Hibernate+JDBC实现批量插入、更新及删除的方法详解
本文实例讲述了HibernateJDBC实现批量插入、更新及删除的方法。分享给大家供大家参考,具体如下:
一、批量插入(两种方式)
1.通过Hibernate缓存
如果这样写代码进行批量插入(初始设想):
packagecom.anlw.util; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.service.ServiceRegistry; importcom.anlw.entity.Student; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); for(inti=0;i<10;i++){ Students=newStudent(); s.setAge(i+1); s.setName("test"); sess.save(s); } tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
如果数据量太大,会有可能出现内存溢出的异常;
小知识:
(1).Hibernate一级缓存,对其容量没有限制,强制使用,由于所有的对象都被保存到这个缓存中,内存总会达到一定数目时出现内存溢出的情况;
(2).Hibernate二级缓存可以进行大小配置;
要解决内存溢出的问题,就应该定时的将Sessiion缓存中的数据刷到数据库,正确的批量插入方式:
(1).设置批量尺寸(博主至今还没有明白下面这个属性和flush()方法的区别)
2
配置这个参数的原因就是尽量少读数据库,该参数值越大,读数据库的次数越少,速度越快;上面这个配置,是Hibernate是等到程序积累了100个sql之后在批量提交;
(2).关闭二级缓存(这个博主也不是很明白)
false
除了Session级别的一级缓存,Hibernate还有一个SessionFactory级别的二级缓存,如果启用了二级缓存,从机制上来说,Hibernate为了维护二级缓存,在批量插入时,hibernate会将对象纳入二级缓存,性能上就会有很大损失,也可能引发异常,因此最好关闭SessionFactory级别的二级缓存;
(3).在一二设置完成的基础上,清空Session级别的一级缓存;
packagecom.anlw.util; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.service.ServiceRegistry; importcom.anlw.entity.Student; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); for(inti=0;i<10;i++){ Students=newStudent(); s.setAge(i+1); s.setName("test"); sess.save(s); if(i%100==0){//以每100个数据作为一个处理单元 sess.flush();//保持与数据库数据的同步 sess.clear();//清楚Session级别的一级缓存的全部数据,及时释放占用的内存 } } tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
2.绕过Hibernate,直接调用JDBCAPI
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.PreparedStatement; importjava.sql.SQLException; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //执行Work对象指定的操作,即调用Work对象的execute()方法 //Session会把当前使用的数据库连接传给execute()方法 sess.doWork(newWork(){ @Override publicvoidexecute(Connectionarg0)throwsSQLException{//需要注意的是,不需要调用close()方法关闭这个连接 //通过JDBCAPI执行用于批量插入的sql语句 Stringsql="insertintostudent(name,age)values(?,?)"; PreparedStatementps=arg0.prepareStatement(sql); for(inti=0;i<10;i++){ ps.setString(1,"kobe"); ps.setInt(2,12); ps.addBatch(); } ps.executeBatch(); } }); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
注意:通过JDBCAPI中的PreparedStatement接口来执行sql语句,sql语句涉及到的数据不会被加载到Session的缓存中,因此不会占用内存空间,因此直接调用JDBCAPI批量化插入的效率要高于Hibernate缓存的批量插入;
更新&&删除
语法格式:(HQL)
update | deletefrom?
1>在from子句中,from关键字是可选的,即完全可以不写from关键字
2>在from子句中,只能有一个类名,可以在该类名后指定别名
3>不能在批量HQL语句中使用连接,显示或者隐式的都不行,但可以在where子句中使用子查询
4>整个where子句是可选的,where子句的语法sql语句中where子句的语法完全相同
5>Query.executeUpdate()方法返回一个整型值,该值是受此操作影响的记录数量,由于hibernate的底层操作实际上是由JDBC完成的,因此,如果有批量update或delete操作被转换成多条update或delete语句,(关联或者继承映射),该方法只能返回最后一条sql语句影响的记录行数,不是所有的记录行数,需要注意;
二、批量更新(两种方式)
1.使用Hibernate直接进行批量更新
(1)方式1:(Hibernate的HQL直接支持update/delete的批量更新语法)
packagecom.anlw.util; importorg.hibernate.Query; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.service.ServiceRegistry; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //在HQL查询中使用update进行批量更新,下面的的语句是HQL语句,不是sql语句 Queryquery=sess.createQuery("updateStudentsetname='www'"); query.executeUpdate(); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
(2)方式2:(强烈不推荐)
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.SQLException; importjava.sql.Statement; importorg.hibernate.CacheMode; importorg.hibernate.Query; importorg.hibernate.ScrollMode; importorg.hibernate.ScrollableResults; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; importcom.anlw.entity.Student; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //查询表中的所有数据 ScrollableResultsstudent=sess.createQuery("fromStudent") .setCacheMode(CacheMode.IGNORE) .scroll(ScrollMode.FORWARD_ONLY); intcount=0; while(student.next()){ Students=(Student)student.get(0); s.setName("haha"); if(++count%3==0){ sess.flush(); sess.clear(); } } tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
通过这种方式,虽然可以执行批量更新,但效果非常不好,执行效率不高,需要先执行数据查询,然后再执行数据更新,而且这种更新将是逐行更新,即每更新一行记录,都要执行一条update语句,性能非常低;
2.绕过Hibernate,调用JDBCAPI
(1)方式1:
