我有一些执行UPSERT的代码，也称为Merge。我想清理这段代码，具体地说，我想摆脱异常处理，并为这种简单的操作降低代码的整体冗长性和纯粹的复杂性。要求是插入每个项目，除非它已经存在：
public void batchInsert(IncomingItem[] items) {
try(Session session = sessionFactory.openSession()) {
batchInsert(session, items);
}
catch(PersistenceException e) {
if(e.getCause() instanceof ConstraintViolationException) {
logger.warn("attempting to recover from constraint violation");
DateTimeFormatter dbFormat = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
items = Arrays.stream(items).filter(item -> {
int n = db.queryForObject("select count(*) from rets where source = ? and systemid = ? and updtdate = ?::timestamp",
Integer.class,
item.getSource().name(), item.getSystemID(),
dbFormat.format(item.getUpdtDateObj()));
if(n != 0) {
logger.warn("REMOVED DUPLICATE: " +
item.getSource() + " " + item.getSystemID() + " " + …我有我的实体如下.我的数据模型在下面执行,我无法更改参照迭代.所以我坚持使用复合键.我想为orderId自动生成/使用一些生成器
是的我已在下面阅读. http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#entity-mapping-identifier
我不想管理id生成过程,因为上面建议应用程序生成orderId.
如何使部分id生成器工作..我的选择是什么...将非常感谢专家的一些想法.
@Entity
@Table(name = "Orders", uniqueConstraints = @UniqueConstraint(columnNames = {"partner_ID", "order_ident" }))
public class Order {
private OrderId id;
public Order() {
}
@EmbeddedId
@AttributeOverrides({
@AttributeOverride(name = "partnerId", column = @Column(name = "partner_ID", nullable = false)),
@AttributeOverride(name = "employeeId", column = @Column(name = "employee_ID", nullable = false)),
@AttributeOverride(name = "orderId", column = @Column(name = "order_ID", nullable = false)) })
public OrderId getId() {
return this.id;
}
public void setId(OrderId id) {
this.id = id;
}
} …