java 分批读取mysql数据库表程序

以下是Java读取MySQL数据库表的分批处理程序示例：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class BatchReadMySQLTable {

    private static final String URL = "jdbc:mysql://localhost:3306/test";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "password";
    private static final int BATCH_SIZE = 1000; //每批处理的记录数

    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;

        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);

            //查询总记录数
            stmt = conn.prepareStatement("SELECT COUNT(*) FROM my_table");
            rs = stmt.executeQuery();
            rs.next();
            int totalRecords = rs.getInt(1);

            //分批读取数据
            int processedRecords = 0;
            while (processedRecords < totalRecords) {
                stmt = conn.prepareStatement("SELECT * FROM my_table LIMIT ?, ?");
                stmt.setInt(1, processedRecords);
                stmt.setInt(2, BATCH_SIZE);
                rs = stmt.executeQuery();

                while (rs.next()) {
                    //处理每一行记录
                    //TODO: 你的处理逻辑
                }

                processedRecords += BATCH_SIZE;
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

该程序首先查询数据库表的总记录数，然后通过循环分批读取数据，每次读取 BATCH_SIZE 条记录。在读取每一行记录时，你可以编写自己的处理逻辑。注意，程序中的 "my_table" 应该替换为实际的表名。