public class CursorFileManager implements CursorManager{
    public void write(String key, LongCursor cursor) throws IOException    {        File file = new File(key);        if (cursor == null) {            if (file.exists()) {                file.delete();            }            return;        }    FileWriter fileWriter = null;    try {        fileWriter = new FileWriter(file);        JSON.writeJSONStringTo(cursor, fileWriter, new SerializerFeature[0]);    } catch (Exception e) {        this.logger.error(e.getMessage(), e);    } finally {        if (fileWriter != null)            fileWriter.close();    }  }public LongCursor read(String key){    JSONReader reader = null;    try {        File file = new File(key);        this.logger.info("try to read cursor from file={}", file.getAbsolutePath());        if (!file.exists()) {            return null;        }        reader = new JSONReader(new FileReader(file));        LongCursor cursor = (LongCursor)reader.readObject(LongCursor.class);        return cursor;    } catch (Exception e) {        this.logger.error(e.getMessage(), e);    } finally {        if (reader != null)          reader.close();    }    return null;}

cursor格式：

{"biz":"false-0","extraInfo":1469203484000,"from":1469203208000,"to":1469203508000}

public LongCursor read() {    LongCursor cursor = cursorManager.read(cursorPath + "/" + fileName);    if (cursor != null) {        String biz = cursor.getBiz();        if (biz != null && biz.length() > 0) {            String[] secs = biz.split("-");            shouldWait = Boolean.parseBoolean(secs[0]);            if (secs.length > 1) {                completedOrderId = Long.valueOf(secs[1]);            }        }    }    return cursor;}public void write(LongCursor cursor) throws IOException {    cursor.setBiz(shouldWait + "-" + completedOrderId);    cursorManager.write(cursorPath + "/" + fileName, cursor);}