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Hibernate+JDBC实现批量插入、更新及删除的方法详解

程序员文章站 2024-02-15 10:34:22
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...

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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