Question

Eclipselink动态持久性允许多个主键： DynamicTypeBuilder.setPrimaryKeyFields(String primarykeysField...)

但是如何通过 EntityManager.find( Entity Class , Object primaryKey)方法找到实体对象（实例）以在复合主键的情况下查找实体（多个主键）（因为没有IdClass或EmbeddedId）动态持久性。

EclipseLink在find（）操作中获取pk列表但是如果在示例中定义了复合pk键 -

Entity = Person
Fields = username,emailId,firstName,lastName
Composite PK = username,emailId

Class<?> clazz = new DynamicClassLoader(Thread.currentThread().getContextClassLoader()).createDynamicClass("Person");
DynamicTypeBuilder builder = new DynamicTypeBuilder(clazz, null, "Person");
DynamicType dynamicType = builder.getType();
builder.setPrimaryKeyFields(["username","emailId"]);
builder.addDirectMapping("username",String.class,"username");
builder.addDirectMapping("emailId",String.class,"emailId");
builder.addDirectMapping("firstName",String.class,"firstName");
builder.addDirectMapping("lastName",String.class,"lastName");

List list = new ArrayList();
list.add(${username}); //Run time value
list.add(${emailId}); //Run time value

然后 EnitityManager.find(dynamicType.getJavaClass(),list) 将采取这些论点，我是对的吗？如果我假设正确，则EnitityManager.find()操作将如何知道List 1st参数是username或emailId pk值（表示复合pk字段值的序列）而不是Map ({username:${username},emailId:${emailId}})或其他DataStucture。

Answer 1

您应该可以使用带有find（）操作的List。

JPA EclipseLink DynamicPersistence中的复合主键

1 个答案: