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我的DBConnection

Posted on 2007-02-08 14:41 東舟閱讀(1212) 評論(2) 編輯收藏所屬分類: J2EE

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import ?org.apache.log4j.Logger;
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import ?JAVA.sql. * ;
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import ?javax.sql.DataSource;
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import ?javax.naming.Context;
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??6

import ?config.ConfigBundle;
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public ? class ?DBConnection? {
??9

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? private ? static ? final ?Logger?logger? = ?Logger.getLogger(DBConnection. class );
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? private ? static ?DBConnection?instance? = ? null ;
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?
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? public ?JAVA.sql.Connection?conn? = ? null ;? // ?connection?object
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? public ?ResultSet?rs? = ? null ;? // ?resultset?object
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? public ?Statement?stmt? = ? null ;? // ?statement?object
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? public ?PreparedStatement?prepstmt? = ? null ;? // ?preparedstatement?object
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? private ?String?drivers? = ? null ;? // ?connection?parameter:drivers
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? private ?String?url? = ? null ;? // ?connection?parameter:url
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? private ?String?user? = ? null ;? // ?connection?parameter:user
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? private ?String?password? = ? null ;? // ?connection?parameter:password
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?
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? private ?String?conMode? = ? null ;
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?
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? public ?DataSource?ds? = ? null ;
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? public ?CallableStatement?callstmt? = ? null ;
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?
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/**
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?*?單實例
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? */
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? public ? static ? synchronized ?DBConnection?getInstance()? {
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?? if ?(instance == null )
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???instance = new ?DBConnection();
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??
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?? return ?instance;
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?}
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? private ?DBConnection()? {
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??conMode? = ?ConfigBundle.getString( " connction_mode " );
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??init(conMode);
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?? // 使用xa協(xié)議的連接池驅(qū)動時,?AutoCommit缺省為false,?造成多處數(shù)據(jù)未提交
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?? try ? {
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???setAutoCommit( true );
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??} ? catch ?(Exception?ex)? {
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???logger.error( " Set?auto?commit?error! " );
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??}
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?}
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?
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? /**
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??*?原來是采用配置文件確定構(gòu)造方式，這里我只用一種構(gòu)造方式，即conMode沒有起作用
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??*? @param ?conMode?String
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?? */
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? private ? void ?init(String?conMode)? {
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??drivers? = ?ConfigBundle.getString( " drivers " );
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??url? = ?ConfigBundle.getString( " url " );
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??user? = ?ConfigBundle.getString( " user " );
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??password? = ?ConfigBundle.getString( " password " );
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??jndiRoot? = ?ConfigBundle.getString( " jndi_root " );
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??jndiName? = ?ConfigBundle.getString( " jndi_name " );
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??
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?? try ? {
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????Class.forName(drivers);
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????conn? = ?DriverManager.getConnection(url,?user,?password);
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????stmt? = ?conn.createStatement();
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??} ? catch ?(Exception?ex)? {
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???logger.error( " Initialize?data?connection?error! " );
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??}
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?}
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?
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? /**
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??*?@function?executeQuery
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??*? @param ?sql??String
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??*? @throws ?SQLException
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??*? @return ?ResultSet
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?? */
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? public ?ResultSet?executeQuery(String?sql)? throws ?SQLException? {
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?? if ?(stmt? != ? null )? {
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??? return ?stmt.executeQuery(sql);
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??} ? else ? {
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??? return ? null ;
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??}
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?}
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? /**
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??*?@function?executeUpdate
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??*? @param ?sql??String
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??*? @throws ?SQLException
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?? */
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? public ? void ?executeUpdate(String?sql)? throws ?SQLException? {
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?? if ?(stmt? != ? null )? {
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???stmt.executeUpdate(sql);
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??}
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?}
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/**
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??*?@function?setAutoCommit
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??*? @param ?value?boolean
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??*? @throws ?SQLException
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?? */
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? public ? void ?setAutoCommit( boolean ?value)? throws ?SQLException? {
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?? this .conn.setAutoCommit(value);
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?}
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? /**
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??*?@function?commit
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??*? @throws ?SQLException
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?? */
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? public ? void ?commit()? throws ?SQLException? {
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?? this .conn.commit();
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?}
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? /**
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??*?@function?rollback
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??*? @throws ?SQLException
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?? */
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? public ? void ?rollback()? throws ?SQLException? {
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?? this .conn.rollback();
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?}
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? /**
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??*?@function?close
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??*? @throws ?Exception
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?? */
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? public ? void ?close()? {
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?? try ? {
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??? if ?(rs? != ? null )? {
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????rs.close();
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????rs? = ? null ;
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???}
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??} ? catch ?(Exception?e)? {
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???logger.error( " DBConnection?close?rs?error! " );
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??} ? finally ? {
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??? try ? {
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???? if ?(stmt? != ? null )? {
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?????stmt.close();
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?????stmt? = ? null ;
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????}
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???} ? catch ?(Exception?e)? {
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????logger.error( " DBConnection?close?stmt?error! " );
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???} ? finally ? {
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???? try ? {
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????? if ?(prepstmt? != ? null )? {
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??????prepstmt.close();
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??????prepstmt? = ? null ;
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?????}
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????} ? catch ?(Exception?e)? {
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?????logger.error( " DBConnection?close?prepstmt?error! " );
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????} ? finally ? {
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????? try ? {
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?????? if ?(conn? != ? null )? {
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???????conn.close();
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???????conn? = ? null ;
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??????}
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?????} ? catch ?(Exception?e)? {
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??????logger.error( " DBConnection?close?conn?error! " );
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?????}
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????}
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???}
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??}
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?}
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}
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這是個最簡單的，當(dāng)然還可以添加其他內(nèi)容，比如事務(wù)處理一組SQL...
歡迎大家批評指正。

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# re: 我的DBConnection 回復(fù) 更多評論

2007-02-08 15:23 by 馬嘉楠

....
Connection ，ResultSet ， Statement

這三個每次使用之后你都不進行關(guān)閉么？

# re: 我的DBConnection 回復(fù) 更多評論

2007-02-10 12:04 by 東舟

謝謝馬嘉楠的批評。

但是調(diào)用程序里是這樣寫的：
DBConnection db = DBConnection.getInstance();
String strTitle = "";
try {
ResultSet rs = db.executeQuery("select name from TB_PAGEFRAME where type = '1'");
while(rs.next()){
strTitle = rs.getString("name");
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
db.close();
}

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# re: 我的DBConnection 回復(fù) 更多評論

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