java遍歷json字符串，取得相應KV值時，各種麻煩，比如將json中的list取出來轉為JSONArray，再將list中的object轉化為map，再取值（之前的做法），仙子啊通過阿里的fastjson，可以很方便的直接將str轉化為JSONArray，再將裡面的object強轉為JSONObject，然後再通過obj.getInteger(“key”)和obj.getString(“key”)等取值。
JSONArray json = (JSONArray) JSONArray.parse(str);for (Object obj : json) { JSONObject jo = (JSONObject)obj; int status = jo.getInteger("status"); String message= jo.getString("message"); System.out.println("status---" + status + "---message---" + message);}1.當json字符串中有數組和map對象，遍歷數據，數據格式如下：
[ { "status":0, "tags":[ "check:ntp" ], "timestamp":1492151922.198, "check":"datadog.agent.check_status", "host_name":"song-2", "message":null, "id":2 }, { "status":0, "tags":null, "timestamp":1492151922.2325, "check":"datadog.agent.up", "host_name":"song-2", "message":null, "id":5 }]解析上面json字符串數據，如果不使用如fastjson或者Gson時，解析方法如下：
方法一
/** * 主機詳情中，異常錯誤信息的報錯的平台服務狀態和message * @param str * @return * @throws Exception */ private List<Map<String,String>> operStr(String str) throws Exception{ List<Map<String,String>> mList = new ArrayList<Map<String,String>>();//探針開啟的服務名list JSONArray json = (JSONArray) JSONArray.parse(str); Map<String,Object> objMap = null; Map<String,String> resMap = null; for (Object obj : json) { objMap = Obj2Map(obj); @SuppressWarnings("unchecked") Map<String,Object> mObj = (Map<String, Object>) objMap.get("map"); int status = (Integer) mObj.get("status"); if(status != 0){ resMap = new HashMap<String,String>(); switch (status) { case 1: resMap.put("status","WARNING"); break; case 2: resMap.put("status","ERROR"); break; case 3: resMap.put("status","CRIT"); break; default: break; } resMap.put("serviceName", ((String) mObj.get("check")).split("//.")[0]); resMap.put("msg", (String)mObj.get("message")); mList.add(resMap); } } return mList; } /** * object轉map * @param obj * @return * @throws Exception */ public Map<String,Object> Obj2Map(Object obj) throws Exception{ if(obj == null){ return null; } Map<String,Object> map=new HashMap<String, Object>(); Field[] fields = obj.getClass().getDeclaredFields(); for(Field field:fields){ field.setAccessible(true); map.put(field.getName(), field.get(obj)); } return map; }方法二
/** * 主機詳情中，異常錯誤信息的報錯的平台服務狀態和message * @param str * @return * @throws Exception */ private List<Map<String,String>> operStr(String str) throws Exception{ List<Map<String,String>> mList = new ArrayList<Map<String,String>>();//探針開啟的服務名list JSONArray json = (JSONArray) JSONArray.parse(str); Map<String,String> resMap = null; for (Object obj : json) { JSONObject jo = (JSONObject)obj; int status = jo.getInteger("status"); if(status != 0){ resMap = new HashMap<String,String>(); switch (status) { case 1: resMap.put("status","WARNING"); break; case 2: resMap.put("status","ERROR"); break; case 3: resMap.put("status","CRIT"); break; default: break; } resMap.put("serviceName", (jo.getString("check")).split("//.")[0]); resMap.put("msg", jo.getString("message")); mList.add(resMap); } } return mList; }2.當json字符串中是數組包含數組時候，遍歷數據，數據格式如下：
[ [ "haproxy", "haproxy", 0, "ERROR", "swdfghyjuikl", { } ], [ "gearmand", "gearmand", 0, "ERROR", "'Found no valid connections in list: [<GearmanConnection localhost:4730 connected=False>]'", { "version":"[8, 4, 20]" } ]]方法一
