<!-- mysql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.31</version>
        </dependency>    

package com.test;
import java.sql.*; 

public class jdbc {
	public static void main(String[] args) {		
		//数据库连接
		Connection connection = null;
		//预编译的statement
		PreparedStatement preparedStatement = null;
		//结果集
		ResultSet resultSet = null;		
		try{
			//加载数据库驱动
			Class.forName("com.mysql.jdbc.Driver");
			//通过驱动管理类获取数据库链接,用户名及密码
			connection = DriverManager.getConnection("jdbc:mysql://192.168.6.12:3306/test","dev","mybatis");
			//定义sql语句   ？表示占位符
			String sql = "select * from user where userName= ?";
			//获取预处理statement
			preparedStatement = connection.prepareStatement(sql);
			//设置参数，第一个参数为sql语句中参数的序号，第二个参数为设置的参数值
			preparedStatement.setString(1, "小明");
			
			//向数据库发出sql执行查询，查询出结果集
			resultSet = preparedStatement.executeQuery();
			//遍历结果集
			while(resultSet.next()){
				System.out.println(resultSet.getString("id")+"   "+resultSet.getString("username"));
			}
		}catch(Exception e){
			e.printStackTrace();
		}finally{
			//释放资源
			if(resultSet != null){
				try{
					resultSet.close();
				}catch(Exception e){
					e.printStackTrace();
				}
			}
		}
	}
}