json解析

380万条的json格式的数据进行解析

数据格式如下：

{
  "_id" : "b454e650cb1a4fa4a2f2bd6899fbfa73",
  "bb" : "116.2451019,39.8486099,116.2451019,39.8486099",
  "pts" : [{
      "1" : 0,
      "2" : 39.8486099,
      "3" : 116.2451019,
      "4" : 0.0,
      "5" : 0.0,
      "6" : "2012-03-07 14:25:08",
      "7" : "2012-03-07 14:25:10",
      "8" : "2",
      "9" : 0.0,
      "10" : 1
    }, {
      "1" : 1,
      "2" : 39.8486099,
      "3" : 116.2451019,
      "4" : 0.0,
      "5" : 0.0,
      "6" : "2012-03-07 14:25:16",
      "7" : "2012-03-07 14:25:17",
      "8" : "1",
      "9" : 0.0,
      "10" : 1
    }, {
      "1" : 2,
      "2" : 39.8486099,
      "3" : 116.2451019,
      "4" : -1.0,
      "5" : 0.0,
      "6" : "2012-03-07 14:25:18",
      "7" : "2012-03-07 14:25:20",
      "8" : "1",
      "9" : 0.0,
      "10" : 1
    }]
}

获取“_id”值和“bb”属性值（两点的经纬度坐标），获取“pts”属性中第一个标签6的值（起始时间）和最后一个标签7的属性值（终止时间），并根据经纬度计算两点之间的距离，根据起始时间和终止时间计算其时间差，得到每个“_id”的对应的距离和时间差

private final double PI = 3.1415926; //圆周率private final static double earthRadius = 6371; //地球半径，单位为KMpublic static void parseJson(BufferedReader bufferedReader) throws IOException, ParseException, java.text.ParseException{String line = ""; //一行一行的形式读取文件String[] pts6FirstTime =null;//第一个坐标点标签6的时间String pts6Time ="";String ptsTime7 = "";String reslut = ""; //计算最终结果double betweenTime = 0.0d;//轨迹点之间的时间差，以小时（h）为单位//longitude1、longitude2、dimension1、dimension2分别为经度坐标和维度坐标double longitude1 = 0.0d;double dimension1 = 0.0d;double longitude2 = 0.0d;double dimension2 = 0.0d; //设置时间格式DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//创建json解析对象JSONParser jsonParser = new JSONParser();//创建一个distanceAndTime对象DistanceAndTime distanceAndTime = new DistanceAndTime();while((line = bufferedReader.readLine())!=null){//开始解析JSONObject jsonObject = (JSONObject)jsonParser.parse(line);String _id = (String) jsonObject.get("_id");//得到轨迹的id号String bb = (String) jsonObject.get("bb");//得到轨迹的经纬度坐标bb//经纬度坐标是以","进行分割的String[] longitudeDismension = bb.split(",");//Double.valueOf()把string类型转换为double类型longitude1 = Double.valueOf(longitudeDismension[0]);dimension1 = Double.valueOf(longitudeDismension[1]);longitude2 = Double.valueOf(longitudeDismension[2]);dimension2 = Double.valueOf(longitudeDismension[3]);//计算具有经纬度的两坐标间的距离double bbDistance = distanceAndTime.getDistance(longitude1, dimension1, longitude2, dimension2);//解析pts中的内容JSONArray ptsjsonArray = (JSONArray)jsonObject.get("pts");Iterator iterator = ptsjsonArray.iterator();//解析pts中标签6的内容，并得到第一个标签6的内容while(iterator.hasNext()){JSONObject pts6JSONObject = (JSONObject)iterator.next();pts6Time = pts6JSONObject.get("6").toString();pts6FirstTime = pts6Time.split("\r\n");break;//对于标签6的时间，只要第一个时间}//解析pts中标签7的内容，并得到最后一个标签7的内容while(iterator.hasNext()){JSONObject pts7jsonobject = (JSONObject)iterator.next();ptsTime7 = pts7jsonobject.get("7").toString();}//计算轨迹的时间差，单位为小时（H）Date date1 = dateFormat.parse(ptsTime7);Date date2 = dateFormat.parse(pts6FirstTime[0]);betweenTime = (date1.getTime()-date2.getTime())/1000.0/3600.0;reslut = _id+"\t"+bbDistance+"\t"+betweenTime;writeToLocal(reslut);//System.out.println(reslut);}}//已知经纬度的轨迹点，计算两个轨迹点之间的距离，单位为KMpublic double getDistance(double longitude1,double dimension1,double longitude2,double dimension2){double x,y,distance;x = (longitude1 - longitude2)*PI*earthRadius*Math.cos(((dimension1+dimension2)/2)*PI/180)/180;y = (dimension1-dimension2)*PI*earthRadius/180;distance = Math.hypot(x, y);return distance;}//计算结果输出public static void writeToLocal(String string) throws IOException{File outFile = new File("D://0820--Study//轨迹点数据//result.json");if (!outFile.exists()) {outFile.createNewFile();}//FileOutputStream设置为true，是为了后一条结果记录覆盖前一条结果记录FileOutputStream fileOutputStream = new FileOutputStream(outFile,true);OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream);BufferedWriter bufferedWriter = new BufferedWriter(outputStreamWriter);bufferedWriter.write(string);bufferedWriter.newLine();bufferedWriter.flush();bufferedWriter.close();outputStreamWriter.close();fileOutputStream.close();}