/** * 通過查詢agentChecksStr解析得到異常信息* @param agentChecksStr * @return */ private List<Map<String,String>> getExceptInfoFromAgentChecks(String agentChecksStr){ List<Map<String,String>> mList = new ArrayList<Map<String,String>>();//探針開啟的服務名list //mList 主機詳情中，異常錯誤信息的報錯的平台服務狀態和message Object jsonArray = JSONArray.parse(agentChecksStr); @SuppressWarnings("unchecked") List<List<Object>> list= (List<List<Object>>) jsonArray; Map<String,String> map = null; for(int i=0;i<list.size();i++){ map = new HashMap<String,String>(); String status = list.get(i).get(3).toString(); if(!status.equals("OK")){ String serviceName = list.get(i).get(0).toString(); String msg = list.get(i).get(4).toString(); map.put("serviceName", serviceName); map.put("status", status); map.put("msg", msg); mList.add(map); } } return mList; }方法二
/** * 通過查詢agentChecksStr解析得到異常信息* @param agentChecksStr * @return */ private List<Map<String,String>> getExceptInfoFromAgentChecks(String agentChecksStr){ //探針開啟的服務名list List<Map<String,String>> mList = new ArrayList<Map<String,String>>(); JSONArray jsonArray = (JSONArray) JSONArray.parse(agentChecksStr); Map<String,String> map = null; for (Object obj : jsonArray) { map = new HashMap<String,String>(); JSONArray ja = (JSONArray)obj; String status = ja.getString(3); if(!status.equals("OK")){ String serviceName = ja.getString(0); String msg = ja.getString(4); map.put("serviceName", serviceName); map.put("status", status); map.put("msg", msg); mList.add(map); } } return mList; }Gson將json字符串轉化為json對象：
import com.google.gson.Gson;import com.google.gson.JsonArray;import com.google.gson.JsonElement;import com.google.gson.JsonObject;import com.google.gson.JsonParser;public class MainTest { public static void main(String[] args) throws Exception{ String jsonstr0 = "{/"alarmDetails/":{/"conditionDetails/":{/"alarmId/":7,/"alarmNodataNotifyTime/":1,/"alarmNowSeriesWaitTime/":2},/"conditionStatic/":{/"alarmId/":7,/"conditionAggregate/":/"avg/",/"conditionOperator/":1,/"conditionThresholdTime/":5,/"conditionThresholdValue/":/"123/"},/"metricDetails/":{/"alarmId/":7,/"metricAggregater/":/"avg/",/"metricBy/":/"host/",/"metricExcludeTag/":/"host:paas-177/",/"metricName/":/"system.cpu.user/",/"metricQ/":/"avg:system.cpu.user{#address:wuhan,!host:paas-177}by{host}/",/"metricTag/":/"#address:wuhan/"},/"notify/":[{/"alarmId/":7,/"notifyChannel/":5,/"notifyUserId/":1},{/"alarmId/":7,/"notifyChannel/":5,/"notifyUserId/":2}],/"view/":{/"alarmExpression/":/"avg(last_5m)avg:system.cpu.user{#address:wuhan,!host:paas-177}by{host}>123.0/",/"alarmId/":7,/"alarmLastValue/":/"UP/",/"alarmName/":/"static_metric/",/"alarmStatus/":1,/"alarmType/":2,/"alarmTypeJoin/":3,/"createTime/":/"2017-06-28 17:25:52.0/",/"createUserId/":1,/"isDisable/":false,/"lastAlarmTime/":/"2017-06-28 17:25:27.0/",/"metricName/":/"system.cpu.user/",/"metricTag/":/"#address:wuhan/",/"updateTime/":/"2017-06-29 