三种方式从jdbc中获取数据库表字段信息

一、整体代码

1、method1：执行select语句获取，select * from dims where 1 = 2

2、method2：执行show create table获取，show create table dims

3、method3：从jdbc数据库连接获取

import lombok.extern.slf4j.Slf4j;

import java.sql.*;
import java.util.Properties;

/**
 * 从jdbc中获取数据库表字段信息(包含字段名称、字段类型、字段注释、字段长度等)
 */
@Slf4j
public class test {
    private static Connection connection;

    public static void main(String[] args) {
        test test = new test();
        // 第一种方式：执行sql语句获取 select * from dims where 1 = 2
        test.method1();
        // 第二种方式：执行sql语句获取 show create table dims
        test.method2();
        // 第三种方式：直接从jdbc数据库连接Connection实例中获取
        test.method3();
    }

    private void method1() {
        try{
            PreparedStatement preparedStatement = connection.prepareStatement("select * from dims where 1 = 2");
            ResultSetMetaData resultSetMetaData = preparedStatement.executeQuery().getMetaData();
            for (int i = 0; i < resultSetMetaData.getColumnCount(); i++) {
                log.info("实例名:{}", resultSetMetaData.getCatalogName(i + 1));
                log.info("表名:{}", resultSetMetaData.getTableName(i + 1));
                log.info("类型:{}", resultSetMetaData.getColumnClassName(i + 1));
                log.info("列类型:{}", resultSetMetaData.getColumnTypeName(i + 1));
                log.info("字段名称:{}", resultSetMetaData.getColumnName(i + 1));
                log.info("字段长度:{}", resultSetMetaData.getColumnDisplaySize(i + 1));
                log.info("getColumnType:{}", resultSetMetaData.getColumnType(i + 1));
                log.info("getPrecision:{}", resultSetMetaData.getPrecision(i + 1));
                log.info("getScale:{}", resultSetMetaData.getScale(i + 1));
                log.info("getSchemaName:{}", resultSetMetaData.getSchemaName(i + 1));
                log.info("getScale:{}", resultSetMetaData.getScale(i + 1));
            }
        } catch (Exception e) {
            log.error("method1 error ", e);
        }
    }

    private void method2() {
        try{
            PreparedStatement preparedStatement2 = connection.prepareStatement("show create table dims");
            ResultSet resultSet2 = preparedStatement2.executeQuery();
            while(resultSet2.next()) {
                String tableName = resultSet2.getString("Table");
                String createTable = resultSet2.getString("Create Table");
                log.info("tableName:{}", tableName);
                log.info("createTable:");
                System.out.println(createTable);
            }
        } catch (Exception e) {
            log.error("method2 error ", e);
        }
    }

    private void method3() {
        try{
            DatabaseMetaData databaseMetaData = connection.getMetaData();
            // 获取所有表
            ResultSet resultSet = databaseMetaData.getTables(null, null, null, new String[]{"TABLE"});
            // 获取指定表
            ResultSet specificResultSet = databaseMetaData.getColumns(null, "%", "dims", "%");
            String columnName2;
            String columnType2;
            String comment2;
            while(specificResultSet.next()) {
                columnName2 = specificResultSet.getString("COLUMN_NAME");
                columnType2 = specificResultSet.getString("TYPE_NAME");
                comment2 = specificResultSet.getString("REMARKS");
                log.info("COLUMN_NAME:{}", columnName2);
                log.info("TYPE_NAME:{}", columnType2);
                log.info("REMARKS:{}", comment2);
            }
        } catch (Exception e) {
            log.error("method3 error ", e);
        }
    }

    static {
        try{
            Properties info = new Properties(); // 定义Properties对象
            info.setProperty("user", "user"); // 设置Properties对象属性
            info.setProperty("password", "123456");
            Class.forName("com.mysql.cj.jdbc.Driver"); // 注册数据库驱动
            String url = "jdbc:mysql://127.0.0.1:3306/databases"; // briup为数据库名称
            connection = DriverManager.getConnection(url, info); // 获取连接数据库的Connection对象
        } catch (Exception e) {
            log.error("autoCodeGeneratorProcess error ", e);
        }
    }
}