隨筆 - 251 
文章 - 504 
trackbacks - 0


           
	

          

          
	
		
          
			
          
	
          
		
          <2006年12月>
          
	
          日一二三四五六
          262728293012
          3456789
          10111213141516
          17181920212223
          24252627282930
          31123456
          

          

          
			


          
	本博客系個人收集材料及學(xué)習(xí)記錄之用，各類“大俠”勿擾！ 


          

			

          留言簿(14)
          




		
          隨筆分類
          
		
				
			
	
		
          收藏夾
          
		
				
			
	
		
          My Favorite Web Sites
          
		
				
			
	
		
          名Bloger
          
		
				
			
	
		
          非著名Bloger
          
		
				
			
	




          搜索
          

            
	
          • 
		
          •  
	
            • 

          


          積分與排名
          

            
	
          • 
		積分 -
		202841
	
          • 
		排名 -
		284
	
            • 

          


          最新評論
	
          

          
	
			
		

          

          		
	

          

          
	
					


          
	
	下面會通過一個獲得數(shù)據(jù)源的例子來比較下傳統(tǒng)編碼模式和IoC編碼模式的不同。首先，在傳統(tǒng)編碼方式下，我們可能這樣獲得數(shù)據(jù)源并顯示結(jié)果：
          package?com.lnic.ioc;

          import?javax.sql.DataSource;
          import?java.sql.Connection;
          import?java.sql.Statement;
          import?java.sql.ResultSet;
          import?java.sql.SQLException;
          import?org.apache.commons.dbcp.BasicDataSource;

          public?class?BasicDataSourceExample?{

          ????          public?static?void?main(String[]?args)?{
          ????????DataSource?dataSource?          =?setupDataSource();

          ????????          //?創(chuàng)建JDBC數(shù)據(jù)源
          ????????Connection?conn?=?null;
          ????????Statement?stmt?          =?null;
          ????????ResultSet?rset?          =?null;

          ????????          try?{
          ????????????
          ????????????conn?          =?dataSource.getConnection();
          ????????????stmt?          =?conn.createStatement();
          ????????????rset?          =?stmt.executeQuery("select?*?from?user");
          ????????????System.out.println(          "Basic?DataSource?executing?results:");
          ????????????          int?numcols?=?rset.getMetaData().getColumnCount();
          ????????????          while?(rset.next())?{
          ????????????????          for?(int?i?=?1;?i?<=?numcols;?i++)?{
          ????????????????????System.out.print(          "\t"?+?rset.getString(i));
          ????????????????}
          ????????????????System.out.println(          "");
          ????????????}
          ????????}          ?catch?(SQLException?e)?{
          ????????????e.printStackTrace();
          ????????}          ?finally?{
          ????????????          try?{
          ????????????????rset.close();
          ????????????}          ?catch?(Exception?e)?{
          ????????????}
          ????????????          try?{
          ????????????????stmt.close();
          ????????????}          ?catch?(Exception?e)?{
          ????????????}
          ????????????          try?{
          ????????????????conn.close();
          ????????????}          ?catch?(Exception?e)?{
          ????????????}
          ????????}
          ????}

          ????          //?創(chuàng)建數(shù)據(jù)源
          ????public?static?DataSource?setupDataSource()?{
          ????????BasicDataSource?ds?          =?new?BasicDataSource();
          ????????ds.setDriverClassName(          "com.mysql.jdbc.Driver");
          ????????ds.setUsername(          "root");
          ????????ds.setPassword(          "131421");
          ????????ds.setUrl(          "jdbc:mysql://localhost:3306/test");
          ????????          return?ds;
          ????}

          ????          //?提示數(shù)據(jù)源狀態(tài)
          ????public?static?void?printDataSourceStats(DataSource?ds)?throws?SQLException?{
          ????????BasicDataSource?bds?          =?(BasicDataSource)?ds;
          ????????System.out.println(          "NumActive:?"?+?bds.getNumActive());
          ????????System.out.println(          "NumIdle:?"?+?bds.getNumIdle());
          ????}

          ????          //?關(guān)閉數(shù)據(jù)源
          ????public?static?void?shutdownDataSource(DataSource?ds)?throws?SQLException?{
          ????????BasicDataSource?bds?          =?(BasicDataSource)?ds;
          ????????bds.close();
          ????}
          }
          這個累的測試結(jié)果顯示：
          Basic DataSource executing results:
          ?123?matthew?YunNanUniversity
          ?1?lidexian?YunNanUniversity
          ?2?zhangzili?HunanUniversity

