Question

数组存储了所有信息，我觉得这个程序真的很接近工作。我知道它不整洁，我会立即清理它！问题在底部。

 public class FoodFacts
{
     private static BufferedReader textIn;
     private static BufferedReader foodFacts;
             static int numberOfLines = 0;
               static  int NUM_COL = 7;
            static int NUM_ROW = 961;
             static String [][] foodArray = new String[NUM_ROW][NUM_COL];
      public static String  fact;
    // Make a random number to pull a line
    static Random r = new Random();




    public static void main(String[] args)
        {
            try 
            {   

                textIn = new BufferedReader(new InputStreamReader(System.in));
                foodFacts= new BufferedReader(new FileReader("foodfacts.csv"));
                Scanner factFile = new Scanner(foodFacts);
                List<String> facts = new ArrayList<String>();

                //  System.out.println("Printing out your array!");
                while ( factFile.hasNextLine()){
                 fact = factFile.nextLine();
                 StringTokenizer st2 = new StringTokenizer(fact, ",")    ;

               while (st2.hasMoreElements()){
                  for ( int j = 0; j < NUM_COL ; j++) {
                    foodArray [numberOfLines][j]= st2.nextToken();  
                    //System.out.println("Foodarray at " + "  " + numberOfLines + " is " +foodArray[numberOfLines][j]);
                   }
                    }  
                     numberOfLines++;
                  }

System.out.println("Please type in the food you wish to know about.");
                String request; //user input 
                request = textIn.readLine();
                System.out.println ("You requested" + request);

问题从这里开始！

for ( int i = 0; i < NUM_ROW ; i++)
                    {
if ( foodArray[i][0] == request)
                            for ( int j = 0 ; j < NUM_COL ; j++ )
                        System.out.println ( foodArray[i][j] ); //never prints anything
                        }  

                  }
                    catch (IOException e)
                    {
                    System.out.println ("Error, problem reading text file!");
                    e.printStackTrace();
                    }

             }
  }

我正在尝试在foodArray [6] [0]匹配输入All-Bran Cereal的终端中测试它

Answer 1

在上一个for循环中，您使用==中的if construct运算符比较字符串，这会给您不正确的结果，因为==会比较字符串引用，这将是不同的，因为两个引用都指向不同的字符串对象。

使用equals方法比较字符串内容： -

if (foodArray[i][0].equals(request))

如果您想比较他们的equals，则应始终对object content使用{{1}}方法。

查看此信息： - How do I Compare strings in Java了解详情。

从用户输入的字符串和String [] []的第一列中检索匹配

1 个答案: