Java APIs for database------JDBC

# JDBC
# Study Note of JAVA Tutorial
# Victor
# 2016.05.27

JDBC helps-write Java applications that manage these three programming activities:

1. Connect to a data source, like a database
2. End queries and UPDATE statements to the database
3. Etrieve and process the results received from the database in answer to your query

 PackageMyjdbc;Importjava.sql.Connection;ImportJava.sql.DriverManager;Importjava.sql.PreparedStatement;ImportJava.sql.ResultSet;ImportJava.sql.ResultSetMetaData;Importjava.sql.SQLException;//Connect to Oracle database Public classdbsession {PrivateConnection con =NULL; PrivatePreparedStatement pstmt =NULL; PrivateString Dburl =NULL; PrivateString username =NULL; PrivateString Password =NULL;  Publicdbsession (String url,string user,string pass) {Dburl=URL; Username=user; Password=Pass; }        Private Booleangetdbconnection () {Try {                //initializing the driver packageClass.forName ("Oracle.jdbc.driver.OracleDriver"); //assign a value to connection based on the database connection character, name, and passwordCon =drivermanager.getconnection (dburl, username, password); return true; } Catch(Exception e) {e.printstacktrace (); Setis_exception (true);        Setex (e); return false; }    }        Private Booleangetpreparestatement (String sql) {Try {            //working with SQL statementsPSTMT =con.preparestatement (SQL); return true; } Catch(SQLException e) {e.printstacktrace (); Setis_exception (true);            Setex (e); return false; }    }         Public voidexecute (String sql) {if(Getdbconnection ()) {SQL=sql.touppercase (); System.out.println ("Execute SQL::" +SQL); if(getpreparestatement (SQL)) {if(Sql.startswith ("select")){                    Try{ResultSet res=Pstmt.executequery (); Setis_select (true);                    Setresultset (RES); } Catch(SQLException e) {//TODO auto-generated Catch blockE.printstacktrace (); Setis_exception (true);                    Setex (e); }                }                Else if(Sql.startswith ("INSERT") | | sql.startswith ("UPDATE") | | sql.startswith ("DELETE"))){                    Try{Integer count=pstmt.executeupdate (); Setis_update (true);                    SetCount (count); } Catch(SQLException e) {//TODO auto-generated Catch blockE.printstacktrace (); Setis_exception (true);                    Setex (e); }                }                Else{setis_exception (true); Setex (NewException ("Other functions is not supported in class Dbsession")); }            }            Else{System.out.println ("Prepare SQL statement exception!"); }        }        Else{System.out.println ("Connect Oracle Database exception!"); }    }         Public voidprintexception () {System.out.println ("Dbsession::" +GetEx ()); }         Public voidPrintresult ()throwssqlexception{if(Isis_update ()) {System.out.println ("Update Database:" +getcount () + "Rows"); } Else if(Isis_select ()) {ResultSetMetaData Rsmd=Resultset.getmetadata (); intColumnsnumber =Rsmd.getcolumncount (); intRowNumber =0; //Traverse ResultSet             while(Resultset.next ()) {RowNumber++;  for(inti = 1;i <= columnsnumber;i++) {System.out.println ("Row->" +rownumber+ ", column->" +i+ ", Selected value is:" +resultset.getstring (i)); }            }        }    }        Private BooleanIs_exception =false; Private BooleanIs_update =false; Private BooleanIs_select =false; PrivateException ex =NULL; PrivateInteger count =NULL; PrivateResultSet ResultSet =NULL;  Public Booleanis_exception_occured () {returnis_exception; }    Private voidSetis_exception (Booleanis_exception) {         This. is_exception =is_exception; }     Public Booleanisis_update () {returnis_update; }    Private voidSetis_update (Booleanis_update) {         This. is_update =is_update; }     Public BooleanIsis_select () {returnIs_select; }    Private voidSetis_select (Booleanis_select) {         This. Is_select =Is_select; }     PublicException GetEx () {returnex; }    Private voidSetex (Exception ex) { This. ex =ex; }     PublicInteger GetCount () {returncount; }    Private voidSetCount (Integer count) { This. Count =count; }     PublicResultSet Getresultset () {returnresultset; }    Private voidSetresultset (ResultSet ResultSet) { This. ResultSet =resultset; }         Public voidClose () {Try {            if(!(resultset.isclosed ()))            {Resultset.close (); }            if(!(pstmt.isclosed ()))            {Pstmt.close (); }            if(!(con.isclosed ()))            {Con.close (); } System.out.println ("Session Close successfully!"); } Catch(SQLException e) {//TODO auto-generated Catch blockE.printstacktrace (); }    }}

View Code

TEST CODE:

 PackageMyjdbc;Importjava.sql.SQLException; Public classJdbc_test { Public Static voidMain (string[] args)throwsSQLException {//TODO auto-generated Method StubDbsession db =NewDbsession ("Jdbc:oracle:thin: @localhost: 1522/xe", "Victor", "123"); Db.execute ("Select Sysdate from Dual"); if(db.is_exception_occured ()) {db.printexception (); }        Else{db.printresult ();    } db.close (); }}

View Code

OUTPUT:

Execute SQL:: SELECT sysdate from DUAL
Row->1, Column->1, selected value is:2016-05-27 17:16:03.0
Session Close successfully!

Java APIs for database------JDBC