15:49:18.0/"}},/"alarmId/":7,/"allMark/":{/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/":{/"changePutTime/":true,/"lastPutTsdbTime/":1499655343,/"lastSuccessCheckTime/":1499655349,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"tagMap/":{/"host/":/"cfeng-4/",/"#address/":/"wuhan/",/"!host/":/"paas-177/"}}},/"joinType/":3,/"useMetricUnit/":/"percent/",/"validataDetails/":{/"status/":0,/"validataMerges/":[{/"alarmMarkDto/":{/"changePutTime/":true,/"lastPutTsdbTime/":1499655343,/"lastSuccessCheckTime/":1499655349,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"tagMap/":{/"host/":/"cfeng-4/",/"#address/":/"wuhan/",/"!host/":/"paas-177/"}},/"status/":0,/"tag/":/"host:cfeng-4/",/"validataNodata/":{/"currentTime/":1499655349,/"isNodata/":false,/"lastSuccessCheckTime/":1499655349,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"tag/":{/"host/":/"cfeng-4/",/"#address/":/"wuhan/",/"!host/":/"paas-177/"},/"thresholdTime/":60},/"validataStatic/":{/"converToThresholdValue/":123.0,/"end/":1499655343,/"intervalAggregator/":/"avg/",/"isAlart/":true,/"operator/":1,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"start/":1499655043,/"sysUnit/":/"percent/",/"tag/":{/"#address/":/"wuhan/",/"host/":/"cfeng-4/",/"!host/":/"paas-177/"},/"thresholdTime/":300,/"thresholdValue/":/"123/",/"value/":5.715769243240357}}],/"validataTimeSeconds/":1499655349}}"; String jsonstr1 = "{/"alarmDetails/":{/"conditionDetails/":{/"alarmId/":7,/"alarmNodataNotifyTime/":1,/"alarmNowSeriesWaitTime/":2},/"conditionStatic/":{/"alarmId/":7,/"conditionAggregate/":/"avg/",/"conditionOperator/":1,/"conditionThresholdTime/":5,/"conditionThresholdValue/":/"123/"},/"metricDetails/":{/"alarmId/":7,/"metricAggregater/":/"avg/",/"metricBy/":/"host/",/"metricExcludeTag/":/"host:paas-177/",/"metricName/":/"system.cpu.user/",/"metricQ/":/"avg:system.cpu.user{#address:wuhan,!host:paas-177}by{host}/",/"metricTag/":/"#address:wuhan/"},/"notify/":[{/"alarmId/":7,/"notifyChannel/":5,/"notifyUserId/":1},{/"alarmId/":7,/"notifyChannel/":5,/"notifyUserId/":2}],/"view/":{/"alarmExpression/":/"avg(last_5m)avg:system.cpu.user{#address:wuhan,!host:paas-177}by{host}>123.0/",/"alarmId/":7,/"alarmLastValue/":/"UP/",/"alarmName/":/"static_metric/",/"alarmStatus/":1,/"alarmType/":2,/"alarmTypeJoin/":3,/"createTime/":/"2017-06-28 17:25:52.0/",/"createUserId/":1,/"isDisable/":false,/"lastAlarmTime/":/"2017-06-28 17:25:27.0/",/"metricName/":/"system.cpu.user/",/"metricTag/":/"#address:wuhan/",/"updateTime/":/"2017-06-29 15:49:18.0/"}},/"alarmId/":7,/"allMark/":{/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/":{/"changePutTime/":true,/"lastPutTsdbTime/":1499655374,/"lastSuccessCheckTime/":1499655379,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"tagMap/":{/"host/":/"cfeng-4/",/"#address/":/"wuhan/",/"!host/":/"paas-177/"}}},/"joinType/":3,/"useMetricUnit/":/"percent/",/"validataDetails/":{/"status/":0,/"validataMerges/":[{/"alarmMarkDto/":{/"changePutTime/":true,/"lastPutTsdbTime/":1499655374,/"lastSuccessCheckTime/":1499655379,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"tagMap/":{/"host/":/"cfeng-4/",/"#address/":/"wuhan/",/"!host/":/"paas-177/"}},/"status/":0,/"tag/":/"host:cfeng-4/",/"validataNodata/":{/"currentTime/":1499655379,/"isNodata/":false,/"lastSuccessCheckTime/":1499655379,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