Hibernate+JDBC实现批量插入、更新及删除的方法详解

2019-11-26 11:02:24

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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)：

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)

<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)

<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；

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

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)

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)

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：

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：

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)

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)

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：

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：

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。

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