使用占位符的插入语句

Question

…… public static void insert(String name,String password) throws Exception{   Connection conn = null;   PreparedStatement st = null;   ResultSet rs =null;   conn = DbUtils.getConn(); String sql="insert into User(name,password) values(?,?)";         st = conn.prepareStatement(sql);                  st.setString(1,name);         st.setString(2, password);         int num = st.executeUpdate(sql);                     if(num>0){                      System.out.println("插入成功！！");              }                    DbUtils.release(conn, st, rs); } public static void main(String args[]) throws Exception{ …… 类名.insert("hello","89790"); …… } }+----------+--------------+------+-----+---------+-------+| Field    | Type         | Null | Key | Default | Extra |+----------+--------------+------+-----+---------+-------+| userID   | int(11)      | YES  |     | NULL    |       || name     | varchar(255) | YES  |     | NULL    |       || sex      | varchar(255) | YES  |     | NULL    |       || birthday | date         | YES  |     | NULL    |       || password | varchar(255) | YES  |     | NULL    |       |+----------+--------------+------+-----+---------+-------+一直报错，但是不知道是怎么错了。求教 orzException in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?,?)' at line 1 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) at com.mysql.jdbc.Util.getInstance(Util.java:387) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:939) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2547) at com.mysql.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1541) at com.mysql.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2605) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1469) at dao.IUserDao.insert(IUserDao.java:107) at dao.IUserDao.main(IUserDao.java:120)

Answer 1

st = conn.prepareStatement(sql);

  int num = st.executeUpdate(sql);改为 int num =st.executeUpdate();