使用JDBC和Postgres将未知数量的参数传递给IN子句

import java.sql.*;

public class JDBCExample {
    public static void main(String[] args) {
        String url = "jdbc:postgresql://localhost:5432/mydatabase";
        String username = "myusername";
        String password = "mypassword";

        try (Connection conn = DriverManager.getConnection(url, username, password)) {
            String sql = "SELECT * FROM mytable WHERE id IN (";
            int numParams = 5; // 假设有5个参数

            // 构建IN子句
            StringBuilder inClause = new StringBuilder();
            for (int i = 0; i < numParams; i++) {
                inClause.append("?");
                if (i < numParams - 1) {
                    inClause.append(",");
                }
            }
            sql += inClause.toString() + ")";

            // 创建PreparedStatement对象
            PreparedStatement pstmt = conn.prepareStatement(sql);

            // 设置参数值
            for (int i = 1; i <= numParams; i++) {
                pstmt.setInt(i, i); // 假设参数值为1, 2, 3, 4, 5
            }

            // 执行查询操作
            ResultSet rs = pstmt.executeQuery();

            // 处理查询结果
            while (rs.next()) {
                // 处理每一行数据
                int id = rs.getInt("id");
                String name = rs.getString("name");
                // 其他列的处理...
                System.out.println("ID: " + id + ", Name: " + name);
            }

            // 关闭资源
            rs.close();
            pstmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}