Question

我参与Java项目并编写SQLite＆＃34; Actionhandler-Class＆＃34;您可以在这些表中创建/删除表并添加/更新/获取/删除条目。

表的一般创建/删除和添加条目工作正常，但现在我想创建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();
    }
}

这当然有效！但我不希望System.out.println(...)所有数据，我想将其返回给调用main(...)函数的getEntry(...)函数，以便它可以使用此数据。如何提供此函数的res数据？

Answer 1

您可以将该功能改为ResultSet：

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main中，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()

}

如果有一个方法返回stmt假设getStmt()，那么请用yourInstance.getStmt().close()

关闭它

SQLite一般的getEntry（...）函数

1 个答案: