java操作数据库

1.连接-增删改查数据库

//加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        //创建连接
        Connection conn = DriverManager.getConnection("jdbc:sqlserver://127.0.0.1:1433;databaseName=jeecg-bpm","username","password");
        Statement stat = conn.createStatement();
        
        //更新ip
        stat.execute("update t_s_base_user set ip = '127.0.0.1' where username = 'admin'");
        stat.close();
        conn.close();

2.sql查询时，where条件可以是变量，操作如下：

ResultSet dbusername = stat.executeQuery("select ip from table where username = '"+ curusername+"'");