我正在尝试实现乐观锁定，以避免丢失更新的情况。在我的应用中，当两个用户获取相同的记录并且第一个用户使用一些更改进行更新时，第二个用户看到相同的记录却无法看到第一个人的更改，并自己进行了一些更改并更新了它。由此导致了第一个人的更改被覆盖。为了防止这种情况，我编写了以下代码，但问题仍然存在。我对这个概念还很陌生，无法确定问题所在。
我尝试通过阅读doc 11.3.4.自定义自动版本控制部分来实现这一点。
我尝试通过阅读doc 11.3.4.自定义自动版本控制部分来实现这一点。
The configuration file
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <tx:annotation-driven transaction-manager="txManager"/> <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"/> </bean> <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate"> <property name="sessionFactory" ref="sessionFactory"/> </bean> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="annotatedClasses"> <list> <value>server.bo.Dept</value> <value>server.bo.Emp</value> </list> </property> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">org.hibernate.dialect.SQLServer2008Dialect</prop> <prop key="hibernate.show_sql">false</prop> </props> </property> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="net.sourceforge.jtds.jdbc.Driver"/> <property name="url" value="${db.url}"/> <property name="username" value="${db.username}"/> <property name="password" value="${db.password}"/> </bean> <bean id="deptDAO" class="server.dao.DeptDAOImpl"> <property name="hibernateTemplate" ref="hibernateTemplate"/> </bean> </beans>Entity Class
@Entity @Table(name = "Dept") @org.hibernate.annotations.Entity(dynamicUpdate = true,optimisticLock = OptimisticLockType.ALL) public class Dept{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "ID") Long id; @OneToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER, mappedBy = "deptId") @Fetch(FetchMode.SELECT) @OrderBy(value = "id DESC") List<Emp> Emplist; public Dept() {} // Getters and setters }DAO Impl
public class DeptDAOImpl extends HibernateDaoSupport implements DeptDAO { @Transactional(readOnly = true, propagation = Propagation.REQUIRED, isolation = Isolation.REPEATABLE_READ) public Dept getDeptById(Long id) { Object param[] = new Object[]{id}; String query = "select d from Dept d where d.id=? and d.deleted='0'"; List<Dept> deptDetailsList = getHibernateTemplate().find(query,param); Dept deptDetails = null; if(deptDetailsList !=null && deptDetailsList .size()>0) deptDetails = (Dept)deptDetailsList.get(0); return deptDetails ; } @Transactional(readOnly = false, propagation = Propagation.REQUIRED, isolation = Isolation.REPEATABLE_READ) public long updateDept(Dept dept) { if (dept.getId() == null) { getSession().save(dept); } else { getSession().update(dept); } if (dept.getEmplist() != null) { final int size = dept.getEmplist().size(); for (int i = size - 1; i >= 0; i--) { Emp emp = dept.getEmplist().get(i); if (emp.getDeptId() == null) { emp.setDeptId(dept.getId()); } if (RecordStatus.NEW.equals(emp.getRecordStatus())) { getSession().save(emp); } else if (RecordStatus.DELETED.equals(emp.getRecordStatus())) { getSession().delete(emp); } else if (RecordStatus.MODIFIED.equals(emp.getRecordStatus())) { getSession().update(emp); } } } return dept.getId(); } }
提前感谢