Java 获取Mysql数据库表的列

public class GetTableSchema {
    private static final String DRIVER = "com.mysql.jdbc.Driver";

    private static final String URL = "jdbc:mysql://localhost:3306/loctest";

    private static final String USERNAME = "root";

    private static final String PASSWORD = "***";

    public static void main(String[] args) throws Exception {
        Class.forName(DRIVER);
        Connection connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);

        DatabaseMetaData metadata = connection.getMetaData();
        ResultSet resultSet = metadata.getColumns(null, null, "loctest.user", null);
        
        while (resultSet.next()) {
            String name = resultSet.getString("COLUMN_NAME");
            String type = resultSet.getString("TYPE_NAME");
            int size = resultSet.getInt("COLUMN_SIZE");

            System.out.println("Column name: [" + name + "]; type: [" + type + "]; size: [" + size + "]");
        }
        connection.close();
    }
}

　在项目中，需要将爬虫获取的非结构化json数据解析拉平放入关系数据库中，为了防止插入失败，需要比较表中列和插入的列，只插入数据库中有的列，没有的列邮件提醒，下次修改数据库表结构之后进行插入。