Java Hibernate生成的查询比正常情况下多
我正在开发一个小型spring+hibernate web项目。下面是它的一些片段 applicationContext.xmlJava Hibernate生成的查询比正常情况下多,java,mysql,spring,hibernate,Java,Mysql,Spring,Hibernate,我正在开发一个小型spring+hibernate web项目。下面是它的一些片段 applicationContext.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
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"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
<context:component-scan base-package="com.catb">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
<mvc:annotation-driven />
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close">
<property name="driverClass" value="com.mysql.jdbc.Driver" />
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/catb_db" />
<property name="user" value="root" />
<property name="password" value="root" />
</bean>
<bean id="hibernate4AnnotatedSessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="annotatedClasses">
<list>
<value>com.catb.model.User</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean>
<bean id="userDAO" class="com.catb.dao.impl.UserDAOImpl">
<property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
</bean>
UserDAO类
@Repository
public class UserDAOImpl implements UserDAO {
private SessionFactory sessionFactory;
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}
@Override
public boolean addUser(User user) {
Session session = sessionFactory.getCurrentSession();
session.save(user);
return true;
}
}
和UserBO类
@Override
@Transactional
public void addUser(User user) {
userDAO.addUser(user);
}
当我试图在控制器中使用userBO.addUser(user)插入单个用户时,我间歇性地遇到一个this错误
org.hibernate.exception.ConstraintViolationException: could not execute statement
org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:72)
org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
...
caused by
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '60' for key 'username'
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
我知道这个错误是由于在唯一字段(用户名)中插入了一个具有重复值的新行引起的。但是,当我试图通过Hibernate的show_sql进行调试时,它打印出了两行而不是一行(我只插入了一个用户)
显然,第二次插入导致了异常,因为它添加了与第一次相同的值
有人能告诉我为什么会出现这个错误以及如何解决它吗
提前感谢尝试将日志添加到
addUser
服务方法中,因为该服务似乎被调用了两次
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对于您当前的配置,Hibernate对INSERT没有其他解释。您确定发布了所有相关代码吗?日志中提到了一个
position\u id
,但是您没有发布任何与position
相关的内容,可能存在一些映射问题。当然,您可以将User
实体剥离到您发布的字段(用户名和密码),看看它是否仍然导致异常。我已经向dao和服务方法添加了日志。这些只调用一次。同时添加多个用户时,此错误发生的频率更高。例如:当我调用addUser()n次时,show_sql打印n+1次,所以它不是2n而是n+1。真奇怪,对不起,我弄错了。事实上,我的用户实体还有一些其他字段,但我想缩短代码以便于阅读。我修正了我的密码
@Override
@Transactional
public void addUser(User user) {
userDAO.addUser(user);
}
org.hibernate.exception.ConstraintViolationException: could not execute statement
org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:72)
org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
...
caused by
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '60' for key 'username'
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
Hibernate: insert into user (id, password, username) values (?, ?, ?)
Hibernate: insert into user (id, password, username) values (?, ?, ?)