Get JDBC Connection singleton mode

package base;import java.sql.connection;import java.sql.drivermanager;import  java.sql.resultset;import java.sql.sqlexception;import java.sql.statement;//tool classes that cannot be inherited public  final class jdbcutilssingleton {//the privatization of member variables to prevent the other classes from affecting the common variables private  string url =   "JDBC:MYSQL://127.0.0.1:3306/JDBC";p rivate  string username =  "root";p rivate   String password =  "123456";p rivate static jdbcutilssingleton  instance=null;//privatisation constructors to ensure that the Private jdbcutilssingleton () is not instantiated externally {}/** *  take into account the concurrency needs of the yoke  * @ Return */public static jdbcutilssingleton getinstance () {if (instance == null) { Synchronized (Jdbcutilssingleton.class) {if (instance == null) {instance = new  Jdbcutilssingleton ();}}} Return instance;} Only one connection static{try {class.forname ("Com.mysql.jdbc.Driver") is created when the JVM is loaded;}  catch  (Classnotfoundexception e)  {// todo auto-generated catch blocke.printstacktrace ();}} Get Connection public connection getconnection ()  throws SQLException{return  Drivermanager.getconnection (Url, username, password);} Canonical Release resource method Public void free (Resultset rs,statement stmt,connection conn) {try{if (RS  != null) Rs.close ();} catch (sqlexception e) {e.printstacktrace ();} Finally{try{if (Stmt != null) Stmt.close ();} catch (Sqlexception ex) {ex.printstacktrace ();} Finally{try{if (Conn != null) Conn.close ();} catch (Sqlexception em) {em.printstacktrace ();}}}}}

Summary of the main points of the single case model:

1. Privatization instance class variables and constructors ensure that the object is not instantiated externally, guaranteeing a unique singleton.

2. Take into account that the program concurrent processing needs to lock

3. Obtaining an instance through a unique entry static method: GetInstance ()

This article is from the "Love Coffee" blog, please be sure to keep this source http://4837471.blog.51cto.com/4827471/1589424

Get JDBC Connection singleton mode