如何在 Hibernate 应用程序中处理数据库空值？
由于数据库表中的空值，我收到“org.hibernate.PropertyAccessException”。异常如何处理？
我的文件是
获取测试.java
package com.raj.java.hiberanteDemos;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class FetchTest {
public static void main(String[] args) {
Configuration cfg=new Configuration().configure("hibernate.cfg.xml");
SessionFactory factory=cfg.buildSessionFactory();
Session session1=factory.openSession();
Employee emp1=(Employee)session1.get(Employee.class,7839);
System.out.println(emp1.getEmpno()+" "+emp1.getEname()+" "+emp1.getSal());
session1.close();
Session session2=factory.openSession();
Employee emp2=(Employee)session2.load(Employee.class,7839);
System.out.println(emp2.getEmpno()+" "+emp2.getEname()+" "+emp2.getSal());
session2.close();
}
}员工.java
package com.raj.java.hiberanteDemos;
import java.sql.Date;
class Employee {
private int empno, mgr, deptnumber;
private String ename, job;
private double sal, comm;
private Date hiredate;
public int getEmpno() {
return empno;
}
public void setEmpno(int empno) {
this.empno = empno;
}
public int getMgr() {
return mgr;
}
public void setMgr(int mgr) {
this.mgr = mgr;
}
public int getDeptnumber() {
return deptnumber;
}
public void setDeptnumber(int deptnumber) {
this.deptnumber = deptnumber;
}
public String getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
public double getComm() {
return comm;
}
public void setComm(double comm) {
this.comm = comm;
}
public Date getHiredate() {
return hiredate;
}
public void setHiredate(Date hiredate) {
this.hiredate = hiredate;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public double getSal() {
return sal;
}
public void setSal(double sal) {
this.sal = sal;
}
}休眠配置文件
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hbm2ddl.auto">update</property>
<property name="dialect">org.hibernate.dialect.Oracle9Dialect
</property>
<property name="connection.url">someValidurl</property>
<property name="connection.username">username</property>
<property name="connection.password">password</property>
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.show_sql">true</property>
<property name="cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<property name="hibernate.cache.use_second_level_cache">true</property>
<mapping resource="employee.hbm.xml"></mapping>
</session-factory>
</hibernate-configuration>员工.hbm.xml
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!-- <class name="com.javatpoint.mypackage.Employee" table="employee"> <id
name="empid"> <generator class="assigned"></generator> </id> <property name="firstName"></property>
<property name="lastName"></property> </class> -->
<class name="com.raj.java.hiberanteDemos.Employee" table="emp">
<id name="empno" type="int" column="EMPNO">
<generator class="increment" />
</id>
<property name="ename" type="java.lang.String" />
<property name="mgr" type="int" />
<property name="deptnumber" type="int" column="deptno" />
<property name="job" type="java.lang.String" />
<property name="sal" type="double" />
<property name="comm" type="double" />
<property name="hiredate" type="java.sql.Date" />
</class>
</hibernate-mapping>当我运行此应用程序时，我收到以下错误消息。
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select employee0_.EMPNO as EMPNO0_0_, employee0_.ename as ename0_0_, employee0_.mgr as mgr0_0_, employee0_.deptno as deptno0_0_, employee0_.job as job0_0_, employee0_.sal as sal0_0_, employee0_.comm as comm0_0_, employee0_.hiredate as hiredate0_0_ from emp employee0_ where employee0_.EMPNO=?
Exception in thread "main" org.hibernate.PropertyAccessException: exception setting property value with CGLIB (set hibernate.cglib.use_reflection_optimizer=false for more info) setter of com.raj.java.hiberanteDemos.Employee.setMgr
at org.hibernate.tuple.PojoEntityTuplizer.setPropertyValuesWithOptimizer(PojoEntityTuplizer.java:215)
at org.hibernate.tuple.PojoEntityTuplizer.setPropertyValues(PojoEntityTuplizer.java:185)
at org.hibernate.persister.entity.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:3232)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:129)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:842)
at org.hibernate.loader.Loader.doQuery(Loader.java:717)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1785)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:47)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:41)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2730)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:177)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:87)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862)
at org.hibernate.impl.SessionImpl.get(SessionImpl.java:799)
at org.hibernate.impl.SessionImpl.get(SessionImpl.java:792)
at com.raj.java.hiberanteDemos.FetchTest.main(FetchTest.java:13)
Caused by: net.sf.cglib.beans.BulkBeanException
at com.raj.java.hiberanteDemos.Employee$$BulkBeanByCGLIB$$142cfd75.setPropertyValues(<generated>)
at org.hibernate.tuple.PojoEntityTuplizer.setPropertyValuesWithOptimizer(PojoEntityTuplizer.java:212)
... 19 more
Caused by: java.lang.NullPointerException
... 21 more我的 emp 表数据
当我用 0 或其他一些值更新所有空值时，它工作正常。
请帮助我解决错误而不更新数据库表中的空值。
提前致谢，拉杰
我个人建议实际“清理”数据库值，也许将列设置为不可为空。
但如果无法做到这一点，您可以做的是修改您的设置器，以便它检查null：
public void setComm(Double comm) {
if(null != comm){
this.comm = comm;
}else{
this.comm = 0;
}
}
希望这可以帮助