求救：加了前缀属性就无法运行

上面是我的代码

加了前缀属性就无法运行，注释掉就正常

我是跟着老师的视频走的，其他代码一致

求大神拯救

ps:加了前缀属性后

最后给一个

ERROR: HHH000099: an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session): org.hibernate.AssertionFailure: null id in pojo.Student entry (don't flush the Session after an exception occurs)

啥意思？

我手动设置id=1不行，id为null不行，不设置id也不行

不要前缀属性就咋都行（设置id没有用，自动增长的）

package pojo;

import java.util.Date;

public class Student implements java.io.Serializable {

	// Fields

	private int id;
	private String name;
	private String gender;
	private Date birthday;
	private String address;

	// Constructors

	/** default constructor */
	public Student() {
	}

	/** full constructor */
	public Student(String name, String gender, Date birthday, String address) {
		this.name = name;
		this.gender = gender;
		this.birthday = birthday;
		this.address = address;
	}

	// Property accessors

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getGender() {
		return this.gender;
	}

	public void setGender(String gender) {
		this.gender = gender;
	}

	public Date getBirthday() {
		return this.birthday;
	}

	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

	public String getAddress() {
		return this.address;
	}

	public void setAddress(String address) {
		this.address = address;
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", gender=" + gender
				+ ", birthday=" + birthday + ", address=" + address + "]";
	}
	
	
}

上面是类
下面是映射

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="pojo.Student" table="student" catalog="xiele007">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="16" />
        </property>
        <property name="gender" type="java.lang.String">
            <column name="gender" length="32" />
        </property>
        <property name="birthday" type="java.util.Date">
            <column name="birthday" length="10" />
        </property>
        <property name="address" type="java.lang.String">
            <column name="address" />
        </property>
    </class>
</hibernate-mapping>