try catch finally的应用

 

在使用try catch finally时，有时会出现upexcepted exception ... 这里就是你的try块写得有问题了。可能是由于需要

try catch的地方，你没有使用。下面的一个是正常的。

    private void QuearyDB(String strSQL)
    ...{
        Connection con = db.getConn ();
        Statement stmt = null;
        ResultSet rs = null;
        try
        ...{
            stmt = con.createStatement();

            String querySql = strSQL;

            /** *//** 执行查询操作*/
            rs = stmt.executeQuery(querySql);

            while(rs.next ())
            ...{
                /** *//** 关键词 */
                String keyWord = rs.getString (KEY_WORD);
                /** *//** 出现次数 */
                int    count   = rs.getInt (APPEAR_COUNT);
                
                double possibleOne = (double)count/ (double)GoodAppearCountSum;

                /** *//** 获取另外一个表的相关数据 */
                double possibleTwo =GetAnotherPossible(keyWord);
                
                double probility = possibleOne/(possibleOne+possibleTwo);
                
                InsertPossible(keyWord,probility);

            }

        }
        catch (SQLException e) 
        ...{
            e.getStackTrace ();
        }              
        finally
        ...{
            if(rs!=null)
            ...{
                try
                ...{
                    rs.close ();
                }
                catch(Exception e)
                ...{
                    e.getStackTrace ();
                }
                
            }
                        
            if(stmt!=null)
            ...{
                try
                ...{
                    stmt.close ();
                }
                catch(Exception e)
                ...{
                    e.getStackTrace ();
                }
                
            }
            
        }
    }