When connecting to SQL using Java, obtain the attributes of each column in the table

Import java. SQL. connection;
Import java. SQL. drivermanager;
Import java. SQL. resultset;
Import java. SQL. preparedstatement;
Import java. SQL. resultsetmetadata;
Import java. SQL. sqlexception;

Public class testdemo {
Public static connection getconnection (){
Connection conn = NULL;
Try {
Class. forname ("com. MySQL. JDBC. Driver ");
String url = "JDBC: mysql: // localhost: 3306/struts2demo ";
String user = "root ";
String pass = "123456 ";
Conn = drivermanager. getconnection (URL, user, pass );
} Catch (classnotfoundexception e ){
E. printstacktrace ();
} Catch (sqlexception e ){
E. printstacktrace ();
}
Return conn;
}
Public static void main (string [] ARGs ){
Connection conn = getconnection ();
String SQL = "select * from users ";
Preparedstatement stmt;
Try {
Stmt = conn. preparestatement (SQL );
Resultset rs1_stmt.exe cutequery (SQL );
Resultsetmetadata DATA = Rs. getmetadata ();
While (Rs. Next ()){
For (INT I = 1; I <= data. getcolumncount (); I ++ ){
// Obtain the number of all columns and the actual number of Columns
Int columncount = data. getcolumncount ();
// Obtain the name of the specified Column
String columnname = data. getcolumnname (I );
// Obtain the column value of the specified Column
String columnvalue = Rs. getstring (I );
// Obtain the data type of the specified Column
Int columntype = data. getcolumntype (I );
// Obtain the data type name of the specified Column
String columntypename = data. getcolumntypename (I );
// The Catalog name
String catalogname = data. getcatalogname (I );
// Corresponding data type class
String columnclassname = data. getcolumnclassname (I );
// Maximum number of characters in the database
Int columndisplaysize = data. getcolumndisplaysize (I );
// Default Column Title
String columnlabel = data. getcolumnlabel (I );
// Obtain the column Mode
String schemaname = data. getschemaname (I );
// Precision of a column type (type length)
Int precision = data. getprecision (I );
// Number of digits after the decimal point
Int scale = data. getscale (I );
// Obtain the table name corresponding to a column
String tablename = data. gettablename (I );
// Auto Increment
Boolean isautoinctement = data. isautoincrement (I );
// Whether it is a currency type in the database
Boolean iscurrency = data. iscurrency (I );
// Whether it is null
Int isnullable = data. isnullable (I );
// Whether it is read-only
Boolean isreadonly = data. isreadonly (I );
// Whether it can appear in where
Boolean issearchable = data. issearchable (I );
System. Out. println (columncount );
System. Out. println ("Get column" + I + "field name:" + columnname );
System. Out. println ("Get column" + I + "field value:" + columnvalue );
System. Out. println ("retrieve column" + I + "type, return number in sqltype:" + columntype );
System. Out. println ("Get column" + I + "data type name:" + columntypename );
System. Out. println ("retrieve column" + I + "catalog name:" + catalogname );
System. Out. println ("Get column" + I + ":" + columnclassname );
System. Out. println ("Get column" + I + "Maximum number of characters in the Database Type:" + columndisplaysize );
System. Out. println ("Get column" + I + "Default column title:" + columnlabel );
System. Out. println ("Get column" + I + "Mode:" + schemaname );
System. Out. println ("Get column" + I + "type precision (type length):" + precision );
System. Out. println ("Get column" + I + "digits after decimal point:" + scale );
System. Out. println ("Get column" + I + "corresponding table name:" + tablename );
System. Out. println ("Get column" + I + "auto increment:" + isautoinctement );
System. Out. println ("retrieve columns" + I + "in the database for currency type:" + iscurrency );
System. Out. println ("Get column" + I + "blank:" + isnullable );
System. Out. println ("Get column" + I + "read-only:" + isreadonly );
System. Out. println ("retrieve column" + I + "can appear in where:" + issearchable );
}
}
} Catch (sqlexception e ){
System. Out. println ("database connection failed ");
}
}
}