本文有个不错的示例，主要讲解如何将内容写到txt文档里面、读取文件里面的内容以及清除txt文件里面的内容
1、将内容写到txt文档里面
               代码如下:

public static void writeFile() {
String txtFileName = "emailRecord.txt";
String directoryPath = "";
try {
directoryPath = WebplusContext.getRealPath("/apps/schoolfellow/upload/smsRecord");
File directory = new File(directoryPath);
if (!directory.exists()) {
directory.mkdirs();
}
File txtFile = new File(directoryPath, txtFileName);
FileOutputStream out = new FileOutputStream(txtFile, true);
String line = System.getProperty("line.separator");
String smsContent = "将内容写到txt文件里面！" + line;
out.write(smsContent.toString().getBytes("GBK"));
out.close();
} catch (Exception ex) {
log.error("将结果写入文件失败！", ex);
}
}

2、读取文件里面的内容
               代码如下:

public void readerFile() {
String filePath = WebplusContext.getServletContext().getRealPath("/apps/schoolfellow/upload/emailRecord/emailRecord.txt");
FileInputStream fis = null;
try {
fis = new FileInputStream(filePath);
InputStreamReader reader = new InputStreamReader(fis, "GBK");
BufferedReader br = new BufferedReader(reader);
String info = "";
schoolfellows = new ArrayList<SchoolfellowDataViewWrap>();
while ((info = br.readLine()) != null) {
System.out.println(info);
}
br.close();
fis.close();
} catch (Exception ex) {
log.error("读取数据失败", ex);
} finally {
}
}

3、清除txt文件里面的内容
               代码如下:

public void clearFileContent() {
String filePath = WebplusContext.getServletContext().getRealPath("/apps/schoolfellow/upload/emailRecord/emailRecord.txt");
try {
FileOutputStream out = new FileOutputStream(filePath,false);
out.write(new String("").getBytes());
out.close();
script = "alert('清空发送邮件日志成功！');";
} catch (Exception ex) {
script = "alert('清空文件的内容失败,因为没有发送邮件日志文件！');";
}
}

非常好教学

不错，阅读了，受益匪浅