SQLite general getEntry(.)函数

Question

我在一个Java上编写了一个SQLite“Actionhandler”，您可以在其中创建/删除表，并在这些表中添加/更新/获取/删除条目。

表的一般创建/删除和条目的添加可以正常工作，但是现在我想要使getEntry(...)函数。

public void getEntry(String table, String[] ident){
    try{
        stmt = conn.createStatement();
        String exec = "SELECT " + ident[0] + " FROM " + table;
        if(!ident[1].isEmpty()){
            exec += " WHERE(" + ident[1] + ");";
        }else{
            exec += ";";
        }
        ResultSet res = stmt.executeQuery(exec);
        while(res.next()){
            System.out.println(res.getInt("uid"));
            System.out.println(res.getString("uname"));
            System.out.println(res.getString("pwd"));
            System.out.println(res.getString("mail"));
            System.out.println(res.getInt("rank"));
            System.out.println(res.getInt("coins"));
            System.out.println(res.getString("stg"));
        }
        res.close();
        stmt.close();
    }catch(Exception e){
        e.printStackTrace();
    }
}

当然，这很管用！但是我不想System.out.println(...)所有的数据，我想把它还给main(...)函数，它叫getEntry(...)函数，这样它就可以处理这些数据了。如何返回此函数的res数据？

Answer 1

您可以以ResultSet的形式返回函数：

public ResultSet getEntry(String table, String[] ident){
try{
        stmt = conn.createStatement();
        String exec = "SELECT " + ident[0] + " FROM " + table;
        if(!ident[1].isEmpty()){
            exec += " WHERE(" + ident[1] + ");";
        }else{
            exec += ";";
        }
        ResultSet res = stmt.executeQuery(exec);
       /* while(res.next()){
            System.out.println(res.getInt("uid"));
            System.out.println(res.getString("uname"));
            System.out.println(res.getString("pwd"));
            System.out.println(res.getString("mail"));
            System.out.println(res.getInt("rank"));
            System.out.println(res.getInt("coins"));
            System.out.println(res.getString("stg"));
        }res.close();
        stmt.close();*/

return res;
    }catch(Exception e){
        e.printStackTrace();
    }
}

然后在总体上您可以处理ResultSet

 public static void main (String args []){

  YourClass yourInstance = new YourClass ();

ResultSet tempResultSet = yourInstance.getEntry();
   while( tempResultSet .next() ){
   System.out.println(res.getInt("uid"));
        System.out.println(res.getString("uname"));
        System.out.println(res.getString("pwd"));
        System.out.println(res.getString("mail"));
        System.out.println(res.getInt("rank"));
        System.out.println(res.getInt("coins"));
        System.out.println(res.getString("stg"));
  }

  yourInstance .stmt.close() ; // this is assuming stmt is public
  yourInstance.tempResultSet.close()

}

如果有一个类似于stmt的方法返回getStmt()，那么就用yourInstance.getStmt().close()关闭它