java 查询@ElementCollection JPA
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Query @ElementCollection JPA
提问by prayagupd
I have an EntityTransactionas following :
我有EntityTransaction以下内容：
@Entity
class Transaction extends AbstractEntity<Long>{
private static final long serialVersionUID = 7222139865127600245L;
//other attributes
@ElementCollection(fetch = FetchType.EAGER, targetClass = java.lang.String.class)
@CollectionTable(name = "transaction_properties", joinColumns = @JoinColumn(name = "p_id"))
@MapKeyColumn(name = "propertyKey")
@Column(name = "propertyValue")
private Map<String, String> properties;
//getters and setters
}
So, my Database Tablefor transaction_propertiesis
所以，我的数据库Table为transaction_properties是
mysql> desc transaction_properties;
+---------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+-------+
| p_id | bigint(20) | NO | PRI | | |
| propertyValue | varchar(255) | YES | | NULL | |
| propertyKey | varchar(255) | NO | PRI | | |
+---------------+--------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
Now, I want to search entity Transactionwith key and value.
现在，我想Transaction用键和值搜索实体。
Path<Map<String, String>> propertiesPath = root.get("properties");
Path<String> propertyKeyPath = propertiesPath.<String> get("propertyKey"); //where m getting error
Path<String> propertyValuePath = propertyKeyPath.<String> get("propertyValue");
p = cb.and(p, cb.and(cb.like(propertyKeyPath, "%" + searchTrxnKey + "%"), cb.like(propertyValuePath, "%" + searchTrxnValue + "%")));
But am getting error for Path<String> propertyKeyPath = propertiesPath.<String> get("propertyKey");as following :
但我收到Path<String> propertyKeyPath = propertiesPath.<String> get("propertyKey");如下错误：
[...] threw an unexpected exception: org.springframework.dao.InvalidDataAccessApiUsageException: Illegal attempt to dereference path source [null]; nested exception is java.lang.IllegalArgumentException: Illegal attempt to dereference path source [null]
One of the reference I went through was : Spring Data JPA Tutorial Part Four: JPA Criteria Queriesbut no luck for me.
我阅读的参考资料之一是：Spring Data JPA 教程第四部分：JPA Criteria Queries但对我来说没有运气。
回答by prayagupd
The solution is .join("properties")than .get("properties").
解决方案是.join("properties")比.get("properties")。
Path<Map<String, String>> propertiesPath = root.join("properties");
predicate = (predicate != null) ? criteriaBuilder.and(predicate, criteriaBuilder.and(propertiesPath.in(searchTrxnKey), propertiesPath.in(searchTrxnValue)))
: criteriaBuilder.and(propertiesPath.in(searchTrxnKey), propertiesPath.in(searchTrxnValue));
More at JPA Criteria API - How to add JOIN clause (as general sentence as possible)
