如何从jdbc中获取数据库建表语句信息(表字段名称/表字段类型/表字段注释信息/表字段长度等等)

package com.yangcq.learning.hantang.learning;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import lombok.extern.slf4j.Slf4j;
import java.sql.*;
/**
* 如何从jdbc中获取数据库建表语句信息(表字段名称/表字段类型/表字段注释信息/表字段长度等等)
* 1，表字段名称
* 2，表字段类型
* 3，表字段注释信息
*/
@Slf4j
public class How2ObtainFieldInfoFromJdbc {
private static Connection connection;
public static void main(String[] args) {
How2ObtainFieldInfoFromJdbc how2ObtainFieldInfoFromJdbc = new How2ObtainFieldInfoFromJdbc();
// 第一种方式：执行sql语句获取 select * from user_pop_info where 1 = 2
how2ObtainFieldInfoFromJdbc.method1();
// 第二种方式：执行sql语句获取 show create table user_pop_info
how2ObtainFieldInfoFromJdbc.method2();
// 第二种方式：直接从jdbc数据库连接Connection实例中获取
how2ObtainFieldInfoFromJdbc.method3();
}
private void method1() {
try{
PreparedStatement preparedStatement = connection.prepareStatement("select * from user_pop_info where 1 = 2");
ResultSetMetaData resultSetMetaData = preparedStatement.executeQuery().getMetaData();
for (int i = 0; i < resultSetMetaData.getColumnCount(); i++) {
log.info("数据库实例名:{}", resultSetMetaData.getCatalogName(i + 1));
log.info("表名:{}", resultSetMetaData.getTableName(i + 1));
log.info("java类型:{}", resultSetMetaData.getColumnClassName(i + 1));
log.info("数据库类型:{}", 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 user_pop_info");
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, "%", "user_pop_info", "%");
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{
// 数据源配置
DataSourceConfig dataSourceConfig = new DataSourceConfig();
dataSourceConfig.setUrl("jdbc:mysql://127.0.0.1:3306/databasename?serverTimezone=GMT%2b8&Unicode=true&characterEncoding=utf8");
dataSourceConfig.setDriverName("com.mysql.jdbc.Driver");
dataSourceConfig.setUsername("root");
dataSourceConfig.setPassword("1234567");
connection = dataSourceConfig.getConn();
} catch (Exception e) {
log.error("autoCodeGeneratorProcess error ", e);
}
}
}