Hibernate 由以下原因引起的异常:java.sql.SQLException:一般错误,来自服务器的消息:";字段';empid&x27;不';“没有默认值”;
我的模型课:Hibernate 由以下原因引起的异常:java.sql.SQLException:一般错误,来自服务器的消息:";字段';empid&x27;不';“没有默认值”;,hibernate,Hibernate,我的模型课: package com.igate.model; import java.util.Date; //import java.sql.Date; import java.sql.Timestamp; import javax.persistence.Column; import javax.persistence.Entity; import javax.persist
package com.igate.model;
import java.util.Date;
//import java.sql.Date;
import java.sql.Timestamp;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="Employee")
public class Employee
{
@Id
@Column(name="empid")
@GeneratedValue(strategy=GenerationType.IDENTITY)
int id;
@Column(name="empname")
String name;
String job;
Date hiredate;
int sal;
int deptid;
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 getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
public Date getHiredate() {
return hiredate;
}
public void setHiredate(Date hiredate) {
this.hiredate = hiredate;
}
public int getSal() {
return sal;
}
public void setSal(int sal) {
this.sal = sal;
}
public int getDeptid() {
return deptid;
}
public void setDeptid(int deptid) {
this.deptid = deptid;
}
public void setHiredate(Timestamp hiredate) {
this.hiredate = hiredate;
}
}
我的cfg文件:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!--connection properties -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="connection.username">root</property>
<property name="connection.password">MenhiBaba</property>
<!--hibernate properties -->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hb2ddl.auto">validate</property>
<property name="show_sql">true</property>
<!-- <property name="use_sql_comments">true</property>
<property name="format_sql">true</property>
-->
<!-- Resource mapping -->
<mapping class="com.igate.model.Employee"/>
</session-factory>
</hibernate-configuration>
主要方法:
import java.sql.Date;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.igate.model.Employee;
import com.igate.utils.HibernateUtils;
public class Test
{
public static void main(String[] args) {
Session session =null;
Transaction txn = null;
try
{
session = HibernateUtils.getSessionFactory().openSession();
txn = session.beginTransaction();
txn.begin();
Employee emp = new Employee();
emp.setId(101);
emp.setName("Rahim");
emp.setJob("PO");
emp.setHiredate(new Date(24-11-2011));
emp.setSal(5500);
emp.setDeptid(20);
int i=(Integer)session.save(emp);
if(i>=0)
System.out.println("data saved");
else
System.out.println("data not saved");
txn.commit();
session.close();
}catch(Exception e)
{
System.out.println("problem in creating session object");
throw new ExceptionInInitializerError(e);
}
}
}
在此之前,我执行了许多程序,但我没有遇到任何问题。但我不知道我的代码有什么问题。我花了2个小时在这个简单的程序上。请问有人能帮我吗
提前谢谢 如果希望自动分配自动递增字段,请将其设置为NULL或0。有关更多详细信息,请参见为什么要使用
emp.setId(101)为自动生成的字段赋值代码>?在创建关联表时,您似乎忘记在MySQL中添加自动增量
。因此,@GeneratedValue(strategy=GenerationType.IDENTITY)
不会自动生成密钥。如果我们不在本例中使用,Hibernate将自动创建密钥。我分配了emp.setId(101)如果前端使用了@GeneratedValue(strategy=GenerationType.IDENTITY)
,则后端需要一个自动生成的主键创建表Employee(id int(11)unsigned not NULL auto_INCREMENT…
。但是,如果您不需要自动生成的密钥,则将其放在两侧-Hibernate和MySQL,并手动分配一个id
,如emp.setId(101)代码>,当要持久化与该表中的行对应的实体时。
import java.sql.Date;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.igate.model.Employee;
import com.igate.utils.HibernateUtils;
public class Test
{
public static void main(String[] args) {
Session session =null;
Transaction txn = null;
try
{
session = HibernateUtils.getSessionFactory().openSession();
txn = session.beginTransaction();
txn.begin();
Employee emp = new Employee();
emp.setId(101);
emp.setName("Rahim");
emp.setJob("PO");
emp.setHiredate(new Date(24-11-2011));
emp.setSal(5500);
emp.setDeptid(20);
int i=(Integer)session.save(emp);
if(i>=0)
System.out.println("data saved");
else
System.out.println("data not saved");
txn.commit();
session.close();
}catch(Exception e)
{
System.out.println("problem in creating session object");
throw new ExceptionInInitializerError(e);
}
}
}