mysql分库模板

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

public class ShardingExample {
    private static final String DB_URL_1 = "jdbc:mysql://localhost:3306/db1";
    private static final String DB_URL_2 = "jdbc:mysql://localhost:3306/db2";
    private static final String USER = "user";
    private static final String PASS = "password";

    public static void main(String[] args) {
        int userId = 123; // 假设用户ID为123
        String dbUrl = userId % 2 == 0 ? DB_URL_1 : DB_URL_2;

        try (Connection conn = DriverManager.getConnection(dbUrl, USER, PASS)) {
            String sql = "SELECT * FROM users WHERE id = ?";
            try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
                pstmt.setInt(1, userId);
                try (ResultSet rs = pstmt.executeQuery()) {
                    while (rs.next()) {
                        System.out.println("User ID: " + rs.getInt("id") + ", Name: " + rs.getString("name"));
                    }
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}