Question

public static int howMany(String FileName)
{
    BufferedReader br = null;

    try
    {
        FileInputStream fis = new FileInputStream(FileName);
        DataInputStream dis = new DataInputStream(fis);
        br = new BufferedReader(new InputStreamReader(dis));
    }
    catch (FileNotFoundException e)
    {
        System.out.print("FILE DOESN'T EXIST");
    }
    finally
    {
        fis.close();
        dis.close();
        br.close();
    }


    String input;
    int count = 0;

    try
    {

        while ((input = br.readLine()) != null)
        {
            count++;
        }

    }
    catch (IOException e) 
    {
        System.out.print("I/O STREAM EXCEPTION");
    }


    return count;
}

由于某种原因，我无法关闭任何I / O对象。即使我导入了所有的I / O库（导入java.io. *;）并启动了所有对象，fis.close（），dis.close（），br.close（）都给我找不到符号。

Answer 1

 BufferedReader br = null;
 FileInputStream fis =null;
 DataInputStream dis null;
 try {
     fis = new FileInputStream(FileName);
     dis = new DataInputStream(fis);
     br = new BufferedReader(new InputStreamReader(dis));
 }

将它们从try block中取出，以便你的finally块可以看到变量。

Answer 2

您必须在try块之外声明所有流，否则它们将无法在finally块中显示：

FileInputStream fis = null;
DataInputStream dis = null;
BufferedReader br = null;

或者，您可以使用Java 7的新try-with-resources语法来自动关闭资源。

Answer 3

你的对象在你的块中是空的

FileInputStream fis =null;
DataInputStream dis null;

在块之外定义它们

try{

    fis = new FileInputStream(FileName);
    dis = new DataInputStream(fis);

   }

Answer 4

你已经将fis限定在try块中，所以决赛并不知道它在那里。尝试：

FileInputStream fis;
DataInputStream dis;
try
    {
        fis = new FileInputStream(FileName);
        dis = new DataInputStream(fis);
        br = new BufferedReader(new InputStreamReader(dis));
    }

Answer 5

试试这个：

BufferedReader br = null;
FileInputStream fis = null;
DataInputStream dis = null;
try
{
    fis = new FileInputStream(FileName);
    dis = new DataInputStream(fis);
    br = new BufferedReader(new InputStreamReader(dis));
}

尝试关闭I / O对象时“找不到符号”

5 个答案: