У меня небольшой «сложный» вопрос.
Я использую Hibernate / JPA для транзакций с БД.
Я не администратор баз данных, и клиент использует мое приложение, веб-сервис RESTful. Моя проблема в том, что БД изменяется (не очень часто, но все равно меняется). Кроме того, клиент не всегда учитывает ввод для моего приложения (длина, тип и т. Д.). Когда это происходит, Hibernate создает исключение. Исключение трудно перевести и прочитать из журнала, потому что оно содержит вложенные исключения и состоит из большого количества текста: как я уже сказал, очень трудно понять.
Я хочу знать, возможно ли обрабатывать исключения на уровне сущности, возможно, выбрасывая индивидуальное исключение.
Благодарю за терпение и помощь заранее.
EDIT:
В общем-то, мне удалось сделать то, что я хотел, но я не был уверен, что все сделано правильно .
App.java
package com.mc;
import org.hibernate.Session;
import com.mc.stock.Stock;
import com.mc.util.HibernateUtil;
import javax.persistence.EntityManager;
public class App {
public static void main(String[] args) {
Set<ConstraintViolation<Stock>> violations;
validator = Validation.buildDefaultValidatorFactory().getValidator();
Scanner scan = new Scanner(System.in);
EntityManager em = null;
System.out.println("Hibernate one to many (Annotation)");
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
Stock stock = new Stock();
String nextLine = scan.nextLine();
stock.setStockCode(nextLine.toString());
nextLine = scan.nextLine();
stock.setStockName(nextLine.toString());
violations = validator.validate(stock);
if (violations.size() > 0) {
StringBuilder excepcion = new StringBuilder();
for (ConstraintViolation<Stock> violation : violations) {
excepcion.append(violation.getMessageTemplate());
excepcion.append("\n");
}
System.out.println(excepcion.toString());
}
session.save(stock);
session.getTransaction().commit();
}
}
FieldMatch.java
package com.mc.constraints;
import com.mc.constraints.impl.FieldMatchValidator;
import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.ElementType.TYPE;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Target;
@Target({TYPE, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = FieldMatchValidator.class)
@Documented
public @interface FieldMatch {
String message() default "{constraints.fieldmatch}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String first();
String second();
@Target({TYPE, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Documented
@interface List {
FieldMatch[] value();
}
}
FieldMatchValidator.java
package com.mc.constraints.impl;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import com.mc.constraints.FieldMatch;
import org.apache.commons.beanutils.BeanUtils;
public class FieldMatchValidator implements ConstraintValidator<FieldMatch, Object> {
private String firstFieldName;
private String secondFieldName;
@Override
public void initialize(final FieldMatch constraintAnnotation) {
firstFieldName = constraintAnnotation.first();
secondFieldName = constraintAnnotation.second();
}
@Override
public boolean isValid(final Object value, final ConstraintValidatorContext context) {
try {
final Object firstObj = BeanUtils.getProperty(value, firstFieldName);
final Object secondObj = BeanUtils.getProperty(value, secondFieldName);
return firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
} catch (final Exception ignore) {
// ignore
}
return true;
}
}
Stock.java
package com.mc.stock;
import com.mc.constraints.FieldMatch;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;
import org.hibernate.annotations.Cascade;
import org.hibernate.annotations.CascadeType;
import org.hibernate.validator.constraints.Length;
@Entity
@Table(name = "STOCK")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Stock.findAll", query = "SELECT s FROM Stock s"),
@NamedQuery(name = "Stock.findByStockId", query = "SELECT s FROM Stock s WHERE s.stockId = :stockId"),
@NamedQuery(name = "Stock.findByStockCode", query = "SELECT s FROM Stock s WHERE s.stockCode = :stockCode"),
@NamedQuery(name = "Stock.findByStockName", query = "SELECT s FROM Stock s WHERE s.stockName = :stockName")})
@FieldMatch.List({
@FieldMatch(first = "stockCode", second = "stockName", message = "Code and Stock must have same value")
})
public class Stock implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seq_stock_id")
@SequenceGenerator(name = "seq_stock_id", sequenceName = "seq_stock_id", initialValue = 1, allocationSize = 1)
@Basic(optional = false)
@Column(name = "STOCK_ID", unique = true, nullable = false)
private Integer stockId;
@Column(name = "STOCK_CODE")
private String stockCode;
@Length(min = 1, max = 20, message = "{wrong stock name length}")
@Column(name = "STOCK_NAME")
private String stockName;
public Stock() {
}
public Stock(Integer stockId) {
this.stockId = stockId;
}
public Integer getStockId() {
return stockId;
}
public void setStockId(Integer stockId) {
this.stockId = stockId;
}
public String getStockCode() {
return stockCode;
}
public void setStockCode(String stockCode) {
this.stockCode = stockCode;
}
public String getStockName() {
return stockName;
}
public void setStockName(String stockName) {
this.stockName = stockName;
}
@Override
public int hashCode() {
int hash = 0;
hash += (stockId != null ? stockId.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Stock)) {
return false;
}
Stock other = (Stock) object;
if ((this.stockId == null && other.stockId != null) || (this.stockId != null && !this.stockId.equals(other.stockId))) {
return false;
}
return true;
}
@Override
public String toString() {
return "com.mc.stock.Stock[ stockId=" + stockId + " ]";
}
}
HibernateUtil.java
package com.mc.util;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
public static void shutdown() {
// Close caches and connection pools
getSessionFactory().close();
}
}
Структура БД Oracle
CREATE TABLE stock
(
STOCK_ID NUMBER(5) NOT NULL ,
STOCK_CODE VARCHAR2(10) NULL ,
STOCK_NAME VARCHAR2(20) NULL
);
ALTER TABLE stock
add CONSTRAINT PK_STOCK_ID PRIMARY KEY (STOCK_ID);
create sequence seq_stock_id
start with 1
increment by 1
nomaxvalue;