型 枚举定义的符号是常量值. C#编译器编译时,会用数值替换符号,不再引用定义了符号的枚举类型.可能会出现一些版本问题. Enum.IsDefined(Type enumType, object value)方法被经常用于参数校验: public void SetColor(ConsoleColor c) { if (!Enum.IsDefined(typeof(ConsoleColor), c)) { throw new ArgumentOutOfRangeException(…
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…
一.简介 1. 2. 3. 4. to override this default mapping. The JPA specification has a convenient shortcut annotation for this purpose, @Lob @Entity public class Item { @Lob protected byte[] image; @Lob protected String description; // ... } This maps the by…
Each @AttributeOverride for a component property is “complete”: any JPA or Hibernate annotation on the overridden property is ignored. This means the @Column annotations on the Address class are ignored—all BILLING_* columns are NULL able!(Bean Valid…
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…
