blocks|key|127030|text|我认为你的期望和现实不匹配(但它们什么时候会匹配；)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|127031|基本上，您认为文件写入的位置和实际写入文件的位置并不相等(嗯，也许我应该写一个if语句；)|offset|length|style|CODE|127032|public+class+TestWriteFile+{

++++public+static+void+main(String[]+args)+{
++++++++BufferedWriter+writer+=+null;
++++++++try+{
++++++++++++//create+a+temporary+file
++++++++++++String+timeLog+=+new+SimpleDateFormat("yyyyMMdd_HHmmss").format(Calendar.getInstance().getTime());
++++++++++++File+logFile+=+new+File(timeLog);

++++++++++++//+This+will+output+the+full+path+where+the+file+will+be+written+to...
++++++++++++System.out.println(logFile.getCanonicalPath());

++++++++++++writer+=+new+BufferedWriter(new+FileWriter(logFile));
++++++++++++writer.write("Hello+world!");
++++++++}+catch+(Exception+e)+{
++++++++++++e.printStackTrace();
++++++++}+finally+{
++++++++++++try+{
++++++++++++++++//+Close+the+writer+regardless+of+what+happens...
++++++++++++++++writer.close();
++++++++++++}+catch+(Exception+e)+{
++++++++++++}
++++++++}
++++}
}|code-block|syntax|javascript|127033|还要注意，您的示例将覆盖任何现有文件。如果要将文本附加到文件，则应改为执行以下操作：|127034|writer+=+new+BufferedWriter(new+FileWriter(logFile,+true));|127035|entityMap^0|0|13|2|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|W|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|Y|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

I think your expectations and reality don't match (but when do they ever ;))

Basically, where you think the file is written and where the file is actually written are not equal (hmmm, perhaps I should write an <code>if</code> statement ;))

<pre><code>public class TestWriteFile {

 public static void main(String[] args) {
 BufferedWriter writer = null;
 try {
 //create a temporary file
 String timeLog = new SimpleDateFormat("yyyyMMdd_HHmmss").format(Calendar.getInstance().getTime());
 File logFile = new File(timeLog);

 // This will output the full path where the file will be written to...
 System.out.println(logFile.getCanonicalPath());

 writer = new BufferedWriter(new FileWriter(logFile));
 writer.write("Hello world!");
 } catch (Exception e) {
 e.printStackTrace();
 } finally {
 try {
 // Close the writer regardless of what happens...
 writer.close();
 } catch (Exception e) {
 }
 }
 }
}
</code></pre>

Also note that your example will overwrite any existing files. If you want to append the text to the file you should do the following instead:

<pre><code>writer = new BufferedWriter(new FileWriter(logFile, true));
</code></pre>

blocks|key|344777|text|我想对MadProgrammer的回答补充一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344778|在多行写入的情况下，当执行命令时|344779|writer.write(string);|code-block|syntax|javascript|344780|可以注意到在写入的文件中省略或跳过换行符，即使它们在调试期间出现或者如果相同的文本被打印到终端上，|344781|System.out.println("\n");|344782|因此，整个文本作为一大块文本出现，这在大多数情况下是不可取的。换行符可以依赖于平台，因此最好使用以下命令从java系统属性中获取此字符|344783|String+newline+=+System.getProperty("line.separator");|344784|然后使用newline变量而不是"\n“。这将以您想要的方式获得输出。|344785|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

I would like to add a bit more to MadProgrammer's Answer.

In case of multiple line writing, when executing the command 

<pre><code>writer.write(string);
</code></pre>

one may notice that the newline characters are omitted or skipped in the written file even though they appear during debugging or if the same text is printed onto the terminal with,

<pre><code>System.out.println("\n");
</code></pre>

Thus, the whole text comes as one big chunk of text which is undesirable in most cases.
The newline character can be dependent on the platform, so it is better to get this character from the java system properties using

<pre><code>String newline = System.getProperty("line.separator");
</code></pre>

and then using the newline variable instead of "\n". This will get the output in the way you want it.

blocks|key|344820|text|在java+7中现在可以做|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344821|try(BufferedWriter+w+=+....)
{
++w.write(...);
}
catch(IOException)
{
}|code-block|syntax|javascript|344822|并且w.close将会自动完成|344823|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

