Java文件读写 & 输出换行符

public static String[] readFile(String readFilePath) throws Exception {
FileReader reader = new FileReader(readFilePath);
BufferedReader br = new BufferedReader(reader);
String readContent[] = new String[999999];
int i = 0;
while((readContent[i] = br.readLine()) != null) {
i++;
}
br.close();
reader.close();
return readContent;
}

public static void writeFile(String writeFilePath,String writeContent[]) throws Exception {
File file = new File(writeFilePath);
FileWriter filewriter = new FileWriter(file, true);
String lineSeparator = (String) java.security.AccessController.doPrivileged(new sun.security.action.GetPropertyAction("line.separator"));
for (int i=0;i<writeContent.length;i++) {
if (writeContent[i] != null) {
filewriter.write(writeContent[i]+lineSeparator);
}
}
filewriter.close();
}