JDBC——阶段性总结-蒲公英云

JDBC——阶段性总结

向右看齐 2022-11-25 13:10 230阅读 0赞

1、JDBC工作流程

添加jar依赖
Class.forName(“驱动”)
Connection con=DriverManager.getConnection(url,username,pwd);
PrepareStatement ps=con.PrepareStatement(sql); Ps.setString(1,””);
Insert update delete—- int ret=ps.executeUpdate(); Select —-ResultSet rs=ps.executeQuery();
遍历结果集ResultSet
关闭资源，后创建的先关闭

2、封装了工具类

public class DruidUtils {
    private static DruidDataSource dataSource=null;
    private static ThreadLocal<Connection> threadLocal;
    static{
        //1 创建流
        try {
            threadLocal=new ThreadLocal<>();
            InputStream is = DruidUtils.class.getClassLoader().getResourceAsStream("database.properties");
            Properties properties=new Properties();
            properties.load(is);
            dataSource= (DruidDataSource) DruidDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("初始化连接池失败....");
            //日志
        }
    }
    //获取数据源
    public static DataSource getDataSource(){
        return dataSource;
    }
    //获取连接
    public static Connection getConnection() throws SQLException {
        Connection conn=threadLocal.get(); //Thread.curentThread;
        if(conn==null){
            conn=dataSource.getConnection();
            //放入threadLocal
            threadLocal.set(conn);
        }
        return  conn;
    }
    //开启事务
    public static void beginTransaction() throws  SQLException{
        Connection conn = getConnection();
        conn.setAutoCommit(false);
    }
    //提交事务
    public static void commit() throws SQLException{
        Connection conn = getConnection();
        conn.commit();
    }
    //回滚事务
    public static void roolback() throws SQLException{
        Connection conn = getConnection();
        conn.rollback();
    }
    //关闭
    public static void close() throws SQLException{
        Connection conn = getConnection();
        conn.close();
        threadLocal.remove();
    }
}