Java EE WEB工程师培训-JDBC+Servlet+JSP整合开发之05.JDBC MetaData

package com.michael.jdbc;    

import java.sql.Connection;    
import java.sql.DriverManager;    
import java.util.Properties;    

public  class ConnectionUtil {    
         //第一种方法    
         public Connection getConnection(){    
                Connection conn =  null;    
                 try {    
                         //Class.forName加载驱动    
                        Class.forName( "com.mysql.jdbc.Driver");    
                         //DriverManager获得连接    
                        conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/jdbc_db","root","mysqladmin");    
                        return conn;    
                } catch (Exception e) {    
                        e.printStackTrace();    
                }    
                return null;    
        }    
        //第二种方法    
        public Connection getConnection(String driver,String url,String user,String password){    
                Connection conn = null;    
                try {    
                        //Class.forName加载驱动    
                        Class.forName(driver);    
                        //DriverManager获得连接    
                        conn = DriverManager.getConnection(url,user,password);    
                        return conn;    
                } catch (Exception e) {    
                        e.printStackTrace();    
                }    
                return null;    
        }    
        //第三种方法    
        public Connection openConnection(){    
                String driver = "";    
                String url = "";    
                String user = "";    
                String password = "";    
                Properties prop = new Properties();    
                Connection conn = null;    
                try {    
                        //加载属性文件    
                        prop.load(this.getClass().getClassLoader().getResourceAsStream("DBConfig.properties"));    
                        driver = prop.getProperty("driver");    
                        url = prop.getProperty("url");    
                        user = prop.getProperty("user");    
                        password = prop.getProperty("password");    
                        //Class.forName加载驱动    
                        Class.forName(driver);    
                        //DriverManager获得连接    
                        conn = DriverManager.getConnection(url,user,password);    
                        return conn;    
                } catch (Exception e) {    
                        e.printStackTrace();    
                }    
                return null;    
        }    

} 

package com.michael.jdbc;    

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

public  class TestMetaData {    
         public  static  void test(){    
                Connection conn =  new ConnectionUtil().openConnection();    
                 try {    
                        Statement stmt = conn.createStatement();    
                        String sql =  "select * from CustomerTbl";    
                        ResultSet rs = stmt.executeQuery(sql);    
                        ResultSetMetaData rsmd = rs.getMetaData();    
                         int columns = rsmd.getColumnCount();    
                         for ( int i=1;i<=columns;i++){    
                                String name = rsmd.getColumnName(i);    
                                 int type = rsmd.getColumnType(i);    
                                System.out.println(name+ ":"+type);    
                        }    
                }  catch (SQLException e) {    
                        e.printStackTrace();    
                } finally{    
                                 try {    
                                        conn.close();    
                                }  catch (SQLException e) {    
                                        e.printStackTrace();    
                                }    
                }    
        }    
} 

package com.michael.main;    

import com.michael.jdbc.TestMetaData;    

public  class Main {    

         /**    
         * @param args    
         */    
         public  static  void main(String[] args) {    
                TestMetaData.test();    
        }    
} 

package com.michael.jdbc;    

import java.sql.Connection;    
import java.sql.DatabaseMetaData;    
import java.sql.SQLException;    

public  class TestMetaData {    
         public  static  void test(){    
                Connection conn =  new ConnectionUtil().openConnection();    
                 try {    
                        DatabaseMetaData dbmd = conn.getMetaData();    
                        System.out.println(dbmd.getDatabaseProductName());    
                        System.out.println(dbmd.getDatabaseMajorVersion());    
                }  catch (SQLException e1) {    
                        e1.printStackTrace();    
                } finally{    
                         try {    
                                conn.close();    
                        }  catch (SQLException e) {    
                                e.printStackTrace();    
                        }    
                }    
                 /*    
                try {    
                        Statement stmt = conn.createStatement();    
                        String sql = "select * from CustomerTbl";    
                        ResultSet rs = stmt.executeQuery(sql);    
                        ResultSetMetaData rsmd = rs.getMetaData();    
                        int columns = rsmd.getColumnCount();    
                        for (int i=1;i<=columns;i++){    
                                String name = rsmd.getColumnName(i);    
                                int type = rsmd.getColumnType(i);    
                                System.out.println(name+":"+type);    
                        }    
                } catch (SQLException e) {    
                        e.printStackTrace();    
                }finally{    
                                try {    
                                        conn.close();    
                                } catch (SQLException e) {    
                                        e.printStackTrace();    
                                }    
                }    
                */    
        }    
}