java 字符串与文件相互转换

/**
* Prints some data to a file using a BufferedWriter
*/
private void writeToFile(File file, String txt) {


BufferedWriter bufferedWriter = null;


try {


// Construct the BufferedWriter object
bufferedWriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), "UTF-8"));


// Start writing to the output stream
bufferedWriter.write(txt);


} catch (FileNotFoundException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
} finally {
// Close the BufferedWriter
if (bufferedWriter != null) {
try {
bufferedWriter.flush();
bufferedWriter.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}


public String fileToText(HttpServletRequest request, String pathname) {


if (null == request) {
request = this.request;
}


String contextPath = request.getServletContext().getRealPath("");


File file = new File(contextPath + pathname);
if (!file.exists()) {
return "";
}
return fileToString(file);
}


/**
* Prints some data to a file using a BufferedWriter
*/
private String fileToString(File file) {


BufferedReader bufferedReader = null;


StringBuffer buffer = new StringBuffer();


try {


bufferedReader = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
while (bufferedReader.readLine() != null) {
buffer.append(bufferedReader.readLine());
}


} catch (FileNotFoundException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
return buffer.toString();
}