本文实例讲述了Hibernate JDBC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)：
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package com.anlw.util;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;import com.anlw.entity.Student;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf = conf.buildSessionFactory(st); try { sess = sf.openSession(); tx = sess.beginTransaction(); for (int i = 0; i < 10; i++) { Student s = new Student(); s.setAge(i + 1); s.setName("test"); sess.save(s); } tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().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)
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<property name="hibernate.jdbc.batch_size">2</property> |
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)
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<property name="hibernate.cache.use_second_level_cache">false</property> |
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；
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package com.anlw.util;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;import com.anlw.entity.Student;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf = conf.buildSessionFactory(st); try { sess = sf.openSession(); tx = sess.beginTransaction(); for (int i = 0; i < 10; i++) { Student s = new Student(); 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 (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
2. 绕过Hibernate，直接调用JDBC API
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package com.anlw.util;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().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(new Work() { @Override public void execute(Connection arg0) throws SQLException {//需要注意的是，不需要调用close()方法关闭这个连接 //通过JDBC API执行用于批量插入的sql语句 String sql = "insert into student(name,age) values(?,?)"; PreparedStatement ps = arg0.prepareStatement(sql); for(int i=0;i<10;i++){ ps.setString(1, "kobe"); ps.setInt(2,12); ps.addBatch(); } ps.executeBatch(); } }); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
注意：通过JDBC API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JDBC API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 | delete from? <ClassName> [where where_conditions]
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)
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package com.anlw.util;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().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 Query query = sess.createQuery("update Student set name = 'www'"); query.executeUpdate(); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
(2)方式2：(强烈不推荐)
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package com.anlw.util;import java.sql.Connection;import java.sql.SQLException;import java.sql.Statement;import org.hibernate.CacheMode;import org.hibernate.Query;import org.hibernate.ScrollMode;import org.hibernate.ScrollableResults;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;import com.anlw.entity.Student;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf = conf.buildSessionFactory(st); try { sess = sf.openSession(); tx = sess.beginTransaction(); //查询表中的所有数据 ScrollableResults student = sess.createQuery("from Student") .setCacheMode(CacheMode.IGNORE) .scroll(ScrollMode.FORWARD_ONLY); int count = 0; while(student.next()){ Student s = (Student)student.get(0); s.setName("haha"); if(++count%3 == 0){ sess.flush(); sess.clear(); } } tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().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JDBC API
(1)方式1：
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package com.anlw.util;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import java.sql.Statement;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().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(new Work() { @Override public void execute(Connection arg0) throws SQLException {//需要注意的是，不需要调用close()方法关闭这个连接 String sql = "update student set name = 'oracle'"; //创建一个Satement对象 Statement st = arg0.createStatement(); //调用JDBC的update进行批量更新 st.executeUpdate(sql); } }); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
(2)方式2：
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package com.anlw.util;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import java.sql.Statement;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().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(new Work() { @Override public void execute(Connection arg0) throws SQLException {//需要注意的是，不需要调用close()方法关闭这个连接 String sql = "update student set name = ? where name=?"; PreparedStatement ps = arg0.prepareStatement(sql); for(int i=0;i<10;i++){ ps.setString(1,"tom"); ps.setString(2, "oracle"); ps.addBatch(); } ps.executeBatch(); } }); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().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)
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package com.anlw.util;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().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 Query query = sess.createQuery("delete Student");//也可以是delete from，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 (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
(2)方式2：(强烈不推荐)
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package com.anlw.util;import java.sql.Connection;import java.sql.SQLException;import java.sql.Statement;import org.hibernate.CacheMode;import org.hibernate.Query;import org.hibernate.ScrollMode;import org.hibernate.ScrollableResults;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;import com.anlw.entity.Student;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf = conf.buildSessionFactory(st); try { sess = sf.openSession(); tx = sess.beginTransaction(); //查询表中的所有数据 ScrollableResults student = sess.createQuery("from Student") .setCacheMode(CacheMode.IGNORE) .scroll(ScrollMode.FORWARD_ONLY); int count = 0; while(student.next()){ Student s = (Student)student.get(0); sess.delete(s); } tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().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JDBC API
(1)方式1：
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package com.anlw.util;import java.sql.Connection;import java.sql.SQLException;import java.sql.Statement;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;import com.anlw.entity.Student;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf = conf.buildSessionFactory(st); try { sess = sf.openSession(); tx = sess.beginTransaction(); sess.doWork(new Work() { @Override public void execute(Connection arg0) throws SQLException { String sql = "delete from student where age > 5"; //mysql中删除语句不能省略from Statement st = arg0.createStatement(); st.executeUpdate(sql); } }); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
2)方式2：
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package com.anlw.util;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import java.sql.Statement;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.jdbc.Work;import org.hibernate.service.ServiceRegistry;import com.anlw.entity.Student;public class SessionUtil { Configuration conf = null; ServiceRegistry st = null; SessionFactory sf = null; Session sess = null; Transaction tx = null; public void HIbernateTest() { conf = new Configuration().configure(); st = new StandardServiceRegistryBuilder().applySettings(conf.getProperties()).build(); sf = conf.buildSessionFactory(st); try { sess = sf.openSession(); tx = sess.beginTransaction(); sess.doWork(new Work() { @Override public void execute(Connection arg0) throws SQLException { String sql = "delete from student where age = ?"; //mysql中删除语句不能省略from PreparedStatement ps = arg0.prepareStatement(sql); for(int i=0;i<10;i++){ if(i%2 == 0){ ps.setInt(1, i); ps.addBatch(); } ps.executeBatch(); } } }); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } } finally { sess.close(); sf.close(); } } public static void main(String[] args) { new SessionUtil().HIbernateTest(); }} |
希望本文所述对大家基于Hibernate的java程序设计有所帮助。
原文链接：http://blog.csdn.net/an_2016/article/details/51759890
