java学习之联接Mysql

java 学习之连接 Mysql 首先导入 mysql-connector-java-5.1.10-bin.ja 下载地址： http://download.csdn.net/detail/u014112584/7359185 鼠标放在项目上，右击选择Properties-----Java Build Path ------Add External JARS 测试代码： import java.sql.Connec

首先导入mysql-connector-java-5.1.10-bin.ja

下载地址：http://download.csdn.net/detail/u014112584/7359185

鼠标放在项目上，右击选择Properties----->Java Build Path ------>Add External JARS

测试代码：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.Statement;


public class MysqlTest {
	
	static String drivername="com.mysql.jdbc.Driver";
    static String url="jdbc:mysql://localhost:3306/expression";//指向数据源
    static String username="root";
    static String password="";
    static java.sql.Statement stmt=null;
    static ResultSet re=null;
    static Connection conn=null;
    static PreparedStatement pstm=null;
    /*
     * 构造函数进行初始化
     */
    public MysqlTest(){
    	try{
    		Class.forName(drivername);//将驱动加载到运行环境中，加载的时候，驱动会自动向DriverManager完成注册
    		System.out.println("创建驱动成功");
    	}catch(ClassNotFoundException e){
    		e.printStackTrace();
    	}
    }
    /*
     * 获取连接
     */
    public static Connection getConnection(){
   	 conn=null;
   	try{
   		conn=(Connection)DriverManager.getConnection(url, username, password);//有了驱动和连接地址后，需要使用DriverManager来获取连接
   		System.out.println("连接数据库成功！");
   	}catch(SQLException e){
   		e.printStackTrace();
   	}
   	return conn;
   }
    /**
     * 关闭连接
     * @param args
     */
    public static void free(ResultSet rs,Connection conn,java.sql.Statement stmt2){
    	if(rs!=null){
    		try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				System.out.println("关闭ResultSet失败！");
				e.printStackTrace();
			}finally{
				if(conn!=null){
					try {
						conn.close();
					} catch (SQLException e) {
						// TODO Auto-generated catch block
						System.out.println("关闭Connection失败！");
						e.printStackTrace();
					}finally{
						if(stmt2!=null){
							try {
								stmt2.close();
							} catch (SQLException e) {
								// TODO Auto-generated catch block
							   System.out.println("关闭Statement失败！");
								e.printStackTrace();
							}
						}
					}
				}
			}
    	}
    }
    public static void main(String[]args){

    	MysqlTest.getConnection();
    	try {
			stmt=conn.createStatement();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			re=stmt.executeQuery("select * from data");
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		int i=1;
		try {
			while(re.next()){
				System.out.println(i++);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		free(re,conn,stmt);
		System.out.println("OK");
    }
}