"tag/":{/"host/":/"cfeng-4/",/"#address/":/"wuhan/",/"!host/":/"paas-177/"},/"thresholdTime/":60},/"validataStatic/":{/"converToThresholdValue/":123.0,/"end/":1499655374,/"intervalAggregator/":/"avg/",/"isAlart/":true,/"operator/":1,/"series/":/"avg:system.cpu.user{host:cfeng-4,#address:wuhan,!host:paas-177}/",/"start/":1499655074,/"sysUnit/":/"percent/",/"tag/":{/"#address/":/"wuhan/",/"host/":/"cfeng-4/",/"!host/":/"paas-177/"},/"thresholdTime/":300,/"thresholdValue/":/"123/",/"value/":5.089640821729388}}],/"validataTimeSeconds/":1499655379}}"; Set<String> set = new HashSet<String>(); set.add(jsonstr0); set.add(jsonstr1); Gson gs = new Gson(); List<Object> eventList = new ArrayList<Object>(); for (String str : set) { JsonObject returnData = new JsonParser().parse(str).getAsJsonObject(); JsonObject ad = returnData.get("alarmDetails").getAsJsonObject(); JsonObject vd = returnData.get("validataDetails").getAsJsonObject(); JsonArray vm = vd.get("validataMerges").getAsJsonArray(); JsonArray nf = ad.get("notify").getAsJsonArray(); JsonObject v = ad.get("view").getAsJsonObject(); String validataTimeSeconds = vd.get("validataTimeSeconds").toString(); for (JsonElement je : vm) { je.getAsJsonObject().add("view", v); je.getAsJsonObject().add("notify", nf); je.getAsJsonObject().addProperty("validataTimeSeconds", Long.parseLong(validataTimeSeconds)); eventList.add(je); } } for (Object obj : eventList) { String inParam = gs.toJson(obj); System.out.println(inParam); } System.out.println(gs.toJson(eventList)); }} //獲取設備信息（只有硬件設備和虛擬設備有）HashMap<String,String> paramMap = new HashMap<String,String>();paramMap.put("hostid", mHostId);paramMap.put("ptype", dto.getPtype());paramMap.put("type_flag", dto.getTypeFlag());paramMap.put("api_key", apikey);String resStr = HttpUtils.get(DEVICE_INFO_URL, paramMap);JSONObject jobj = JSON.parseObject(resStr);JSONObject obj = (JSONObject)jobj.get("result");if(obj.size() != 0){ String restr = jobj.get("result").toString(); DeviceInfoDto deviceInfoDto = new Gson().fromJson(restr, DeviceInfoDto.class); dto.setDeviceInfo(deviceInfoDto);} List<Map<Integer, Long>> result = new ArrayList<Map<Integer, Long>>();Map<String, String> timeMap = null;List<Map<String, String>> timeArr = new ArrayList<Map<String, String>>();for (int j = 0; j < result.size(); j++) {timeMap = new HashMap<String, String>();if (j == result.size() - 1) { timeMap.put("startTime",result.get(j).get(result.get(j).keySet().iterator().next()) + ""); timeMap.put("endTime", System.currentTimeMillis() + "");} else { timeMap.put("startTime", result.get(j).get(result.get(j).keySet().iterator().next()) + ""); timeMap.put("endTime", (result.get(j+1).get(result.get(j+1).keySet().iterator().next()) - 1) + "");}timeMap.put("hostName", "*");//1:info,2:error,3:success,4:warningInteger key = result.get(j).keySet().iterator().next();if (key == 1) { timeMap.put("status", "info");} else if (key == 2) { timeMap.put("status", "error");} else if (key == 3) { timeMap.put("status", "success");} else if (key == 4) { timeMap.put("status", "warning");} timeArr.add(timeMap);}以上這篇Java遍歷json字符串取值的實例就是小編分享給大家的全部內容了，希望能給大家一個參考，也希望大家多多支持武林網。