JDBC工具类创建及使用

 1

import java.io.FileInputStream;
import java.sql.*;
import java.util.Properties;

/**
 * @author o_0sky
 * @date 2019/2/19 0:10
 */
public class Jdbcutil {
    static String driverName;
    static String url;
    static String user;
    static String pwd;

    //不论外面调用多少次getConnection方法,驱动都只要注册一次
    static {
        try {
            Properties p = new Properties();
            p.load(new FileInputStream("jdbc.properties"));
            //给参数赋值
            driverName = p.getProperty("driverName");
            url = p.getProperty("url");
            user = p.getProperty("user");
            pwd = p.getProperty("pwd");
            Class.forName(driverName);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //获取连接
    public static Connection getConnection() throws SQLException {
        Connection con = DriverManager.getConnection(url,user,pwd);
        return con;
    }
    //释放资源
    public static  void release(Connection con, Statement statement, ResultSet resultSet){
        if (resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (statement!=null){
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (con!=null){
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

测试类：

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

/**
 * @author o_0sky
 * @date 2019/2/19 0:38
 */
public class Test {
    public static void main(String[] args) throws SQLException {
        //需要执行的Sql语句
        String sql = "select * from tb_user";
        //通过工具类获取连接
        Connection con = Jdbcutil.getConnection();
        Statement statement = con.createStatement();
        //执行sql语句
        ResultSet resultSet = statement.executeQuery(sql);
        while (resultSet.next()) {
            String name = resultSet.getString("name");
            String age = resultSet.getString("age");
        }
        //释放资源
        Jdbcutil.release(con, statement, resultSet);
    }
}