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

区别：
prepareStatement:（为Statement的子类）

conn = DBFactory.getInstance().getImpl().getConnection();
***pstmt = conn.prepareStatement(" update "+tb+"  set WDNR=? where "+bh+"=?");
pstmt.setBinaryStream(1, doc.getWDNR(), (int) doc.getStreamSize());
pstmt.setString(2, doc.getWDMC());
***returnVal = pstmt.executeUpdate();

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Statement:

Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
Class.forName("org.mariadb.jdbc.Driver").newInstance(); //用于加载Driver类(jdbc驱动器)，，，registerDriver注册java.sql.DriverManager.registerDriver
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);