JDBC obtains metadata DatabaseMetaData, databasemetadata

JDBC obtains metadata DatabaseMetaData, databasemetadata

Package org. data. jdbc; import java. SQL. connection; import java. SQL. databaseMetaData; import java. SQL. driverManager; import java. SQL. preparedStatement; import java. SQL. resultSet; import java. SQL. resultSetMetaData; import java. SQL. SQLException; public class Jdbc {// database connection address private static final String url = "jdbc: mysql: // localhost: 3306/data "; // username and password private static final String user = "root"; private static final Str Ing pwd = "123456";/***** database query * @ throws ClassNotFoundException */public static void query () throws ClassNotFoundException {Connection conn = null; java. SQL. preparedStatement pst = null; ResultSet re = null;/** DBC provides DatabaseMetaData to encapsulate the database information corresponding to the database Connection, and obtains the object through the getMetaData method of the Connection. * The DatabaseMetaData interface is usually implemented by the database driver provider to help users understand the underlying information of the database. * You can use this interface to understand the underlying implementation of the database and switch between multiple databases. */DatabaseMetaData metadata = null; try {Class. forName ("com. mysql. jdbc. driver "); conn = DriverManager. getConnection (url, user, pwd); metadata = conn. getMetaData (); System. out. println ("known database users:" + metadata. getUserName (); System. out. println ("comma-separated list of database system functions:" + metadata. getSystemFunctions (); System. out. println ("comma-separated list of database time and date functions:" + metadata. getTimeDateFunctions (); System. out. println ("comma-separated list of database string functions: "+ Metadata. getStringFunctions (); System. out. println ("the preferred term for database providers for 'schema':" + metadata. getSchemaTerm (); System. out. println ("Database URL:" + metadata. getURL (); System. out. println ("allow read-only:" + metadata. isReadOnly (); System. out. println ("database product name:" + metadata. getDatabaseProductName (); System. out. println ("database version:" + metadata. getDatabaseProductVersion (); System. out. println ("driver name:" + metadata. g EtDriverName (); System. out. println ("driver version:" + metadata. getDriverVersion (); System. out. println ("driver version:" + metadata. getTableTypes (); System. out. println ("..................................... ....... "); pst = conn. prepareStatement ("select * from customerinfo"); // obtain the database column recyclpst.exe cuteQuery (); // The database column name ResultSetMetaData data = re. getMetaData (); // getColumnCount obtains the number of table columns for (int I = 1; I <= data. getColumnC Ount (); I ++) {// obtain the Data Length of the List index starting from 1, column name, column type, and column. System. out. println (data. getColumnName (I) + "\ t" + data. getColumnTypeName (I) + "\ t" + data. getColumnDisplaySize (I);} catch (SQLException e) {e. printStackTrace () ;}finally {closeConnection (conn, pst, re );}} /*** close the database link * @ param conn * @ param pst * @ param re */public static void closeConnection (Connection conn, PreparedStatement pst, ResultSet re) {if (conn! = Null) try {conn. close ();} catch (SQLException e) {// TODO Auto-generated catch blocke. printStackTrace ();} if (pst! = Null) try {pst. close ();} catch (SQLException e) {// TODO Auto-generated catch blocke. printStackTrace ();} if (re! = Null) try {re. close ();} catch (SQLException e) {// TODO Auto-generated catch blocke. printStackTrace () ;}} public static void main (String [] args) {try {query ();} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke. printStackTrace ();}}}