java 把json数据转成数组进行操作_咸鱼爸爸_java json字符串转数组

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这里有一个数组，我们要做的先把它转成数组，然后是看他的数据里有没有“date”为12-17的日期，如果没有则新增一条。

[\n" + "\n" + "{\n" + "\"date\":\"12-22\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + " {\n" + "\"date\":\"12-17\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + " {\n" + "\"date\":\"12-19\",\n" + " \"A\": 1999,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + "{\n" + "\"date\":\"12-16\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + "{\n" + "\"date\":\"12-19\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " }\n" + "]

首先我们先去pom里把这个加进去

<dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.4</version> </dependency>

输入json（记得要加双引号）

public static void main(String[] args) { String a = "[\n" + "\n" + "{\n" + "\"date\":\"12-22\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + " {\n" + "\"date\":\"12-17\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + " {\n" + "\"date\":\"12-19\",\n" + " \"A\": 1999,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + "{\n" + "\"date\":\"12-16\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " },\n" + "{\n" + "\"date\":\"12-19\",\n" + " \"A\": 10,\n" + " \"B\": 13.8,\n" + " \"C\": 16.8\n" + " }\n" + "]";

然后把json转成数组

JSONArray array=JSON.parseArray(a);

按“date”大小进行排序（前面需要搞一个实体类Getter和Setter还有toString）

List<StreamTese> list = JSONObject.parseArray(array.toJSONString(),StreamTese.class); List streamTese= list.stream().sorted(Comparator.comparing(StreamTese::getDate).reversed()).collect(toList()); System.out.println(streamTese);

获取当前时间（下面要做的只是同月不同日的比较，时间格式只取“MM-dd”就可以了）

//获取系统当前时间 Date date = new Date(); //时间格式 SimpleDateFormat simpleDateFormat = new SimpleDateFormat("MM-dd"); String now=simpleDateFormat.format(date);

继续循环判断

boolean b=false; int i=0; for ( i = 0; i <array.size() ; i++) { //判断array数组中有没有和系统当前日期一样的数据“date” //如果数组中没有等于系统当前时间的date，b为true。 if(!array.getJSONObject(i).getString("date").equals(now)) { b=!b; } } //如果b为false则新增 if (b){ Map<String,Object> map=new HashMap<>(); map.put("date","12-16"); map.put("A","10"); map.put("B","12.3"); map.put("C","10.6"); array.add(map); System.out.println(streamTese); }else { //JSONObject jsonObject=array.getJSONObject(i-1); //System.out.println(jsonObject.getString("date")); //System.out.println(jsonObject.getString("A")); //System.out.println(jsonObject.getString("B")); //System.out.println(jsonObject.getString("C")); System.out.println(streamTese); } } } 打印结果： [{"date":"12-22","A":10,"B":13.8,"C":16.8},{"date":"12-17","A":10,"B":13.8,"C":16.8},{"date":"12-16","A":1999,"B":13.8,"C":16.8},{"date":"12-19","A":10,"B":13.8,"C":16.8},{"date":"12-19","A":10,"B":13.8,"C":16.8}] [{"date":"12-22","A":10,"B":13.8,"C":16.8},{"date":"12-19","A":10,"B":13.8,"C":16.8},{"date":"12-19","A":1999,"B":13.8,"C":16.8},{"date":"12-17","A":10,"B":13.8,"C":16.8},{"date":"12-16","A":10,"B":13.8,"C":16.8}]

如果数组中没有“date”为12-16的数据，则新增

打印结果： [{"date":"12-22","A":10,"B":13.8,"C":16.8},{"date":"12-17","A":10,"B":13.8,"C":16.8},{"date":"12-16","A":1999,"B":13.8,"C":16.8},{"date":"12-19","A":10,"B":13.8,"C":16.8},{"date":"12-19","A":10,"B":13.8,"C":16.8}] [{"date":"12-22","A":10,"B":13.8,"C":16.8},{"date":"12-19","A":10,"B":13.8,"C":16.8},{"date":"12-19","A":1999,"B":13.8,"C":16.8},{"date":"12-17","A":10,"B":13.8,"C":16.8},{"date":"12-17","A":10,"B":13.8,"C":16.8},{"date":"12-16","A":"10","B":"12.3","C":"10.6"}]