jdbc技术实现万能查询，增加、删除插入操作

1、在src目录下建立jdbc.propertise文件

user=root//数据库登录账户
password=123456//数据库登录密码
url=jdbc:mysql://localhost:3306/shujukumingzi//这里是url，如果要实现其他指定操作在后面加相应的参数
driverClass=com.mysql.jdbc.Driver//driver驱动

2、对建立数据库连接和关闭操作进行封装，以便之后的一系列操作的调用，这里利用反射技术来建立连接。

public class JDBCUtilse {
    public static Connection getConnection() throws IOException, ClassNotFoundException, SQLException {
        InputStream is = Jdbc_Test5.class.getClassLoader()
                .getResourceAsStream("jdbc.properties");
        Properties properties = new Properties();
        properties.load(is);
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String url = properties.getProperty("url");
        String driverClass = properties.getProperty("driverClass");
        Class.forName(driverClass);
        Connection conn = DriverManager.getConnection(url,user,password);
        return conn;
    }

    public static void close(Connection conn, Statement statement) throws SQLException {
        if(conn != null)
        {
            conn.close();
        }
        if (statement != null)
        {
            statement.close();
        }
    }
}

3、实现通用的select操作 

class PreparedStatement_Test3 {
    public static void main(String[] args) throws SQLException, IOException, ClassNotFoundException {
       
        String sql = "select * from user where id < ?";
        query(sql,3);
    }

    public static void query(String sql,Object...args) throws SQLException, IOException, ClassNotFoundException {
        Connection conn = JDBCUtilse.getConnection();
        PreparedStatement ps = conn.prepareStatement(sql);
        for (int i = 0; i < args.length; i ++)
        {
            ps.setObject(i + 1,args[i]);
        }
        ResultSet rs = ps.executeQuery();
        ResultSetmetaData rsmd = rs.getmetaData();
        int columnCount = rsmd.getColumnCount();
        while (rs.next())
        {
            for (int i = 0; i < columnCount;i++ )
            {
                System.out.print(rs.getObject(i + 1 ) + " ");
            }
            System.out.println();
        }
        rs.close();
        JDBCUtilse.close(conn,ps);
    }
}

4、实现通用insert,delect,update操作

class PreparedStatement_Test2 {
    public static void main(String[] args) throws Exception {
        
        String sql="delect from user where id=? or id=?";
        update(sql,1,2);
    }

    public static void update(String sql,Object...args) throws SQLException, IOException, ClassNotFoundException {
      Connection conn=JDBCUtilse.getConnection();
      PreparedStatement ps=conn.prepareStatement(sql);
      for (int i=0;i<=args.length;i++){
          ps.setObject(i,args[i]);
        }
      ps.executeUpdate();
      JDBCUtilse.close(conn,ps);
}
}

总结：一系列的操作都是建立连接，再关闭，采用数据连接池会更加方便，三种连接池均可。