JDBC(五)

抽取JDBC工具类
目的:简化书写
分析:
1.注册驱动的抽取
2.抽取一个方法获取连接对象
3.抽取方法释放资源

package Utils;

import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.*;
import java.util.Properties;

/**
 * JDBC工具类
 */
public class JDBCUtils {
    private static String url;
    private static String user;
    private static String password;
    private static String driver;



    /**
     * 文件的读取,只需要一次即可拿到这些值
     */

    static {
    //读取资源文件,获取值
        //1.创建Properties集合类
        Properties pro = new Properties();
        //获取src路径下的文件方式
        ClassLoader classLoader = JDBCUtils.class.getClassLoader();
        URL res = classLoader.getResource("jdbc.properties");
        String path = res.getPath();

        //2.加载文件
        try {
            pro.load(new FileReader(path));
        } catch (IOException e) {
            e.printStackTrace();
        }
        //3.获取数据,赋值
        url = pro.getProperty(url);
        user = pro.getProperty(user);
        password = pro.getProperty(password);
        driver = pro.getProperty(driver);
        //4.注册驱动
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }




    /**
     * 获取连接
     * @return 连接对象
     */
    public static Connection getConnection(){
        return null;
    }

    public static void close(Statement stmt,Connection conn){
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
    public static void close(ResultSet rs,Statement stmt, Connection conn){
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
}

url=jdbc:mysql:///db3
user=root
password=root
driver=com.mysql.jdbc.Driver