Question

我有一个valet类方法，应该将小时工资写入文件：

public void hourlyOverall() throws FileNotFoundException
{
    PrintWriter out = new PrintWriter("wage info");
    new FileOutputStream("wage info", true);
    hourlyOverall = tips / hours + hourlyWage;
    out.println(hourlyOverall);
}

但是，当我在valet.hourlyOverall()方法中运行main时，会创建“工资信息”文件，但不会写入任何内容。我做错了什么？

Answer 1

首先使用try-catch进行Exception处理，然后在finally块中关闭OutputStream

out.flush();

像这样的事情

try {
        PrintWriter out = new PrintWriter("wage info");
        hourlyOverall=tips/hours+hourlyWage;
        out.println(hourlyOverall);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    finally {
        out.flush();
    }

Answer 2

我认为这是解决问题的另一种方法，但使用其他类

public class valet {
    public static void main(String []args)throws IOException
    {
        try
        {
            hourlyOverall()
        }
        catch(IOException ex)
        {
            System.out.println(ex+"\n");
        }
    }

    public void hourlyOverall() throws IOException
    {
        FileWriter out = new FileWriter("wage info");
        hourlyOverall=tips/hours+hourlyWage;
        out.write(hourlyOverall+"\r\n");
        out.close();
    }
}

Answer 3

您可能不应声明匿名FileOutputStream并且您应该关闭PrintWriter，

PrintWriter out=new PrintWriter("wage info");
// new FileOutputStream("wage info",true);
hourlyOverall=tips/hours+hourlyWage;
out.println(hourlyOverall);
out.close();                             // <-- like that

Answer 4

做这样的事情（如果java7或更高版本）：

 public void hourlyOverall()
    {
        try (PrintWriter out=new PrintWriter("wage info")){
           //new FileOutputStream("wage info",true);
           hourlyOverall=tips/hours+hourlyWage;
           out.println(hourlyOverall);
        }catch (FileNotFoundException e) {
           e.printStackTrace();
        }
    }

http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html

使用类方法java将文本输出到文件

4 个答案: