java - 批处理 JDBC

Question

我正在练习 JDBC 批处理并遇到错误:

错误1:不支持的功能错误2:执行不能为空或为null

Property files include:
itemsdao.updateBookName = Update Books set bookname = ? where books.id = ?
itemsdao.updateAuthorName = Update books set authorname = ? where books.id = ?

我知道我可以在一次更新中执行 DML 语句，但我正在练习 JDBC 中的批处理。

下面是我的方法

public void update(Item item) {
            String query = null;

        try {
            connection = DbConnector.getConnection();
            property = SqlPropertiesLoader.getProperties("dml.properties");
            connection.setAutoCommit(false);

            if ( property == null )
            {
                Logging.log.debug("dml.properties does not exist. Check property loader or file name is spelled right");
                return;
            }

            query = property.getProperty("itemsdao.updateBookName");
            statement = connection.prepareStatement(query);
            statement.setString(1, item.getBookName());
            statement.setInt(2, item.getId());
            statement.addBatch(query);

            query = property.getProperty("itemsdao.updateAuthorName");
            statement = connection.prepareStatement(query);
            statement.setString(1, item.getAuthorName());
            statement.setInt(2, item.getId());
            statement.addBatch(query);

            statement.executeBatch();
            connection.commit();

        }catch (ClassNotFoundException e) {
            Logging.log.error("Connection class does not exist", e);
        } 
        catch (SQLException e) {
            Logging.log.error("Violating PK constraint",e);
        }

        //helper class th
        finally {

            DbUtil.close(connection);
            DbUtil.closePreparedStatement(statement);

        }

Answer 1

您正在将 Statement 的方法混合在一起和 PreparedStatement类(class):

• (addBatch(String sql) 属于 Statement，不能在 PreparedStatement 或 上调用CallableStatement

• addBatch() 与 PreparedStatement 一起使用(如教程所示)。

Oracle 实现了它自己的批处理和标准批处理 (JDBC 2.0)。来自 Standard Update Batching docs :

In Oracle JDBC applications, update batching is intended for use with prepared statements that are being processed repeatedly with different sets of bind values.