          而在Spring 的IoC容器的幫助下我們的編碼會更簡單和靈活。首先，定義個Spring的配置文件：applicationContext.xml。在這個配置文件中，我們配置了三個bean組件，代表不同的數(shù)據(jù)庫數(shù)據(jù)源。然后，通過配置jdbcTemplate來啟用需要的具體數(shù)據(jù)庫數(shù)據(jù)源。如下：我們采用的MySql數(shù)據(jù)源。
          <?xml?version="1.0"?encoding="UTF-8"?>
          <!DOCTYPE?beans?PUBLIC?"-//SPRING//DTD?BEAN//EN"?"http://www.springframework.org/dtd/spring-beans.dtd">
          <beans>
          ????          <bean?id="oracle_dataSource"?class="org.apache.commons.dbcp.BasicDataSource"?destroy-method="close">
          ????????          <property?name="driverClassName"?value="oracle.jdbc.driver.OracleDriver"?/>
          ????????          <property?name="url"?value="jdbc:oracle:thin:@localhost:1521:cyberdb"?/>
          ????????          <property?name="username"?value="scott"?/>
          ????????          <property?name="password"?value="tiger"?/>
          ????          </bean>
          ????
          ????
          ????
          ????          <bean?id="mysql_dataSource"?class="org.apache.commons.dbcp.BasicDataSource"?destroy-method="close">
          ????????          <property?name="driverClassName"?value="com.mysql.jdbc.Driver"?/>
          ????????          <property?name="url"?value="jdbc:mysql://localhost:3306/test"?/>
          ????????          <property?name="username"?value="root"?/>
          ????????          <property?name="password"?value="131421"?/>
          ????          </bean>
          ????
          ????          <bean?id="linux_oracle_dataSource"?class="org.apache.commons.dbcp.BasicDataSource"?destroy-method="close">
          ????????          <property?name="driverClassName"?value="oracle.jdbc.driver.OracleDriver"?/>
          ????????          <property?name="url"?value="jdbc:oracle:thin:@192.168.0.3:1521:linuxdb"?/>
          ????????          <property?name="username"?value="scott"?/>
          ????????          <property?name="password"?value="tiger"?/>
          ????          </bean>

          ????          <bean?id="jdbcTemplate"?class="org.springframework.jdbc.core.JdbcTemplate"?lazy-init="true">
          ????????          <property?name="dataSource">
          ????????????          <ref?local="mysql_dataSource"?/>
          ????????          </property>
          ????          </bean>

          ????
          </beans>


          然后，如下在代碼中通過載入Spring的配置文件，并初始化bean組件：jdbcTemplate得到數(shù)據(jù)源，并完成數(shù)據(jù)查詢。可以看出比傳統(tǒng)的方法簡單和靈活多了，只需要簡單配置即可完成。
          package?com.lnic.ioc;

          import?java.sql.ResultSet;
          import?java.sql.SQLException;
          import?java.util.ArrayList;
          import?java.util.List;

          import?org.springframework.context.ApplicationContext;
          import?org.springframework.context.support.ClassPathXmlApplicationContext;
          import?org.springframework.jdbc.core.JdbcTemplate;
          import?org.springframework.jdbc.core.RowCallbackHandler;

          public?class?IocDataSourceExample?{
          ????          public?static?void?main(String[]?args)?{
          ????????ApplicationContext?ctx?          =?new?ClassPathXmlApplicationContext(
          ????????????????          "com/lnic/ioc/applicationContext.xml");//載入spring配置文件applicationContext.xml

          ????????String?sql?          =?"select?*?from?user";
          ????????JdbcTemplate?jt?          =?(JdbcTemplate)?ctx.getBean("jdbcTemplate");//這里采用spring的JdbcTemplate，通過spring的配置文件啟用mysql_dataSource數(shù)據(jù)源。
          ????????jt.query(sql,?new?RowCallbackHandler()?{
          ????????????          public?void?processRow(ResultSet?rs)?throws?SQLException?{
          ????????????????          //?do?something?with?the?rowdata?-?like?create?a?new
          ????????????????          //?object?and?add?it?to?the?List?in?the?enclosing?code
          ????????????????System.out.println("IocDataSource?executing?results:");
          ????????????????          int?numcols?=?rs.getMetaData().getColumnCount();
          ????????????????
          ????????????????          do?{
          ????????????????????          for?(int?i?=?1;?i?<=?numcols;?i++)?{
          ????????????????????????System.out.print(          "\t"?+?rs.getString(i));
          ????????????????????}
          ????????????????????System.out.println(          "");
          ????????????????}          ?while?(rs.next());
          ????????????}
          ????????}          );
          ????}
          }

          代碼輸出如下：
          IocDataSource executing results:
          ?123?matthew?YunNanUniversity
          ?1?lidexian?YunNanUniversity
          ?2?zhangzili?HunanUniversity
	
          posted on 2006-12-26 13:25 matthew 閱讀(459) 評論(0)  編輯  收藏  所屬分類: JavaEE 
          

          







          
	    
    




          








          

				
	



          



    







          
        
	




主站蜘蛛池模板：
绥化市|
额尔古纳市|
清镇市|
汉川市|
敖汉旗|
金坛市|
开化县|
四会市|
商都县|
锦州市|
巴彦淖尔市|
仁布县|
屏山县|
内乡县|
汉寿县|
南平市|
苏尼特右旗|
青龙|
尼玛县|
惠来县|
长海县|
得荣县|
呼玛县|
来凤县|
锡林浩特市|
花莲市|
上虞市|
陕西省|
五家渠市|
高平市|
巫山县|
清水县|
尉犁县|
吐鲁番市|
津南区|
汾阳市|
黑河市|
黑山县|
彭阳县|
贡觉县|
当雄县|