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.PreparedStatement; importjava.sql.SQLException; importjava.sql.Statement; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //执行Work对象指定的操作,即调用Work对象的execute()方法 //Session会把当前使用的数据库连接传给execute()方法 sess.doWork(newWork(){ @Override publicvoidexecute(Connectionarg0)throwsSQLException{//需要注意的是,不需要调用close()方法关闭这个连接 Stringsql="updatestudentsetname='oracle'"; //创建一个Satement对象 Statementst=arg0.createStatement(); //调用JDBC的update进行批量更新 st.executeUpdate(sql); } }); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
(2)方式2:
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.PreparedStatement; importjava.sql.SQLException; importjava.sql.Statement; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //执行Work对象指定的操作,即调用Work对象的execute()方法 //Session会把当前使用的数据库连接传给execute()方法 sess.doWork(newWork(){ @Override publicvoidexecute(Connectionarg0)throwsSQLException{//需要注意的是,不需要调用close()方法关闭这个连接 Stringsql="updatestudentsetname=?wherename=?"; PreparedStatementps=arg0.prepareStatement(sql); for(inti=0;i<10;i++){ ps.setString(1,"tom"); ps.setString(2,"oracle"); ps.addBatch(); } ps.executeBatch(); } }); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
三、批量删除(两种方式)
1.使用Hibernate直接进行批量删除
(1)方式1:(Hibernate的HQL直接支持update/delete的批量更新语法)
packagecom.anlw.util; importorg.hibernate.Query; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.service.ServiceRegistry; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //在HQL查询中使用delete进行批量删除,下面的的语句是HQL语句,不是sql Queryquery=sess.createQuery("deleteStudent");//也可以是deletefrom,from关键字是可选的,可以不要,加条件的时候可以指定类的别名 query.executeUpdate(); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
(2)方式2:(强烈不推荐)
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.SQLException; importjava.sql.Statement; importorg.hibernate.CacheMode; importorg.hibernate.Query; importorg.hibernate.ScrollMode; importorg.hibernate.ScrollableResults; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; importcom.anlw.entity.Student; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); //查询表中的所有数据 ScrollableResultsstudent=sess.createQuery("fromStudent") .setCacheMode(CacheMode.IGNORE) .scroll(ScrollMode.FORWARD_ONLY); intcount=0; while(student.next()){ Students=(Student)student.get(0); sess.delete(s); } tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
通过这种方式,虽然可以执行批量删除,但效果非常不好,执行效率不高,需要先执行数据查询,然后再执行数据删除,而且这种删除将是逐行删除,即每删除一行记录,都要执行一条delete语句,性能非常低;
2.绕过Hibernate,调用JDBCAPI
(1)方式1:
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.SQLException; importjava.sql.Statement; importorg.hibernate.Query; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; importcom.anlw.entity.Student; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); sess.doWork(newWork(){ @Override publicvoidexecute(Connectionarg0)throwsSQLException{ Stringsql="deletefromstudentwhereage>5";//mysql中删除语句不能省略from Statementst=arg0.createStatement(); st.executeUpdate(sql); } }); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
2)方式2:
packagecom.anlw.util; importjava.sql.Connection; importjava.sql.PreparedStatement; importjava.sql.SQLException; importjava.sql.Statement; importorg.hibernate.Query; importorg.hibernate.Session; importorg.hibernate.SessionFactory; importorg.hibernate.Transaction; importorg.hibernate.boot.registry.StandardServiceRegistryBuilder; importorg.hibernate.cfg.Configuration; importorg.hibernate.jdbc.Work; importorg.hibernate.service.ServiceRegistry; importcom.anlw.entity.Student; publicclassSessionUtil{ Configurationconf=null; ServiceRegistryst=null; SessionFactorysf=null; Sessionsess=null; Transactiontx=null; publicvoidHIbernateTest(){ conf=newConfiguration().configure(); st=newStandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf=conf.buildSessionFactory(st); try{ sess=sf.openSession(); tx=sess.beginTransaction(); sess.doWork(newWork(){ @Override publicvoidexecute(Connectionarg0)throwsSQLException{ Stringsql="deletefromstudentwhereage=?";//mysql中删除语句不能省略from PreparedStatementps=arg0.prepareStatement(sql); for(inti=0;i<10;i++){ if(i%2==0){ ps.setInt(1,i); ps.addBatch(); } ps.executeBatch(); } } }); tx.commit(); }catch(Exceptione){ if(tx!=null){ tx.rollback(); } }finally{ sess.close(); sf.close(); } } publicstaticvoidmain(String[]args){ newSessionUtil().HIbernateTest(); } }
希望本文所述对大家基于Hibernate的java程序设计有所帮助。