如何使用Java

Question

try 
{ 
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
    con1=DriverManager.getConnection("jdbc:odbc:MyDatabase"); 
    st1=con1.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); 
    System.out.println("Connect database in BallMoves1.java ......."); 
    /*the below line giving error*/ 
    rs1 = st1.executeQuery("insert into highscore" + " (score) " + "values('"+score+"')"); 
    System.out.println("Score is inserted.."); 
    System.out.println("Score......."+score); 
}catch(Exception e){ e.printStackTrace();} 

/*highscore is table and attributes of table are (sid,score). 

所產生的誤差插入在MS Access值爲：

Connect database in BallMoves1.java ....... 
java.sql.SQLException: No ResultSet was produced 
    at sun.jdbc.odbc.JdbcOdbcStatement.executeQuery(JdbcOdbcStatement.java:258) 
    at BallMoves1.move(BallMoves1.java:378) 
    at BallMoves1.run(BallMoves1.java:223) 
    at java.lang.Thread.run(Thread.java:744)*/ 

Answer 1

你打電話executeQuery的東西，不是一個查詢。但是，而不是調用execute用相同的SQL，你應該使用一個PreparedStatement：

String sql = "insert into highscore (score) values (?)"; 
try (Connection conn = DriverManager.getConnection("jdbc:odbc:MyDatabase"); 
    PreparedStatement statement = conn.prepareStatement(sql)) { 
    statement.setInt(1, score); 
    statement.executeUpdate(); 
    conn.commit(); 
} 

始終使用參數化的SQL，而不是直接將值插入SQL - 保護您免受SQL注入攻擊，轉換錯誤，以及難以閱讀的代碼。

使用try-with-resources語句（如我一樣）自動關閉塊末尾的語句和連接。