最近遇到了一个关于io的问题。一个4G的文件需要我读出来，然后处理下放到数据库里。4G，拿到的时候只是觉得大了点。怕啥，读出来，处理好，ok。保存。。。。。。
那么，开干吧。
@RequestMapping("xxxx")@ResponseBody @Transactional(readOnly = false,propagation = Propagation.REQUIRED)public String readText(HttpServletRequest request,String type){File file = new File("xxxx.json");StringBuilder result = new StringBuilder();try{BufferedReader br = new BufferedReader(new FileReader(file));//构造一个BufferedReader类来读取文件 String s = null; while((s = br.readLine())!=null){//使用readLine方法，一次读一行 JSONObject json = JSONObject.parseObject(s); //处理业务}br.close();}catch(Exception e){e.printStackTrace();}return result.toString(); }
明显，失败咧。根本读不出来。太大了，赶紧找外援。然后老大说要用流来处理（嘛是流），并且你要想办法把数据切割下。。。。。巨尴尬。好吧，滚滚爬爬，还是借鉴来了老大的代码。脸为何物？对于这个问题吗，不会就借鉴，借鉴了就要及时总结。
@RequestMapping("/xxxx")@ResponseBodypublic String uploadAreaPersonLocal(HttpServletRequest request, String fileName, String type) throws JSONErrorException {Map<String,Object> map = new HashMap<>(); Reader reader = null; int count = 0; try {StringBuilder builder = new StringBuilder();int charread = 0;JSONArray array = new JSONArray();reader = new InputStreamReader(new FileInputStream(fileName));// 读入多个字符到字符数组中，charread为一次读取字符数while ((charread = reader.read()) != -1) {if ((char)charread == '[') {break; }}while ((charread = reader.read()) != -1) {char tempChar = (char)charread; if (tempChar == ']') {break; }if (tempChar == '{') {builder.setLength(0); }builder.append(tempChar); if (tempChar == '}') {array.add(JSON.parseObject(builder.toString())); builder.setLength(0); }if (array.size() >= 10000) {array = new JSONArray(); count = count + 10000; }}if (array.size() > 0) {if (Integer.valueOf(type) == 1) {this.cityDataService.saveLivePeople(array); } else if(Integer.valueOf(type) == 2) {this.cityDataService.saveDailyPeople(array); }System.out.println("已保存：" + (count + array.size()));}} catch (Exception e1) {e1.printStackTrace(); } finally {if (reader != null) {try {reader.close(); } catch (IOException e1) {}}}map.put(Constant.CODE, "0"); map.put(Constant.MESSAGE, "success"); logger.info("城市自定义区域人口数据保存完成"); return JSON.toJSONString(map);}
BufferedReader
知识点： BufferReader 、Reader、File、FileInputStream
主要对IO的理解不够深刻。那么，需要认真的看一看io了。