In java 7 can now do

<pre><code>try(BufferedWriter w = ....)
{
 w.write(...);
}
catch(IOException)
{
}
</code></pre>

and w.close will be done automatically

blocks|key|344848|text|您可以尝试使用Java库。FileUtils，它有很多写文件的函数。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|344849|entityMap|0|LINK|mutability|MUTABLE|url|http://commons.apache.org/proper/commons-io/apidocs/org/apache/commons/io/FileUtils.html^0|D|9|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

You can try a Java Library. <a href="http://commons.apache.org/proper/commons-io/apidocs/org/apache/commons/io/FileUtils.html" rel="nofollow">FileUtils</a>, It has many functions that write to Files.

blocks|key|127159|text|它不是在创建文件，因为您从未实际创建过该文件。你为它做了一个对象。创建实例不会创建文件。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|127160|File+newFile+=+new+File("directory",+"fileName.txt");|code-block|syntax|javascript|127161|你可以这样做来创建一个文件：|127162|newFile.createNewFile();|127163|您可以执行以下操作来创建文件夹：|127164|newFile.mkdir();|127165|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

It's not creating a file because you never actually created the file. You made an object for it. Creating an instance doesn't create the file.

<pre><code>File newFile = new File("directory", "fileName.txt");
</code></pre>

You can do this to make a file:

<pre><code>newFile.createNewFile();
</code></pre>

You can do this to make a folder:

<pre><code>newFile.mkdir();
</code></pre>

blocks|key|344948|text|这对我来说很管用。确保在timeLog旁边附加了".txt“。我在一个用Netbeans打开的简单程序中使用它，它将程序写在主文件夹(+builder和src文件夹所在的位置)中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344949|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

It does work with me. Make sure that you append ".txt" next to timeLog. I used it in a simple program opened with Netbeans and it writes the program in the main folder (where builder and src folders are).

blocks|key|127269|text|使用java+8+LocalDateTime和java+7+try-with语句：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|127270|public+class+WriteFile+{

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

++++++++String+timeLog+=+DateTimeFormatter.ofPattern("yyyyMMdd_HHmmss").format(LocalDateTime.now());
++++++++File+logFile+=+new+File(timeLog);

++++++++try+(BufferedWriter+bw+=+new+BufferedWriter(new+FileWriter(logFile)))+
++++++++{
++++++++++++System.out.println("File+was+written+to:+"++%2B+logFile.getCanonicalPath());
++++++++++++bw.write("Hello+world!");
++++++++}+
++++++++catch+(IOException+e)+
++++++++{
++++++++++++e.printStackTrace();
++++++++}
++++}
}|code-block|syntax|javascript|127271|entityMap^0|9|D|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Using java 8 <code>LocalDateTime</code> and java 7 try-with statement:

<pre><code>public class WriteFile {

 public static void main(String[] args) {

 String timeLog = DateTimeFormatter.ofPattern("yyyyMMdd_HHmmss").format(LocalDateTime.now());
 File logFile = new File(timeLog);

 try (BufferedWriter bw = new BufferedWriter(new FileWriter(logFile))) 
 {
 System.out.println("File was written to: " + logFile.getCanonicalPath());
 bw.write("Hello world!");
 } 
 catch (IOException e) 
 {
 e.printStackTrace();
 }
 }
}
</code></pre>

The following code does not produce a file (I can't see the file anywhere).
What is missing?

<pre><code>try {
 //create a temporary file
 String timeLog = new SimpleDateFormat("yyyyMMdd_HHmmss").format(
 Calendar.getInstance().getTime());
 File logFile=new File(timeLog);

 BufferedWriter writer = new BufferedWriter(new FileWriter(logFile));
 writer.write (string);

 //Close writer
 writer.close();
} catch(Exception e) {
 e.printStackTrace();
}
</code></pre>

How to Write text file Java

Java

下面的代码没有生成文件(我在任何地方都看不到该文件)。遗漏了什么？try {    //create a temporary file    String timeLog = new SimpleDateFormat("yyyyMMdd_HHmmss").format(        Calendar.getInsta...

问如何编写Java文本文件
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