狂暈，code了一下午才搞定小小的問題

package oa;
import java.sql.*;

public class DBConn {
String sDBDriver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
String sConnStr = "jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=office";
Connection conn = null;
ResultSet rs = null;
int rs2=0;

public DBConn()
{
try {
     Class.forName(sDBDriver);
     conn = DriverManager.getConnection(sConnStr,"center","center");
    }
catch(java.lang.ClassNotFoundException e)
    {
    System.err.println("faq(): " + e.getMessage());
    }
catch(SQLException ex)
    {
    System.err.println("aq.executeQuery: " + ex.getMessage());
    }
}

public int executeUpdate(String sql)
 {
  try
    {
    Statement stmt = conn.createStatement();
 rs2=stmt.executeUpdate(sql);

    }
  catch(SQLException ex)
    {
    System.err.println("aq.executeQuery: " + ex.getMessage());
    }
  return rs2;
 

 }
public ResultSet executeQuery(String sql)
{
  rs = null;
  try
    {
    Statement stmt = conn.createStatement();
    rs = stmt.executeQuery(sql);

    }
  catch(SQLException ex)
    {
    System.err.println("aq.executeQuery: " + ex.getMessage());
    }
 
  return rs;

}

}

調試了一下午
剛開始調executeQuery
成功後調試executeUpdate
可是怎麼都不行
最後baidu
java.lang.NoSuchMethodError executeUpdate

結果問題是


有可能是TOMCAT在你更改以後沒有檢測到類文件的更新,把WORKS目錄下的東西都刪除,重新啓動服務器試試.