Java 按行读取文件

public String getFileContent(String fileName, int fromLine, int endLine) {
		File file = new File(fileName);
		// int total = Integer.parseInt(UnixCommand.WCCommand(file));
		int total = 10;
		if (endLine == 0) {
			return null;
		}
		if (fromLine == 0) {
			fromLine = 1;
		}
		if (fromLine > 0) {
			if (endLine > 0) {
				if (fromLine > endLine) {
					return null;
				}
			} else {
				endLine = total + endLine + 1;
			}
		} else {
			if (endLine > 0) {
				return null;
			} else {
				int temp = fromLine - endLine;
				fromLine = total + endLine + 1;
				endLine = fromLine + temp;
			}
		}

		StringBuilder content = new StringBuilder();
		LineNumberReader reader = null;
		FileReader in = null;
		try {
			in = new FileReader(file);
			reader = new LineNumberReader(in);
			while (true) {
				String s = reader.readLine();
				if (s == null)
					break;

				int i = reader.getLineNumber();
				if (i >= fromLine && i <= endLine) {
					content.append(s);
					content.append("\r");
				}
				if (i > endLine) {
					break;
				}
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if (reader != null)
					reader.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			try {
				if (in != null)
					in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return content.toString();
	}