lickysee's recent timeline updates lickysee's recent timeline updates | lickyseeV2EX member #453844, joined on 2019-11-18 15:00:05 +08:00 |
| 迫于工作，众筹一个 intellij idea 的可行性 无要点 lickysee Jan 10, 2020 Lastly replied by xiaobai332 | 32 |
| ios 企业签名服务用不了了？ 问与答 lickysee Nov 19, 2019 |
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Jun 16, 2020 Replied to a topic by piapia123 程序员 如何缓解理财亏损带来的心理不适 |
大不了从头再来
Jun 11, 2020 Replied to a topic by yumc Java 关于 spring data jpa 的一些业务问题 |
大致上的思路就是将判断如果是空就不进行查询这种重复的代码提取出来，返回一个 Specification，然后结合官方给出来的例子，进行条件的拼接。
参照官方文档 Example 98. Combined Specifications
参照官方文档 Example 98. Combined Specifications
Jun 11, 2020 Replied to a topic by yumc Java 关于 spring data jpa 的一些业务问题 |
提供一个自己的思路，代码仅供参考，希望对你有帮助。
```
public class SpecificationUtil {
public static <T> Specification<T> stringLike(
final String field,
final String param
) {
return skipNullAndBlank(
param,
(builder, root) -> builder.like(root.get(field), "%" + param + "%")
);
}
private static <T> Specification<T> skipNullAndBlank(
String p,
BiFunction<CriteriaBuilder, Root<T>, Predicate> f
) {
return ((Specification<T>) (root, query, builder) -> {
if (Strings.isBlank(p)) {
return query.getGroupRestriction();
} else {
return f.apply(builder, root);
}
});
}
}
```
```
public class SpecificationUtil {
public static <T> Specification<T> stringLike(
final String field,
final String param
) {
return skipNullAndBlank(
param,
(builder, root) -> builder.like(root.get(field), "%" + param + "%")
);
}
private static <T> Specification<T> skipNullAndBlank(
String p,
BiFunction<CriteriaBuilder, Root<T>, Predicate> f
) {
return ((Specification<T>) (root, query, builder) -> {
if (Strings.isBlank(p)) {
return query.getGroupRestriction();
} else {
return f.apply(builder, root);
}
});
}
}
```
Jun 11, 2020 Replied to a topic by yumc Java 关于 spring data jpa 的一些业务问题 |
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