PrintWriter和FileWriter类之间的区别 [英] Difference between PrintWriter and FileWriter class

问题描述

 尝试{
 
文件file = new File（write.txt）; 
 FileWriter writer = new FileWriter（file）; 
 
 PrintWriter printWriter = new PrintWriter（writer）; 
 printWriter.println（pqr）; 
 printWriter.println（jkl）; 
 printWriter.close（）; 
 
 PrintWriter printWriter = new PrintWriter（file）; 
 printWriter.println（abc）; 
 printWriter.println（xyz）; 
 printWriter.close（）; 
} 
  

我不明白这两种方式有什么区别。
在这种情况下，我应该使用printWriter和fileWriter。

解决方案

尽管这两个内部使用FileOutputStream，不同之处在于PrintWriter提供了一些额外的格式化方法，如println和printf。
$ b $ p

代码片段：

  public PrintWriter（File file）引发FileNotFoundException {
 this（new BufferedWriter（new OutputStreamWriter（new FileOutputStream（file））），
 false）; 
 
 
 $ b public FileWriter（File file）throws IOException {
 super（new FileOutputStream（file））; 
 
 
 
 $ b $ p 
 
 
 $ b 主要区别： ol> 
 
如果发生任何IO故障，FileWriter将抛出IOException。
 
没有一个PrintWriter方法抛出IOException，而是设置了一个布尔标志，可以使用checkError （）。
 
 
写入数据的每个字节后，PrintWriter会自动调用flush。在FileWriter的情况下，调用者必须照顾调用flush。
 
 
 
try{

    File file = new File("write.txt");
    FileWriter writer = new FileWriter(file);

    PrintWriter printWriter = new PrintWriter(writer);
    printWriter.println("pqr");
    printWriter.println("jkl");
    printWriter.close();

    PrintWriter printWriter = new PrintWriter(file);
    printWriter.println("abc");
    printWriter.println("xyz");
    printWriter.close();
}
I don't understand what is difference bet'n these two way.
In which scenario i should use printWriter and fileWriter.
解决方案
Although both of these internally uses a FileOutputStream , the main difference is that PrintWriter offers some additional methods for formatting like println and printf.

code snippets:
public PrintWriter(File file) throws FileNotFoundException {
     this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file))),
     false);
}


public FileWriter(File file) throws IOException {
       super(new FileOutputStream(file));
}
Major Differences : 

FileWriter throws IOException in case of any IO failure.
None of the PrintWriter methods throws IOException, instead they set a boolean flag which can be obtained using checkError().
PrintWriter automatically invokes flush after every byte of data is written. In case of FileWriter, caller has to take care of invoking flush.


                        
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