根据我读过的文档here它说:
Hibernate save 方法立即返回生成的 id,这是可能的,因为一旦调用 save 方法,主对象就会被保存。
但在下面的示例中,我触发了 save 方法,然后使线程保持 sleep 状态 1 分钟。 在这个时间空间内,当我检查数据库时,person_o 表中没有显示任何数据。为什么保存后不立即显示年龄和名称值。尽管它是在 sleep 结束后执行提交后出现的。
addperson.java:
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class addperson {
public static void main(String as[])
{
//Activate Hibernate Software
Configuration cfg=new Configuration();
//make hibernate software locating and reading cfg file
cfg=cfg.configure("/hibernate.cfg.xml");
//create SessionFactory obj
SessionFactory factory=cfg.buildSessionFactory();
//create HB session obj
Session session=factory.openSession();
Transaction tx = session.beginTransaction();
try {
// Create a person
person person = new person();
person.setName("Luna");
person.setAge(33);
Integer key = (Integer) session.save(person);
System.out.println("Primary Key : " + key);
person.setId(key);
System.out.println("---going for sleep---");
Thread.sleep(60000);
// Create the address for the person
personaddress address = new personaddress();
address.setAddressLine1("Lunaris");
address.setCity("Twinkle");
address.setState("MA");
address.setZipCode(10308);
address.setPerson(person);
person.setAddress(address);
key = (Integer) session.save(address);
System.out.println("Primary Key again : " + key);
tx.commit();
} catch (Exception e) {
e.printStackTrace();
tx.rollback();
} finally {
session.close();
}
}
}
person.java
import java.io.Serializable;
public class person implements Serializable {
private static final long serialVersionUID = -9127358545321739524L;
private int id;
private String name;
private int age;
private personaddress address;
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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public personaddress getAddress() {
return address;
}
public void setAddress(personaddress address) {
this.address = address;
}
}
personaddress.java
import java.io.Serializable;
public class personaddress implements Serializable {
private static final long serialVersionUID = -9127358545321739523L;
private int id;
private String addressLine1;
private String city;
private String state;
private int zipCode;
private person person;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getAddressLine1() {
return addressLine1;
}
public void setAddressLine1(String addressLine1) {
this.addressLine1 = addressLine1;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public int getZipCode() {
return zipCode;
}
public void setZipCode(int zipCode) {
this.zipCode = zipCode;
}
public person getPerson() {
return person;
}
public void setPerson(person person) {
this.person = person;
}
}
hibernate.cfg.xml
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>
<property name="hibernate.connection.username">system</property>
<property name="hibernate.connection.password">oracle123</property>
<property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
<property name="hibernate.hbm2ddl.auto">create</property>
<property name="show_sql">true</property>
<mapping resource="person.hbm.xml"/> <mapping resource="personaddress.hbm.xml"/>
</session-factory>
</hibernate-configuration>
person.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping >
<class name="person" table="persons_o">
<id name="id" column="P_ID" type="integer">
<generator class="increment" />
</id>
<property name="name" column="NAME" update="false"
type="string" />
<property name="age" column="AGE" type="integer" />
<one-to-one name="address" cascade="all"></one-to-one>
</class>
</hibernate-mapping>
personaddress.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="personaddress" table="address_o"
dynamic-insert="true" dynamic-update="true"
select-before-update="false">
<id name="id" column="A_ID" type="integer">
<generator class="increment" />
</id>
<property name="addressLine1" column="ADDRESS_LINE_1"
type="string" />
<property name="city" column="CITY" type="string" />
<property name="state" column="STATE" type="string" />
<property name="zipCode" column="ZIPCODE" type="integer" />
<!-- In One-to-one we cannot specify the foreign key column
that has to be filled up
<one-to-one name="person" class="PersonOTO_B" cascade="all"
constrained="true"> </one-to-one>
-->
<many-to-one name="person" column="P_ID" unique="true"
not-null="true" lazy="false" />
</class>
</hibernate-mapping>
我的输出是:
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Hibernate: select max(P_ID) from persons_o
Primary Key : 1
---going for sleep--- (i am checking my db at this point but no data found )
Hibernate: select max(A_ID) from address_o
Primary Key again : 1
Hibernate: insert into persons_o (NAME, AGE, P_ID) values (?, ?, ?)
Hibernate: insert into address_o (ADDRESS_LINE_1, CITY, STATE, ZIPCODE, P_ID, A_ID) values (?, ?, ?, ?, ?, ?)
请纠正我的知识。
谢谢
贾延德拉·巴特
最佳答案
session.save(Object)、sesson.saveOrUpdate(Object)等方法仅将任何 transient 对象转换为持久对象,
表示对象与当前 hibernate session 关联(实际上对象与 session 功能队列关联,例如插入队列,
更新队列等根据相应的操作)并获取hibernate生成的(由生成器类提供)id
如果它是一个新对象。它绝不意味着对象将立即映射到数据库上。
当当前 hibernate session 刷新或 hibernate 事务提交时,仅运行实际查询来映射对象数据
进入数据库。
关于java - hibernate中的save方法没有立即插入,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27738473/