java连oracle，可以连入，但插入数据无法成功
package Ceshi;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Ceshi {


private static Statement dbstate;
private Connection conn;
public Ceshi ()
{
dbstate=null;
conn = null;
}
public Connection Conn1()
{
Connection conn = null;
try {
try {
Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

String url="jdbc:oracle:thin:@localhost:1521:orcl"; //orcl为数据库的SID

String user="system";

String password="orcl123";

conn= DriverManager.getConnection(url,user,password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}

return conn;
}

public boolean dbInsert(String name,String type,String data,String time,String intro1,String intro2)
{
/**
** 对数据库表进行插入操作
* * @param hm
* * @return bool值，成功返回true，失败返回false
* */
String CNAMEstr=name;
String CTYPEstr=type;
String CDATAstr=data;
String CTIMEstr=time;
String USER_INTRO1str=intro1;
String USER_INTRO2str=intro2;
Conn1();
String sql = "";
boolean insertResult = false;
sql += "insert into CHAT values" + "(" + "chat_seq.nextval"+",'"+ CNAMEstr+"','"+CTYPEstr+"','"+CDATAstr+"','"+CTIMEstr+"','"+USER_INTRO1str+"','"+USER_INTRO2str+"')";
try
{
dbstate.executeUpdate(sql);
System.out.println("Sql1 = " + sql);
insertResult = true;
System.out.println("Sql2 = " + sql);
}
catch(Exception e)
{
System.out.println("Sql3= " + sql);
}
if (insertResult)
return true;
else
return false;

}


public static void main(String[] args) {
// TODO Auto-generated method stub

Ceshi obj=new Ceshi();
Connection con=obj.Conn1();
if(con==null)
System.out.print("连接失败");
else
System.out.print("连接成功");

boolean in = obj.dbInsert("服务器","123","123","123",null,null); //—>>>插入
if (in)
System.out.println("insert OK" );
else
System.out.println("insert error! ");

}

}

执行结果：

Sql3= insert into CHAT (CID,CNAME,CTYPE,CDATA,CTIME,USER_INTRO1,USER_INTRO2) values(chat_seq.nextval,'服务器','1001','uuu','2012-10-23 09:20:29:0187','null','null')
insert error!

一直无法插入成功！

求原因？
[解决办法]
把异常打印出来啊，看看具体什么错误。
CTIME字段是timestamp类型？如果是CTIME字段的错误，
'2012-10-23 09:20:29:0187'
改成
to_timestamp('2012-10-23 09:20:29:0187','yyyy-mm-dd hh24:mi:ss:ff')
[解决办法]
把异常打出来看看，看看具体的异常就好分析了。估计是数据类型的问题
[解决办法]
你看看你有插入权限没有？
[解决办法]

private static Statement dbstate;  

public Ceshi ()
{
dbstate=null;
conn = null;
}

dbstate.executeUpdate(sql);  

如果你没漏掉代码，那你从头到尾都用一个null来执行SQL。

dbstate = con.createStatement();