org.hibernate.MappingException： <mapping> 配置中的元素未指定任何已知属性

Question

当我运行代码时，它给了我一个例外：

org.hibernate.MappingException：配置中的元素未指定任何已知属性

我不确定错误发生在哪里，任何人都可以帮我解决这个问题。

hibernate.cfg.xml

     <hibernate-configuration>
     <session-factory>
     <property name="hbm2ddl.auto">create</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">"url"</property>
<property name="hibernate.connection.username">"username"</property>
<property name="hibernate.connection.password">"password"</property>
<mapping resource="student.hbm.xml"/>
<mapping/>

学生.java

public class Student {

private String name;
 private int id;

public String getName() {
    return name;
}

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

public int getId() {
    return id;
}

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

}

Regular.java

 public class Regular extends Student {

String coursefees;

public String getCoursefees() {
    return coursefees;
}

public void setCoursefees(String coursefees) {
    this.coursefees = coursefees;
}

}

遥远的java

 public class Distant extends Student {

String distantfees;

public String getDistantfees() {
    return distantfees;
}

public void setDistantfees(String distantfees) {
    this.distantfees = distantfees;
}

}

student.hbm.xml

       <!DOCTYPE hibernate-mapping PUBLIC
      "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
       "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

       <hibernate-mapping>


       <class name="pojos.Student" table="student" discriminator-       value="student">  
       <id name="id" type="int">  
       <column name="id"/>
       <generator class="increment"></generator>  
       </id>  

       <discriminator column="type" type="string"></discriminator>  
       <property name="name" type="string">
       <column name="sname"/>
        </property>

     <subclass name="pojos.Regular" discriminator-value="regstud">  
     <property name="coursefees" type="string">
     <column name="coursefees"/>
     </property>  
    </subclass>   

   <subclass name="pojos.Distant" discriminator-value="distant">  
   <property name="distantfees" type="string">
  <column name="distfees"/>
  </property>  
  </subclass>

 </class>

 </hibernate-mapping>

错误：

线程“主”中的异常org.hibernate.MappingException：配置中的元素在org.hibernate.cfg.Configuration.parseSessionFactory（Configuration.java）的org.hibernate.cfg.Configuration.parseMappingElement（Configuration.java:2286）处未指定任何已知属性：2227），位于org.hibernate.cfg.Configuration.doConfigure（Configuration.java:2207），位于org.hibernate.cfg.Configuration.doConfigure（Configuration.java:2160），位于org.hibernate.cfg.Configuration.configure（Configuration。 java：2075）

Answer 1

删除hibernate.cfg.xml文件末尾的空<mapping/>