粗糙的区别prepareStatement:（为Statement的子类）与Statement

conn = DBFactory.getInstance().getImpl().getConnection();

//方式一：（不推荐）
//pstmt = conn.prepareStatement(" update "+tb+"  set WDNR=? where "+bh+"=?");
//方式二：
pstmt.setBinaryStream(1, doc.getWDNR(), (int) doc.getStreamSize());
pstmt.setString(2, doc.getWDMC());

returnVal = pstmt.executeUpdate();

Connection conn = null;
Statement stmt = null;
ResultSet rs = null;

//用于加载Driver类(jdbc驱动器)
//registerDriver注册java.sql.DriverManager.registerDriver
Class.forName("org.mariadb.jdbc.Driver").newInstance();

String url = "jdbc:mariadb://192.168.1.100:3306/test?user=root&password=pdcss";
conn = DriverManager.getConnection(url);

stmt = conn.createStatement();
rs = stmt.executeQuery(sql);