Question

我正在使用Oracle数据库。我们看到我们的服务电话频繁失败。当我查看日志时，我看到表格中出现以下异常

java.sql.BatchUpdateException：ORA-00001：唯一约束

我们实施了主键生成。

请找到代码

<class name="com.dvo.History" table="HISTORY" >
        <id name="hiId" type="java.lang.Long">
            <column name="HI_ID" precision="22" scale="0" />
           <generator class="com.radiant.cisms.hibernate.generator.SequenceGenerator">      
                <param name="TABLE_NAME">HISTORY</param>
            </generator>
        </id>

类文件

package com.generator;

import java.io.Serializable;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.Configurable;
import org.hibernate.id.IdentifierGenerator;
import org.hibernate.type.Type;


public class SequenceGenerator implements IdentifierGenerator, Configurable {


    private static Logger logger = Logger.getLogger(SequenceGenerator.class);

    String tableName;

    public void configure(Type arg0, Properties arg1, Dialect arg2)throws MappingException {
        tableName = arg1.getProperty("TABLE_NAME");
    }


    public Serializable generate(SessionImplementor arg0, Object arg1)throws HibernateException {
        return getNextValue(arg0);
    }


    public Serializable getNextValue(SessionImplementor session){
        Long nextValue = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        try{
            Connection connection = session.connection();
            preparedStatement = connection.prepareStatement("SELECT SEQ_GENERATOR_VALUE FROM SEQ_GENERATOR WHERE SEQ_GENERATOR_TABLE = ?");
            preparedStatement.setString(1, tableName);
            resultSet = preparedStatement.executeQuery();
            while(resultSet.next()){
                nextValue = resultSet.getLong("SEQ_GENERATOR_VALUE");
            }
            resultSet.close();
            preparedStatement.close();
            preparedStatement = connection.prepareStatement("UPDATE SEQ_GENERATOR SET SEQ_GENERATOR_VALUE = ? WHERE SEQ_GENERATOR_TABLE = ?");
            preparedStatement.setLong(1, nextValue+1);
            preparedStatement.setString(2, tableName);
            preparedStatement.executeUpdate();
        } catch(SQLException e){
            logger.debug(e.getMessage());
        } catch(Exception e){
            logger.debug(e.getMessage());
        }
        finally{

            try{
                resultSet.close();
                preparedStatement.close();
            } catch(SQLException e){
                logger.debug(e.getMessage());
            }
        }
        return nextValue;
    }

}

我们正在用oracle sequence替换这段代码

Answer 1

将synchronized添加到你的getNextValue方法。

 synchronized public Serializable getNextValue(SessionImplementor session)

测试并告诉我结果应该有效。

Answer 2

您需要在从seq_generator表中选择时创建独占锁。

试试这个

preparedStatement = connection.prepareStatement("SELECT SEQ_GENERATOR_VALUE FROM SEQ_GENERATOR WHERE SEQ_GENERATOR_TABLE = ? FOR UPDATE");

当然必须在getNextValue方法结束时完成提交

java.sql.BatchUpdateException：ORA-00001：生成主键时的唯一约束

2 个答案: