Question

这让我很难过。我使用循环遍历数组，然后使用ifs / else查找是否符合条件。但是，即使正在执行if，else语句也会继续执行。可能是一些非常基本的东西。我需要在用户输入流派时检查if语句两次，以及数组中的项目也符合该流派。

欢呼声

  for (int i = 0; i < movies.length; i++)
  {
     //RentalMovie movie = movies[i];

     if(movies[i].getMovieGenre().equalsIgnoreCase("action") && movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";
     }
     else if(movies[i].getMovieGenre().equalsIgnoreCase("childrens") && movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";         
     }
     else if (movies[i].getMovieGenre().equalsIgnoreCase("drama") && movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";            
     }
     else
     {
        genreList += "- No rental movies were found for the genre: " + genreID; 
     } 

  }

Answer 1

可能发生的是if语句未正确评估。这就是我想要的：

  for (int i = 0; i < movies.length; i++)
  {
     //RentalMovie movie = movies[i];

     if(movies[i].getMovieGenre().equalsIgnoreCase("action") && movies[i].getMovieGenreID().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";
     }
     else if(movies[i].getMovieGenre().equalsIgnoreCase("childrens") && movies[i].getMovieGenreID().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";         
     }
     else if (movies[i].getMovieGenre().equalsIgnoreCase("drama") && movies[i].getMovieGenreID().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";            
     }
     else
     {
        genreList += "- No rental movies were found for the genre: " + genreID; 
     } 

  }

我要尝试的另一件事是摆脱一些代码，即：

 for (int i = 0; i < movies.length; i++)
  {
     //RentalMovie movie = movies[i];

     if(movies[i].getMovieGenre().equalsIgnoreCase("action"))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";
     }
     else if(movies[i].getMovieGenre().equalsIgnoreCase("childrens"))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";         
     }
     else if (movies[i].getMovieGenre().equalsIgnoreCase("drama"))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";            
     }
     else
     {
        genreList += "- No rental movies were found for the genres action, childrens, or drama -";
     } 

  }

我建议的第三件事就是试试这个：

  for (int i = 0; i < movies.length; i++)
  {
     //RentalMovie movie = movies[i];

     if(movies[i].getMovieGenre().equalsIgnoreCase("action") || movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";
     }
     else if(movies[i].getMovieGenre().equalsIgnoreCase("childrens"))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";         
     }
     else if (movies[i].getMovieGenre().equalsIgnoreCase("drama"))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";            
     }
     else
     {
        genreList += "- No rental movies were found for the genre: " + genreID; 
     } 

  }

Answer 2

我怀疑你的意思是你在数组中有一些符合你搜索条件的条目，而其他条目没有。对于每个匹配，正在执行相应的if子句，但对于每个不匹配，else正在执行。

由于else中的操作是添加一条消息，表明找到了 no 匹配项，因此您可能不希望每次找到一个不匹配项时添加该匹配项。相反，如果没有找到任何匹配，你想在循环之后执行一次。这可能看起来像：

String genreList = "";

for (int i = 0; i < movies.length; i++)
  {
     if(movies[i].getMovieGenre().equalsIgnoreCase("action") && movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";
     }
     else if(movies[i].getMovieGenre().equalsIgnoreCase("childrens") && movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";         
     }
     else if (movies[i].getMovieGenre().equalsIgnoreCase("drama") && movies[i].getMovieGenre().equalsIgnoreCase(genreID))
     {
        genreList += movies[i].getMovieID() + " - " + movies[i].getMovieTitle() + "[" + movies[i].getMediaType() + "]\n";            
     }
     else
     {
     } 

  }

if (genreList.equals(""))
{
  genreList = "No rental movies were found for the genre: " + genreID;
}

P.S。我完全不明白为什么你在接受它之前检查每部电影的类型genreID和硬编码值。列表中是否存在其他类型，但您不希望用户能够搜索？这是它似乎有意义的唯一方式，但这似乎不是一个非常明智的要求。

Answer 3

尝试使用调试器逐步执行它，您可以随时观察变量的状态。

Java - 循环语句中的其他内容继续执行

3 个答案: