你可以使用下面的代码在文件中追加内容:

 String fileName="/home/shriram/Desktop/Images/"+"test.txt";
  FileWriter fw=new FileWriter(fileName,true);    
  fw.write("here will be you content to insert or append in file");    
  fw.close(); 
  FileWriter fw1=new FileWriter(fileName,true);    
 fw1.write("another content will be here to be append in the same file");    
 fw1.close(); 

这里使用try/catch块的所有答案不都应该在finally块中包含.close()块吗?

有标记的答案示例:

PrintWriter out = null;
try {
    out = new PrintWriter(new BufferedWriter(new FileWriter("writePath", true)));
    out.println("the text");
} catch (IOException e) {
    System.err.println(e);
} finally {
    if (out != null) {
        out.close();
    }
} 

此外，从Java 7开始，您可以使用try-with-resources语句。关闭已声明的资源时不需要finally块，因为它是自动处理的，而且不太详细:

try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("writePath", true)))) {
    out.println("the text");
} catch (IOException e) {
    System.err.println(e);
}

使用java.nio.Files和java.nio.file.StandardOpenOption

    PrintWriter out = null;
    BufferedWriter bufWriter;

    try{
        bufWriter =
            Files.newBufferedWriter(
                Paths.get("log.txt"),
                Charset.forName("UTF8"),
                StandardOpenOption.WRITE, 
                StandardOpenOption.APPEND,
                StandardOpenOption.CREATE);
        out = new PrintWriter(bufWriter, true);
    }catch(IOException e){
        //Oh, no! Failed to create PrintWriter
    }

    //After successful creation of PrintWriter
    out.println("Text to be appended");

    //After done writing, remember to close!
    out.close();

这将使用Files创建一个BufferedWriter，它接受StandardOpenOption参数，并从结果BufferedWriter创建一个自动刷新的PrintWriter。然后可以调用PrintWriter的println()方法来写入文件。

这段代码中使用的StandardOpenOption参数:打开文件进行写入，仅追加到文件中，并在文件不存在时创建文件。

路径。get("path here")可以用new File("path here"). topath()代替。 和字符集。forName(“字符集名称”)可以修改以适应所需的字符集。

在项目的任何地方创建一个函数，并在任何需要的地方简单地调用该函数。

伙计们，你们要记住，你们调用的是活动线程，而不是异步调用，因为它可能需要5到10页才能完成。 为什么不花更多的时间在你的项目上，忘掉已经写好的东西。 正确

    //Adding a static modifier would make this accessible anywhere in your app

    public Logger getLogger()
    {
       return java.util.logging.Logger.getLogger("MyLogFileName");
    }
    //call the method anywhere and append what you want to log 
    //Logger class will take care of putting timestamps for you
    //plus the are ansychronously done so more of the 
    //processing power will go into your application

    //from inside a function body in the same class ...{...

    getLogger().log(Level.INFO,"the text you want to append");

    ...}...
    /*********log file resides in server root log files********/

三行代码，实际上是两行，因为第三行实际上是追加文本。: P

最好使用try-with-resources，而不是java 7之前的所有业务

static void appendStringToFile(Path file, String s) throws IOException  {
    try (BufferedWriter out = Files.newBufferedWriter(file, StandardCharsets.UTF_8, StandardOpenOption.APPEND)) {
        out.append(s);
        out.newLine();
    }
}

    String str;
    String path = "C:/Users/...the path..../iin.txt"; // you can input also..i created this way :P

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter pw = new PrintWriter(new FileWriter(path, true));

    try 
    {
       while(true)
        {
            System.out.println("Enter the text : ");
            str = br.readLine();
            if(str.equalsIgnoreCase("exit"))
                break;
            else
                pw.println(str);
        }
    } 
    catch (Exception e) 
    {
        //oh noes!
    }
    finally
    {
        pw.close();         
    }

这将达到你的目的。