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在全国城市数据json格式的文本里筛选出几个指定的key
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部分json格式数据如下
{"sysCatPk": 459, "prntSysCatPk": null, "prntCd": "9100", "prntNmEn": "china", "prntNmCn": "中国", "cd": "9100.100", "nmEn": "beijingshi", "nmCn": "北京市", "methSysCatPk": 252, "methCd": "9100", "methNmEn": "china", "methNmCn": "中国", "desc": "", "viewSeq": "", "busSeq": "", "value": null, "level": 1, "childSysCatDtozList": [{ "sysCatPk": 460, "prntSysCatPk": 459, "prntCd": "9100.100", "prntNmEn": "beijingshi", "prntNmCn": "北京市", "cd": "9100.100.100", "nmEn": "beijingshi", "nmCn": "北京市", "methSysCatPk": 252, "methCd": "9100", "methNmEn": "china", "methNmCn": "中国", "desc": "", "viewSeq": "", "busSeq": "", "value": null, "level": 2, "childSysCatDtozList": [{ "sysCatPk": 461, "prntSysCatPk": 460, "prntCd": "9100.100.100", "prntNmEn": "beijingshi", "prntNmCn": "北京市", "cd": "9100.100.100.100", "nmEn": "dongchengqu", "nmCn": "东城区", "methSysCatPk": 252, "methCd": "9100", "methNmEn": "china", "methNmCn": "中国", "desc": "", "viewSeq": "", "busSeq": "", "value": null, "level": 3, "childSysCatDtozList": [], "top": false, "leaf": true }, { "sysCatPk": 462, "prntSysCatPk": 460, "prntCd": "9100.100.100", "prntNmEn": "beijingshi", "prntNmCn": "北京市", "cd": "9100.100.100.110", "nmEn": "xichengqu", "nmCn": "西城区", "methSysCatPk": 252, "methCd": "9100", "methNmEn": "china", "methNmCn": "中国", "desc": "", "viewSeq": "", "busSeq": "", "value": null, "level": 3, "childSysCatDtozList": [], "top": false, "leaf": true }, { "sysCatPk": 463, "prntSysCatPk": 460, "prntCd": "9100.100.100", "prntNmEn": "beijingshi", "prntNmCn": "北京市", "cd": "9100.100.100.120", "nmEn": "chongwenqu", "nmCn": "崇文区", "methSysCatPk": 252, "methCd": "9100", "methNmEn": "china", "methNmCn": "中国", "desc": "", "viewSeq": "", "busSeq": "", "value": null, "level": 3, "childSysCatDtozList": [], "top": false, "leaf": true }], "top": false, "leaf": false }], "top": true, "leaf": false } -
需要的json格式如下，只选取三个字段
[{"sysCatPk":"459","nmCn":"北京市","childSysCatDtozList": [{"sysCatPk":"460","nmCn":"北京市","childSysCatDtozList": [{"sysCatPk":"461","childSysCatDtozList":[],"nmCn":"东城区"}, {"sysCatPk":"462","childSysCatDtozList":[],"nmCn":"西城区"}, {"sysCatPk":"463","childSysCatDtozList":[],"nmCn":"崇文区"}, {"sysCatPk":"464","childSysCatDtozList":[],"nmCn":"宣武区"}, {"sysCatPk":"465","childSysCatDtozList":[],"nmCn":"朝阳区"}, {"sysCatPk":"466","childSysCatDtozList":[],"nmCn":"丰台区"}, {"sysCatPk":"467","childSysCatDtozList":[],"nmCn":"石景山区"}, {"sysCatPk":"468","childSysCatDtozList":[],"nmCn":"海淀区"}, {"sysCatPk":"469","childSysCatDtozList":[],"nmCn":"门头沟区"}, {"sysCatPk":"470","childSysCatDtozList":[],"nmCn":"房山区"}, {"sysCatPk":"471","childSysCatDtozList":[],"nmCn":"通州区"}, {"sysCatPk":"472","childSysCatDtozList":[],"nmCn":"顺义区"}, {"sysCatPk":"473","childSysCatDtozList":[],"nmCn":"昌平区"}, {"sysCatPk":"474","childSysCatDtozList":[],"nmCn":"大兴区"}, {"sysCatPk":"475","childSysCatDtozList":[],"nmCn":"平谷区"}, {"sysCatPk":"476","childSysCatDtozList":[],"nmCn":"怀柔区"}, {"sysCatPk":"477","childSysCatDtozList":[],"nmCn":"密云县"}, {"sysCatPk":"478","childSysCatDtozList":[],"nmCn":"延庆县"} }] }] -
实现方法：
- 创建一个实体类
@Data public class City { private String sysCatPk; private String nmCn; private List<City> childSysCatDtozList; }- 从文本中读取json数据
public class TextRead { public static String readFileContent(String fileName) { File file = new File(fileName); BufferedReader reader = null; StringBuffer sbf = new StringBuffer(); try { reader = new BufferedReader(new FileReader(file)); String tempStr; while ((tempStr = reader.readLine()) != null) { sbf.append(tempStr); } reader.close(); return sbf.toString(); } catch (IOException e) { e.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException e1) { e1.printStackTrace(); } } } return sbf.toString(); } }- 转换
public static void main(String[] asg) throws IOException { String str = TextRead.readFileContent("C:\Users\mengzhao\Desktop\全国城市数据json格式.txt"); JSONArray array = JSONArray.parseArray(str); List<City> cities = array.toJavaList(City.class); Object json = JSONArray.toJSON(cities); File file = new File("C:\Users\mengzhao\Desktop\全国城市数据json格式1.txt"); Writer out = new FileWriter(file); out.write(json.toString()); out.close(); }