個人研究用：
0.去oracle安裝目錄找一個名為class12.jar的jar包，放到項目的lib里
1.在META-INF?建立個context.xml文件
<?xml?version="1.0"?encoding="UTF-8"?>
<Context>
	??<Resource?name="jdbc/crm"??
???????auth="Container"??????
???????type="javax.sql.DataSource"??????
???????driverClassName="oracle.jdbc.driver.OracleDriver"??????
???????url="jdbc:oracle:thin:@localhost:1521:oracle"??????
???????username="crm"??????
???????password="crm"??????
???????maxActive="4"??????
???????maxIdle="2"??????
???????maxWait="3000"/>?
</Context>
2.
//數(shù)據(jù)庫鏈接池?第一個類?用來鏈接數(shù)據(jù)庫
package?com.baidu.crm.common;

import?java.sql.Connection;
import?java.sql.ResultSet;
import?java.sql.SQLException;
import?java.sql.Statement;

import?javax.naming.Context;
import?javax.naming.InitialContext;
import?javax.naming.NamingException;
import?javax.sql.DataSource;

import?org.omg.CORBA.Request;

//連接池
public?class?DataSourceManager?{
		
		public?static?Connection?getConnection(){
			
			DataSource?ds=null;
			
			try?{
				Context?context=new?InitialContext();
				ds=(DataSource)context.lookup("java:comp/env/jdbc/crm");//crm數(shù)據(jù)庫名
			}?catch?(NamingException?e)?{
				e.printStackTrace();
			}
			Connection?con=null;
			try?{
				con=ds.getConnection();
			}?catch?(SQLException?e)?{
				
				e.printStackTrace();
			}
			
			return?con;
		}
	
	public?static?void?closeDBSource(ResultSet?rs,Statement?st,Connection?con){
		
		try?{
			if(rs!=null){
				rs.close();
			}
			if(st!=null){
				st.close();
			}
			if(con!=null){
				con.close();
			}
		}?catch?(SQLException?e)?{
			
			e.printStackTrace();
		}
	}
}

3.//調用鏈接的類
package?com.baidu.crm.dao;

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

import?com.baidu.crm.common.DataSourceManager;
import?com.baidu.crm.entity.City;

public?class?CityDao?{
	
	public?List<City>?getCityList()
	{
		
		List<City>?result=new?ArrayList<City>();
	
		
		Connection?con=null;
		PreparedStatement?ps=null;
		ResultSet?rs=null;
		
		con=DataSourceManager.getConnection();
		
		try?{
			
			ps=con.prepareStatement("select?city_code,city_name?from?city");
		
			
			rs=ps.executeQuery();
			while(rs.next()){
				City?city=new?City();
				city.setCityCode(rs.getInt("city_code"));
				city.setCityName(rs.getString("city_name"));
				
				result.add(city);
			}
			
			
		}?catch?(SQLException?e)?{
			
			e.printStackTrace();
		}finally{
			DataSourceManager.closeDBSource(rs,?ps,?con);
		}
		
		
		
		return?result;
	}

}

你可以往后面看，學jdbc就會了！慕課網(wǎng)有這門課