你可以把你的Specification
s 定义到辅助类中:
public class DelegationSpecificationsHelper {
public static Specification<Domain> notificationContactSpec(String contact) {
return (root, query, cb) -> cb.equal(root.join("notification").get("contact"), contact);
}
public static Specification<Domain> idSpec(SearchCriteria searchCriteria) {
switch (criteria.getOperation()) {
case ":":
if (root.get(criteria.getKey()).getJavaType() == String.class) {
return builder.like(
root.<String>get(criteria.getKey()),
"%" + criteria.getValue() + "%");
} else {
return builder.equal(root.get(criteria.getKey()),
criteria.getValue());
}
case "=":
return builder.equal(root.get(criteria.getKey()),
criteria.getValue());
default:
return null;
}
}
}
然后你可以像这样使用它:
Specifications<Domain> specifications = Specifications.where(DelegationSpecificationsHelper.idSpec(new SearchCriteria("id", "=", domainId))
.and(DelegationSpecificationsHelper.notificationContactSpec("someSearchString"));
静态导入和一些重构之后:
SearchCriteria idCriteria = new SearchCriteria("id", "=", domainId)
Specifications<Domain> specifications =
Specifications.where(idSpec(idCriteria)
.and(notificationContactSpec("someSearchString"));
当然,您应该从这里删除硬编码值:cb.equal(root.join("notification").get("contact"), contact);
并使用一些 DTO 对象或生成的 JPA 元模型代替。
添加元模型后,它可能看起来像这样:
public static Specification<Domain> notificationContactSpec(String contactValue) {
return (root, query, cb) -> cb.equal(root.join(Domain_.notification).get(Notification_.contact), contactValue);
}
有关元模型生成的更多信息:https://docs.jboss.org/hibernate/orm/5.0/topical/html/metamodelgen/MetamodelGenerator.html https://docs.jboss.org/hibernate/orm/5.0/topical/html/metamodelgen/MetamodelGenerator.html