comparison, application and summary of single-case models

Related Excellent article: http://blog.csdn.net/beyond0525/article/details/22794221

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Http://www.blogjava.net/ITdavid/archive/2008/01/22/176939.html

Http://www.cnblogs.com/yidianfeng/archive/2011/11/07/2239246.html

http://spiritfrog.iteye.com/blog/214986

Code Change comparison:

Singleton mode public class DAO {private static dao DAO = null;private Context context;private dao (Context contex) {This.context = Contex;} public static DAO getinstance (context context) {if (dao = = null) {DAO = new dao (Context.getapplicationcontext ());} return DAO;} Connection Database public Sqlitedatabase getconnection () {sqlitedatabase sqlitedatabase = null;try {sqlitedatabase = new DatabaseHel Per (context, databasehelper.dbname). Getreadabledatabase ();} catch (Exception e) {e.printstacktrace ();} return sqlitedatabase;} public static void CreateTable (Sqlitedatabase sqlitedatabase) {sqlitedatabase.execsql ("CREATE TABLE IF not EXISTS Priasetable (ID integer primary key autoincrement,clickid varchar), "+" clicktype varchar (+), Clickcount Integer, Nativeclick INTEGER) ");} public static void Createrecordtable (Sqlitedatabase sqlitedatabase) {sqlitedatabase.execsql ("CREATE TABLE IF not EXISTS Playrecordtable (ID integer PRIMARY key autoincrement,playid varchar (+), "+" playtype varchar (+), path varchar (100), ADPath VARchar (+), APIC varchar (+), Shareurl varchar (+), Title varchar (+), time varchar (100)); /** * Create upload server table uploadtable * mid-type STREAM-FTP file address on server uid-upload user ID * */public static void creatuploadtable (Sqlitedatabase s Qlitedatabase) {sqlitedatabase.execsql ("CREATE TABLE IF not EXISTS uploadtable (ID integer PRIMARY key autoincrement" + ", UID varchar (+), mid varchar (+), Title varchar (+), description varchar (255) "+", stream varchar (+), Time varchar ( 100)) ");} @SuppressLint ("SimpleDateFormat") public synchronized void insertuploadtable (Ftploadinfo ftploadinfo) { Sqlitedatabase database = getconnection (); try {String sql = "INSERT INTO uploadtable (" + "UID, Mid, title, description, str Eam,time) VALUES (?,?,?,?,?,?) ";D Ate date = new Date (); SimpleDateFormat SimpleDateFormat = new SimpleDateFormat (); String time = Simpledateformat.format (date); object[] info = {Ftploadinfo.getuid (), Ftploadinfo.getmid (), Ftploadinfo.getname (), Ftploadinfo.getdesc (), Ftploadinfo.getstream (), Time};d atabase.execsql (sql, info);}catch (Exception e) {e.printstacktrace ();} finally {if (null! = database) {database.close ();}}} 

Post-Change Code:

Singleton mode 5 mode, recommended static internal use of the public class Dao {//context used to connect the database private static context context;//database library Manager private static Databasehelper mdatebasehelper;//Database private static sqlitedatabase mdatabase;/** * Inner class implementation Singleton mode * Deferred load, reduced memory overhead * Method Singleto N has a static inner class Singletonholder, the inner class does not load when it is loaded externally, and is not loaded until the call getinstance. * In addition, the Singletonholder class uses private adornments to ensure that external classes are inaccessible. * Pros: Lazy loading, thread safety (mutually exclusive during class loading in Java), also reduced memory consumption */private static class Daoholder{private static DAO DAO = new Dao ();} /** * Private Constructor * Deferred initialization */Private Dao () {//Lazy initialization Global context, initializing connection database eliminates each call method to connect server Mdatebasehelper = new Databasehelper (CO ntext, databasehelper.dbname); mdatabase = Mdatebasehelper.getwritabledatabase ();} public static Dao getinstance (context context) {Dao.context = Context;return Daoholder.dao;} Connect and open the database (open database in read-write mode) public void getconnection () {sqlitedatabase sqlitedatabase = null;try {mdatebasehelper = new Dat Abasehelper (context, databasehelper.dbname);} catch (Exception e) {e.printstacktrace ();}} Connect and open the database (open the database in read-write mode) public static VOID open () {mdatabase = Mdatebasehelper.getreadabledatabase ();} public static void CreateTable () {if (!mdatabase.isopen () ) {open ();} Mdatabase.execsql ("CREATE TABLE IF not EXISTS priasetable (ID integer primary key autoincrement,clickid varchar)," + "C Licktype varchar (+), Clickcount integer,nativeclick INTEGER); Mdatabase.close (); public static void Createrecordtable () {if (!mdatabase.isopen ()) {open ()}; Mdatabase.execsql ("CREATE TABLE IF not EXISTS playrecordtable (ID integer PRIMARY key autoincrement,playid varchar (100)," + "Playtype varchar", path varchar (+), ADPath varchar (+), APIC varchar (+), Shareurl varchar (+), Title varchar ( (+), time varchar (+)); Mdatabase.close (); public synchronized int Ishasinfors (string clickid, String clicktype) {open (); int id =-1; Cursor cursor = null;try {cursor = mdatabase.query ("priasetable", NULL, "Clickid=? And clicktype=? ", new string[] {clickid,clicktype}, NULL, NULL, NULL), if (Cursor.movetofirst ()) {id = cursor.getint (0);} } catch (Exception e){E.printstacktrace ();} finally {if (null! = Mdatabase) {mdatabase.close ();} if (null! = cursor) {cursor.close ();}} return ID;}

comparison, application and summary of single-case models