java 并发插入数据到oracle 博客分类： javaoracle java并发多线程迁移数据

各位技术大牛，请教java 多线程问题

由于项目需要，需要从oracle中dept将表记录迁移到dept2中，dept和dept2表结构一样。
设想:

查询：
Statement stmt = conn.createStatement(
            ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);

ResultSet rs = stmt.executeQuery("select * from dept");

通过 rs.last();得到记录的总个数，然后通过这个总个数，多线程实现迁移所有的记录。

插入：
PreparedStatement pstmt = null;
        String psql = "insert into dept2 values(?,?,?)";
        pstmt = conn.prepareStatement(psql);

其中的index为rs结果集的索引值，当index=1，表示rs.next（）的第一个值
                    rs.absolute(index);
                    pstmt.setInt(1, rs.getInt(1));
                    pstmt.setString(2, rs.getString(2));
                    pstmt.setString(3, rs.getString(3));

                    pstmt.addBatch();

本人对多线程不是很了解，多次尝试，没能实现多线程迁移数据，希望有高手指点。谢谢！

 

public class ConcurrentTestPreparedStmt
{

    public static int     totalRowNum;

    public static int     index = 1;

    public static boolean isFinish;

    public static void main(String[] args) throws Exception
    {
        Class.forName("oracle.jdbc.driver.OracleDriver");

        String url = "jdbc:oracle:thin:@192.168.5.201:1521:orcl";
        String user = "scott";
        String password = "tiger";

        String sql = "select * from dept";

        Connection conn = DriverManager.getConnection(url, user, password);

        /**
         * 读取
         */
        Statement stmt = conn.createStatement(
            ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
        ResultSet rs = stmt.executeQuery(sql);

        /**
         * 写入
         * 使用批处理
         */
        PreparedStatement pstmt = null;
        String psql = "insert into testpstmt values(?,?,?)";
        pstmt = conn.prepareStatement(psql);
        //rs.next 只要为true，说明表中记录数

        rs.last();
        totalRowNum = rs.getRow();

        int i = 0;
        //问题所在，当 i<2时，表示两个线程，执行时，往目的表中插入了同样一行记录。
        while (i < 1 && !isFinish)
        {
            TaskThread t = new ConcurrentTestPreparedStmt().new TaskThread(
                pstmt, rs);
            new Thread(t).start();
            i++;
        }

        //如果没完成，则主线程等待
        while (!isFinish)
        {
            Thread.sleep(500);
        }
        pstmt.executeBatch();
        conn.commit();

        System.out.println("SUCCESS");

    }

    public synchronized int incrementIndex()
    {
        return index++;
    }

    public synchronized int getExecuteNum()
    {
        return index;
    }

    /**
     * 并发迁移类
     * @author ttan
     */
    class TaskThread implements Runnable
    {
        PreparedStatement pstmt = null;
        ResultSet         rs    = null;

        public TaskThread(PreparedStatement pstmt, ResultSet rs)
        {
            this.rs = rs;
            this.pstmt = pstmt;
        }

        @Override
        public void run()
        {

            int index = incrementIndex();
            //指定到具体的行数
            try
            {
                while (index <= totalRowNum)
                {
                    System.out.println("index = " + index);
                    rs.absolute(index);
                    pstmt.setInt(1, rs.getInt(1));
                    pstmt.setString(2, rs.getString(2));
                    pstmt.setString(3, rs.getString(3));

                    pstmt.addBatch();

                    index = incrementIndex();
                }

                if (getExecuteNum() > totalRowNum)
                {
                    isFinish = true;
                    return;
                }

            }
            catch (SQLException e)
            {
                e.printStackTrace();
            }
        }
    }
}

 

转自：http://bbs.csdn.net/topics/390456469