Java basic methods to connect to the database and execute the query, do you see what's wrong with this?

package com.yuan.test;import java.io.ioexception;import java.sql.connection;import  java.sql.drivermanager;import java.sql.sqlexception;public class test123 {public  Test123 ()  {}public static void main (String[]args) {User user=new user ("123",   "YUANW",  "man",  "yuanw"); Test123 test123=new test123 (); try {test123.updateuser (user);}  catch  (sqlexception e)  {// TODO Auto-generated catch  Blocke.printstacktrace ();}} Public void updateuser (User user)  throws java.sql.sqlexception { Java.lang.stringbuffer sqlbuf = new java.lang.stringbuffer (); SqlBuf.append ("Update T_ User set user_name= ' "); Sqlbuf.append (User.getusername ()); Sqlbuf.append (" ', "); Sqlbuf.append (" SEX= "); Sqlbuf.append (User.getsex ()), Sqlbuf.append ("',"); Sqlbuf.append ("email="); Sqlbuf.append (User.getemail ()); Sqlbuf.append ("'  WHERE&NBsp;userid= "); Sqlbuf.append (User.getid ()); String sql = sqlbuf.tostring (); SYSTEM.OUT.PRINTLN ("Print update UPDATE statement:" +sql); Java.sql.connection con = getconnectionfromdatasource () ; Java.sql.statement stmt = con.createstatement (); stmt.executeupdate (SQL); Stmt.close (); con.close ();} Private connection getconnectionfromdatasource ()  {String driverName =  " Com.microsoft.sqlserver.jdbc.SQLServerDriver "; //  load JDBC driver string dburl = " JDBC: Sqlserver://localhost:1433; databasename=hibernate "; //  connection server and database teststring username  =  "sa"; //  Default user name string userpwd =  "sa123"; //  password connection dbconn  = null;try {class.forname (drivername);}  catch  (classnotfoundexception e)  {// TODO Auto-generated catch  Blocke.printstacktrace ();} Try {dbconn = drivermanager.getconnection (dburl, username, USERPWD); System.out.println ("connection successful!");  //  If the connection succeeds   console output connection} catch  (sqlexception e)  {// TODO  Auto-generated catch blocke.printstacktrace ();}  successful!return dbconn;}}

Note: The Sqljdbc4.jar package needs to be introduced

Tip: Modify the Table field property values.

ALTER TABLE tablename ALTER COLUMN colname Newdatatype

@@ 兄弟 all help me to see, so write call will have what problem???

Java basic methods to connect to the database and execute the query, do you see what's wrong with this?