teeth/Dao.java

package com.dao;
import java.sql.*;
import javax.sql.DataSource;
import javax.naming.*;
public interface Dao {
    public static DataSource getDataSource(){
	   DataSource dataSource = null;
	   try {
	      Context context = new InitialContext();
	      dataSource = 
            (DataSource)context.lookup("java:comp/env/jdbc/webstoreDS");
	      System.out.println("这里到了吗");
	  }catch(NamingException ne){
	     System.out.println("异常:"+ne);
	     System.out.println("查找数据源不成功");
	  }
	  return dataSource;
	}
    public default Connection getConnection() throws SQLException {
    	System.out.println("这里");
	   DataSource dataSource = getDataSource();
	   System.out.println("那这");
	   Connection conn = null;
	   try{
		   System.out.println("连接");
		   conn =  dataSource.getConnection(); //
		   System.out.println("连接成功");
	   }catch(SQLException sqle){
		   System.out.println("异常:"+sqle);  
		   System.out.println("链接失败");
	   }
	   return  conn;
   }	
}