JDBC连接工具类

package com.ins.db;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class DBconn {
	//declare var 
	private String driver="";
	private String url="";
	private String uname="";
	private String passwd="";
	private Connection conn=null;
	private Statement stmt=null;
	private static ResultSet rs=null;
	private static final String DATABASE_PROPERTIES="jdbc.properties";//定义配置文件
	
	//load properties
	public DBconn(){
		loadProperties();
		setConn();
	}
	//load conf
	private void loadProperties(){
		InputStream in =DBconn.class.getResourceAsStream(DATABASE_PROPERTIES);//读入配置文件
		//定义Properties
		Properties p=new Properties();
		try {
			p.load(in);
		} catch (IOException e) {
			e.printStackTrace();
		}
		//得到配置文件并将其值赋给当前变量
		this.driver=p.getProperty("driver");
		this.url=p.getProperty("url");
		this.uname=p.getProperty("username");
		this.passwd=p.getProperty("password");
	}
	//setConn
	private void setConn(){
		try {
			Class.forName(driver);  
			this.conn=DriverManager.getConnection(url,uname,passwd);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	
	//getConn
	public  Connection getConn(){
		return this.conn;
	}
	
//=================================CRUD===========================
	//执行插入
	public  void doInsert(String sql){
		try {
			stmt=conn.createStatement();
			stmt.executeUpdate(sql);
		} catch (SQLException e) {
			e.printStackTrace();
			System.err.println("db.executeInset:" + e.getMessage());   
		}finally{
			colseAll(rs,stmt,conn);
		}
	}
	//	执行删除
	public  void doDelete(String sql){
		try {
			stmt=conn.createStatement();
			stmt.executeUpdate(sql);
		} catch (SQLException e) {
			e.printStackTrace();
			System.err.println("db.executeInset:" + e.getMessage());   
		}finally{
			colseAll(rs,stmt,conn);
		}
	}
	
//	执行更新
	public  void doUpdate(String sql){
		try {
			stmt=conn.createStatement();
			stmt.executeUpdate(sql);
		} catch (SQLException e) {
			e.printStackTrace();
			System.err.println("db.executeInset:" + e.getMessage());   
		}finally{
			colseAll(rs,stmt,conn);
		}
	}
//	查询结果集   
    public  ResultSet doSelect(String sql) {   
        try {   
            stmt = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);   
            rs = stmt.executeQuery(sql);   
        } catch(SQLException sqlexception) {   
            System.err.println("db.executeQuery: " + sqlexception.getMessage());   
        }   
        return rs;   
    } 
    
//=============================================CRUD end========================
	//close rs
	public  static void colseRs(ResultSet rs){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs=null;
		}
	}
//	close stmt
	public  static void colseStmt(Statement stmt){
		if(stmt!=null){
			try {
				stmt.close();
			} catch (SQLException es) {
				es.printStackTrace();
			}
			stmt=null;
		}
	}
//	close conn
	public  void colseConn(Connection conn){
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException ec) {
				ec.printStackTrace();
			}
			conn=null;
		}
	}
//close all
	public static void colseAll(ResultSet rs,Statement stmt,Connection conn){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs=null;
		}
		if(stmt!=null){
			try {
				stmt.close();
			} catch (SQLException es) {
				es.printStackTrace();
			}
			stmt=null;
		}
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException ec) {
				ec.printStackTrace();
			}
			conn=null;
		}
	}
	public static void main(String[] args) {
		DBconn db=new DBconn();
		String sql="select *from class";
		rs=db.doSelect(sql);
		
		try {
			while(rs.next()){
				System.out.println(rs.getInt(1));
				System.out.println(rs.getString(2));
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

MySQL：       
    String Driver="com.mysql.jdbc.Driver";    //驱动程序   
    String URL="jdbc:mysql://localhost:3306/db_name";    //连接的URL,db_name为数据库名       
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).new Instance();   
    Connection con=DriverManager.getConnection(URL,Username,Password);   
Microsoft SQL Server 2.0驱动(3个jar的那个):   
    String Driver="com.microsoft.jdbc.sqlserver.SQLServerDriver";    //连接SQL数据库的方法   
    String URL="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db_name";    //db_name为数据库名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).new Instance();    //加载数据可驱动   
    Connection con=DriverManager.getConnection(URL,UserName,Password);    //   
Microsoft SQL Server 3.0驱动(1个jar的那个): // 老紫竹完善   
    String Driver="com.microsoft.sqlserver.jdbc.SQLServerDriver";    //连接SQL数据库的方法   
    String URL="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db_name";    //db_name为数据库名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).new Instance();    //加载数据可驱动   
    Connection con=DriverManager.getConnection(URL,UserName,Password);    //   
Sysbase:   
    String Driver="com.sybase.jdbc.SybDriver";    //驱动程序   
    String URL="jdbc:Sysbase://localhost:5007/db_name";    //db_name为数据可名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).newInstance();       
    Connection con=DriverManager.getConnection(URL,Username,Password);   
Oracle(用thin模式):   
    String Driver="oracle.jdbc.driver.OracleDriver";    //连接数据库的方法   
    String URL="jdbc:oracle:thin:@loaclhost:1521:orcl";    //orcl为数据库的SID   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).newInstance();    //加载数据库驱动   
    Connection con=DriverManager.getConnection(URL,Username,Password);       
PostgreSQL:   
    String Driver="org.postgresql.Driver";    //连接数据库的方法   
    String URL="jdbc:postgresql://localhost/db_name";    //db_name为数据可名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).newInstance();       
    Connection con=DriverManager.getConnection(URL,Username,Password);   
DB2：   
    String Driver="com.ibm.db2.jdbc.app.DB2.Driver";    //连接具有DB2客户端的Provider实例   
    //String Driver="com.ibm.db2.jdbc.net.DB2.Driver";    //连接不具有DB2客户端的Provider实例   
    String URL="jdbc:db2://localhost:5000/db_name";    //db_name为数据可名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).newInstance();       
    Connection con=DriverManager.getConnection(URL,Username,Password);   
Informix:   
    String Driver="com.informix.jdbc.IfxDriver";       
    String URL="jdbc:Informix-sqli://localhost:1533/db_name:INFORMIXSER=myserver";    //db_name为数据可名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).newInstance();       
    Connection con=DriverManager.getConnection(URL,Username,Password);   
JDBC-ODBC:   
    String Driver="sun.jdbc.odbc.JdbcOdbcDriver";   
    String URL="jdbc:odbc:dbsource";    //dbsource为数据源名   
    String Username="username";    //用户名   
    String Password="password";    //密码   
    Class.forName(Driver).newInstance();       
    Connection con=DriverManager.getConnection(URL,Username,Password);