最好在finally块中关闭writer/outputstream，以防发生意外

finally{
   if(writer != null){
     try{
        writer.flush();
        writer.close();
     }
     catch(IOException ioe){
         ioe.printStackTrace();
     }
   }
}

只是在我的项目中做了类似的事情。使用FileWriter将简化部分工作。在这里你可以找到很好的教程。

BufferedWriter writer = null;
try
{
    writer = new BufferedWriter( new FileWriter( yourfilename));
    writer.write( yourstring);

}
catch ( IOException e)
{
}
finally
{
    try
    {
        if ( writer != null)
        writer.close( );
    }
    catch ( IOException e)
    {
    }
}

在Java 7中，您可以执行以下操作：

String content = "Hello File!";
String path = "C:/a.txt";
Files.write( Paths.get(path), content.getBytes());

这里有更多信息：http://www.drdobbs.com/jvm/java-se-7-new-file-io/231600403

基本上与这里的答案相同，但易于复制/粘贴，而且效果很好；-）

  import java.io.FileWriter;

  public void saveToFile(String data, String filename) {
    try (
      FileWriter fw = new FileWriter(filename)) {
      fw.write(data);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
  }

我倾向于尽可能依赖于库来进行这种操作。这使我不太可能意外地忽略一个重要的步骤（如上面狼鹬犯的错误）。上面建议了一些库，但我最喜欢的是GoogleGuava。Guava有一个名为Files的类，非常适合此任务：

// This is where the file goes.
File destination = new File("file.txt");
// This line isn't needed, but is really useful 
// if you're a beginner and don't know where your file is going to end up.
System.out.println(destination.getAbsolutePath());
try {
    Files.write(text, destination, Charset.forName("UTF-8"));
} catch (IOException e) {
    // Useful error handling here
}

如果希望将字符串中的回车字符保留在文件中下面是一个代码示例：

    jLabel1 = new JLabel("Enter SQL Statements or SQL Commands:");
    orderButton = new JButton("Execute");
    textArea = new JTextArea();
    ...


    // String captured from JTextArea()
    orderButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent ae) {
            // When Execute button is pressed
            String tempQuery = textArea.getText();
            tempQuery = tempQuery.replaceAll("\n", "\r\n");
            try (PrintStream out = new PrintStream(new FileOutputStream("C:/Temp/tempQuery.sql"))) {
                out.print(tempQuery);
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println(tempQuery);
        }

    });