获取java.sql.SQLException: - ORA-01000:DML超出最大打开游标数(更新语句)

Question

我正在读取包含30000行的excel文件,并尝试根据某些逻辑更新Oracle dB表字段.我的Java应用程序错误输出"java.sql.SQLException: - ORA-01000:超出最大打开游标数",当它在表中写入大约700条记录时.需要帮助优化代码以避免此错误.

import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.ResourceBundle;

import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import oracle.jdbc.driver.OracleDriver;

public class UpdateTest {
    private static Connection conn = null;
    static ResourceBundle bundle = ResourceBundle.getBundle("PropertiesFile");
    public static void main(String[] args) {

    String filename = bundle.getString("FILEPATH") + bundle.getString("FILENAME");
    FileInputStream fileInputStream = null;
    String input = null;
    PreparedStatement preparedStatement = null;
    Integer result = null;
    int counter = 0;

    try {
        DriverManager.registerDriver(new OracleDriver());
        conn = DriverManager.getConnection(
                bundle.getString("DATABASE_URL"), 
                bundle.getString("DATABASE_USERNAME"),
                bundle.getString("DATABASE_PASSWORD"));
        conn.setAutoCommit(false);

        fileInputStream = new FileInputStream(filename);
        XSSFWorkbook workbook = new XSSFWorkbook(fileInputStream);
        XSSFSheet sheet = workbook.getSheetAt(0);
        System.out.println("Number of records to be updated: " + (sheet.getPhysicalNumberOfRows() - 1));

        Iterator i = sheet.iterator();
        while (i.hasNext()) {
            XSSFRow row = (XSSFRow) i.next();
            input = row.getCell(0).toString();
            preparedStatement = conn.prepareStatement("update table1 set column1='value' where input=?");
            preparedStatement.setString(1, input);
            result = preparedStatement.executeUpdate();
        }

        if (preparedStatement != null) {
            preparedStatement.close();
        }
        conn.commit();
        conn.close();

    } catch (Exception e) {
        if (conn != null) {
            try {
                conn.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
        }
        e.printStackTrace();
    } finally {
        try {
            if (conn != null && !conn.isClosed()) {
                if (!conn.getAutoCommit()) {
                    conn.commit();
                    conn.setAutoCommit(true);
                }
                conn.close();
                conn = null;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

}

}

Answer 1

每次调用prepareStatement()都会在Oracle服务器中创建一个未在循环中关闭的新游标.

避免"太多打开游标"的正确解决方案是仅通过在循环之前仅准备一次语句来创建一个游标.

preparedStatement = conn.prepareStatement("update table1 set column1='value' where input=?");

Iterator i = sheet.iterator();
while (i.hasNext()) {
    XSSFRow row = (XSSFRow) i.next();
    input = row.getCell(0).toString();
    preparedStatement.setString(1, input);
    result = preparedStatement.executeUpdate();
 }

然后在finally块中循环后关闭它.

prepareStatement()循环调用会破坏PreparedStatement的目的和意图.