Java读取文件，如果不存在的话创建它 [英] Java read a file, if it doesn't exist create it

问题描述

这里是我的代码

  public String path; 
 public String fileName; 
 public static void readData（）throws IOException {
 try {
 path =myPath
 fileName =myFileName; 
 fstream = new FileInputStream（path + fileName）; 
 br = new BufferedReader（new InputStreamReader（fstream））; 
 //做些什么... // 
} 
 br.close（）; 
} catch（FileNotFoundException ex）{
 JOptionPane.showMessageDialog（null，Reading file error）; 
 Logger.getLogger（LeggiDaFile.class.getName（））。log（Level.SEVERE，null，ex）; 
 
 
 
 
 $ b 
我想知道如何检查fstream是否存在。如果它不存在，则必须创建一个新文件。我该怎么做？ 
谢谢 
 
解决方案
这是一个可能的解决方案：
 
 
 public static void readData（）throws IOException 
 {
 File file = new File（path，filename）; $！
 $ b if（！file.isFile（）&&！file.createNewFile（））
 {
抛出新的IOException（Error new file：+ file。 getAbsolutePath（））; 
} 
 
 BufferedReader r = new BufferedReader（new FileReader（file））; 
 
 try 
 {
 //读取数据
} finally 
 {
 r.close（）; 
} 
} 
  
 
here's my code
public String path;
public String fileName;
public static void readData() throws IOException{
    try {
        path="myPath"
        fileName="myFileName";
        fstream = new FileInputStream(path+fileName);
        br = new BufferedReader(new InputStreamReader(fstream));
        //do something...//
        }
        br.close();
    } catch (FileNotFoundException ex) {
        JOptionPane.showMessageDialog(null, "Reading file error");
        Logger.getLogger(LeggiDaFile.class.getName()).log(Level.SEVERE, null, ex);
    }
}
I wanted to know how to check if the fstream exists. If it doesn't exist, a new file has to be created. How can I do this?
Thanks
解决方案
Here's a possible solution:
public static void readData() throws IOException
{
    File file = new File(path, filename);

    if (!file.isFile() && !file.createNewFile())
    {
        throw new IOException("Error creating new file: " + file.getAbsolutePath());
    }

    BufferedReader r = new BufferedReader(new FileReader(file));

    try 
    {
        // read data
    }finally
    {
        r.close();
    }
}


                        
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