我使用JPA MySQL來執行查詢數據庫,但是當我嘗試仍然存在一些實體沒有行被添加到表的EntityManager不保存實體MySQL數據庫表
這裏是persistense.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="avtoparki" transaction-type="RESOURCE_LOCAL">
<description>
Persistence unit for the JPA tutorial of the Hibernate Getting Started Guide
</description>
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>Entities.City</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/world" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="tauren993" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<property name="hibernate.show_sql" value="true" />
<!-- <property name="hibernate.hbm2ddl.auto" value="create" /> -->
</properties>
</persistence-unit>
</persistence>
這裏是實體類:
@Entity
public class City {
@Id
//@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="ID")
int id;
@Column(name="Name")
String name;
@Column(name="CountryCode")
String CountryCode;
@Column(name="District")
String District;
@Column(name="Population")
int Population;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCountryCode() {
return CountryCode;
}
public void setCountryCode(String countryCode) {
CountryCode = countryCode;
}
public String getDistrict() {
return District;
}
public void setDistrict(String district) {
District = district;
}
public int getPopulation() {
return Population;
}
public void setPopulation(int population) {
Population = population;
}
這裏是代碼:
EntityManagerFactory emf = Persistence.createEntityManagerFactory("avtoparki");
EntityManager em = emf.createEntityManager();
City city = new City();
city.setCountryCode("Georgia");
city.setDistrict("AVOIE");
city.setName("Tbilisi");
city.setId(1);
em.persist(city);
em.close();
System.out.println("SAVED");
當我執行沒有錯誤,它只是不將其保存到表(城市表存在和架構是相同的
你有沒有打過電話'他們。在em.close()之前使用flush()'? – micha
看起來像手動實體管理器創建,所以我希望手動啓動和提交事務。 – Gimby