JDBC Template Connection

Package itcast;

Import java.sql.Connection;
Import Java.sql.DriverManager;
Import Java.sql.ResultSet;
Import java.sql.SQLException;
Import java.sql.Statement;

public class Base {

/**
* @param args
*/
public static void Main (string[] args) {

}

static void Template () throws Exception {
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
2 Creating Links
Jdbcutils.getconnection ();
3 Creating statements
st = Conn.createstatement ();
4 EXECUTE statement
rs = St.executequery ("SELECT * from user");
5 Processing results
while (Rs.next ()) {
System.out.println (Rs.getobject (1) + "T" + rs.getobject (2)
+ "\ T" + rs.getobject (3) + "\ T" + rs.getobject (4)
+ "\ T" + rs.getobject (5) + "\ T");
}
} finally {
Jdbcutils.free (RS, St, conn);
}
}

}

Simple Method *********************************************************************

Package itcast;

Import java.sql.Connection;
Import Java.sql.DriverManager;
Import Java.sql.ResultSet;
Import java.sql.SQLException;
Import java.sql.Statement;

Public final class Jdbcutils {
private static String URL = "Jdbc:mysql://localhost:3306/test";
private static String user = "root";
private static String password = "";

Private method of construction
Private Jdbcutils () {
}

Put the registration-driven action inside the static code block
static {
try {
Class.forName ("Com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
E.printstacktrace ();
throw new Exceptionininitializererror (e);
}
}

Establish links
public static Connection getconnection () throws SQLException {
Return drivermanager.getconnection (URL, user, password);
}

Freeing resources
public static void Free (ResultSet rs, Statement St, Connection conn) {
try {
if (rs! = null) {
Rs.close ();
}
} catch (SQLException e) {
E.printstacktrace ();
} finally {
try {
if (st! = null) {
St.close ();
}
} catch (SQLException e) {
E.printstacktrace ();
} finally {
try {
IF (conn! = null) {
Conn.close ();
}
} catch (SQLException e) {
E.printstacktrace ();
}
}
}
}
}

Single case method trouble not recommended **************************************************

Package CN.ITCAST.JDBC;

Import java.sql.Connection;
Import Java.sql.DriverManager;
Import Java.sql.ResultSet;
Import java.sql.SQLException;
Import java.sql.Statement;

Public final class Jdbcutilssing {
Private String URL = "Jdbc:mysql://localhost:3306/test";
Private String user = "root";
Private String Password = "";

private static Jdbcutilssing instance = new Jdbcutilssing ();
private static jdbcutilssing instance = NULL;
Private method of construction
Private jdbcutilssing () {
}

public static jdbcutilssing getinstance () {
if (instance = = null) {
Synchronized (Jdbcutilssing.class) {
if (instance = = null) {
Instance = new Jdbcutilssing ();
}
}
}
return instance;
}

Put the registration-driven action inside the static code block
static {
try {
Class.forName ("Com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
E.printstacktrace ();
throw new Exceptionininitializererror (e);
}
}

Establish links
Public Connection getconnection () throws SQLException {
Return drivermanager.getconnection (URL, user, password);
}

Freeing resources
public void Free (ResultSet rs, Statement St, Connection conn) {
try {
if (rs! = null) {
Rs.close ();
}
} catch (SQLException e) {
E.printstacktrace ();
} finally {
try {
if (st! = null) {
St.close ();
}
} catch (SQLException e) {
E.printstacktrace ();
} finally {
try {
IF (conn! = null) {
Conn.close ();
}
} catch (SQLException e) {
E.printstacktrace ();
}
}
}
}
}