SSH整合框架中save方法执行的时候会删除原有数据
如:
Hibernate: delete from stu_tea where tea_id=?
Hibernate: insert into stu_tea (tea_id, stu_id) values (?, ?)
我用的实体类注解方式,多对多关联关系,学生和老师类,执行save的时候每次中间表的关联关系都会被新的关联关系覆盖,看sql语句输出是现实先把原来的删除了,再添加的,检查过自己的配置update这个确定是update不是create;
学生类
package com.cdd.ssh.entity;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
@Entity
public class Students {
@Id
@Column(name="sId")//可省略
//设置主键自增
@GeneratedValue(strategy = GenerationType.AUTO)
private int sId;
private String sName;
private String sSex;
private int sAge;
@ManyToMany(mappedBy="students",cascade={CascadeType.PERSIST})
private Set<Teachers> teachers = new HashSet<Teachers>();
public int getsId() {
return sId;
}
public void setsId(int sId) {
this.sId = sId;
}
public String getsName() {
return sName;
}
public void setsName(String sName) {
this.sName = sName;
}
public String getsSex() {
return sSex;
}
public void setsSex(String sSex) {
this.sSex = sSex;
}
public int getsAge() {
return sAge;
}
public void setsAge(int sAge) {
this.sAge = sAge;
}
public Set<Teachers> getTeachers() {
return teachers;
}
public void setTeachers(Set<Teachers> teachers) {
this.teachers = teachers;
};
}
老师类
package com.cdd.ssh.entity;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;
@Entity
//注明实体类对应表明,省略默认使用类名
@Table(name="teachers")
public class Teachers {
//表明id列
@Id
@Column(name="tId")//可省略
//设置主键自增
@GeneratedValue(strategy = GenerationType.AUTO)
private int tId;
private String tType;//科目
private String tName;//姓名
@ManyToMany(cascade={CascadeType.PERSIST,CascadeType.MERGE})
//设置中间表关联关系
@JoinTable(name="stu_tea",
joinColumns ={@JoinColumn(name = "tea_id")},
inverseJoinColumns={@JoinColumn(name="stu_id")})
private Set<Students> students = new HashSet<Students>();
public int gettId() {
return tId;
}
public void settId(int tId) {
this.tId = tId;
}
public String gettType() {
return tType;
}
public void settType(String tType) {
this.tType = tType;
}
public String gettName() {
return tName;
}
public void settName(String tName) {
this.tName = tName;
}
public Set<Students> getStudents() {
return students;
}
public void setStudents(Set<Students> students) {
this.students = students;
}
}
这个是dao中的执行方法
public void add(Students student, Teachers teacher) {
// TODO Auto-generated method stub
Session session = this.getSession();
student.getTeachers().add(teacher);
teacher.getStudents().add(student);
session.save(teacher);
session.save(student);
System.out.println(teacher.gettId());
System.out.println(student.getsId());
}
这是我的代码,求大神帮忙啊,一下午了都没弄好,
在这之前我是写的学生和教室类,后来感觉教室不合适,就把教室改成老师类了,配置文件和属性都没有改变,只把用到教室的地方换成了老师;
求大神帮忙
这里是applicationContext.xml的全部配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-2.5.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd
">
<!-- 开启注解 -->
<context:annotation-config/>
<!-- 扫描包设置 -->
<context:component-scan base-package="com.cdd.ssh.*"></context:component-scan>
<!--DateSource数据源 使用DBCP连接池-->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/school?useUnicode=true&characterEncoding=UTF8"/>
<property name="username" value="root"/>
<property name="password" value="chengzi"/>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource"></property>
<!-- 载入实体类 mappingResources -->
<property name="packagesToScan">
<value>com.cdd.ssh.entity</value>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
</props>
</property>
</bean>
<!-- 3.~~~~~~~~~~~~~~~~~~~~~~~~~事务配置~~~~~~~~~~~~~~~~~~~~~~~~~~~~-->
<bean id="txManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager" >
<property name="sessionFactory" ref="sessionFactory"></property>
</bean>
<tx:annotation-driven transaction-manager="txManager" />
<aop:config>
<aop:pointcut expression="execution(public * com.cdd.ssh.service.*.*(..))"
id="bussinessService"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="bussinessService" />
</aop:config>
<tx:advice id="txAdvice" transaction-manager="txManager" >
<tx:attributes>
<tx:method name="query*" read-only="true" propagation="NOT_SUPPORTED" />
<!-- get开头的方法不需要在事务中运行 。
有些情况是没有必要使用事务的，比如获取数据。开启事务本身对性能是有一定的影响的-->
<tx:method name="*"/> <!-- 其他方法在实务中运行 -->
</tx:attributes>
</tx:advice>
</beans>
