Question

您好我面临操纵json结构的问题。我是gson的初学者。我从IoT平台获得了一个复杂的json结构，我可以获得结构的第一级（tenantid，timestamp）的值，但是当我想深入到结构时它会崩溃。我没有找到帮助元素进入gson文档来完成这个有效负载。我试图将一个类映射到它 - 它没有用，可能对我来说太复杂了...... 谢谢你的帮助！

/* The payload structure is as follow :  
 * {"payload": 
 *      "{
 *          \"tenantId\":\"56ab3a090cf2f00fce9ad9\",
 *          \"timestamp\":\"2017-07-15T10:56:27.124Z\",
 *          \"firingRule\":
 *          {
 *              \"id\":\"0b4e0dcd-4634-4f2-96ce-7ceefd95b584\",
 *              \"name\":\"testFR0StreamSample02-01\",
 *              \"enabled\":true,
 *              \"matchingRuleIds\": [\"e57927-be87-48dd-be42-8c01d13004d0\"],
 *              \"aggregationKeys\": [\"metadata.source\"],
 *              \"firingType\":\"ALWAYS\"
 *          },
 *          \"matchingContext\":
 *          {
 *              \"tenantId\":\"56ab3a090cf600fce9ad9\",
 *              \"timestamp\":\"2017-07-15T10:56:27.114Z\",
 *              \"matchingRule\":
 *              {
 *                  \"id\":\"e5ec7927-be7-48dd-be42-8c01d13004d0\",
 *                  \"name\":\"Test temperature > 20\",
 *                  \"enabled\":true,
 *                  \"dataPredicate\":
 *                  {
 *                      \">\":[{\"var\":\"value.temperature\"},20]}},
 *                      \"data\":
 *                      {
 *                          \"streamId\":\"android35739073120059\",
 *                          \"timestamp\":\"2017-07-15T10:56:27.106Z\",
 *                          \"location\":{\"lat\":48.872015,\"lon\":2.348264},
 *                          \"model\":\"ModelOABDemoApp00\",
 *                          \"value\":
 *                          {
 *                              \"revmin\":7505,
 *                              \"hygrometry\":98,
 *                              \"temperature\":92},
 *                              \"tags\":[\"OABDemoApp.00\"],
 *                              \"metadata\":
 *                              {
 *                                  \"source\":\"URN:LO:NSID:SENSOR:TESTFLGAPPOAB00000\",
 *                                  \"connector\":\"mqtt\"
 *                              }
 *                          }
 *                  }
 *          }"}
*/

//这是我的代码的摘录

   Gson gson = new Gson();
   String sLiveObjectsPayload  = "{\"tenantId\":\"56ab3a090cf2ff600fce9ad9\",\"timestamp\":\"2017-07-29T08:31:24.026Z\",\"firingRule\":{\"id\":\"0b4e0dcd-4634-4ef2-96ce-7ceefd95b584\",\"name\":\"testFR0StreamSample02-01\",\"enabled\":true,\"matchingRuleIds\":[\"e5ec7927-be87-48dd-be42-8c01d13004d0\"],\"aggregationKeys\":[\"metadata.source\"],\"firingType\":\"ALWAYS\"},\"matchingContext\":{\"tenantId\":\"56ab3a090cf2ff600fce9ad9\",\"timestamp\":\"2017-07-29T08:31:24.012Z\",\"matchingRule\":{\"id\":\"e5ec7927-be87-48dd-be42-8c01d13004d0\",\"name\":\"Test temperature > 20\",\"enabled\":true,\"dataPredicate\":{\">\":[{\"var\":\"value.temperature\"},20]}},\"data\":{\"streamId\":\"android357329073120059\",\"timestamp\":\"2017-07-29T08:31:23.992Z\",\"location\":{\"lat\":48.872015,\"lon\":2.348264},\"model\":\"ModelOABDemoApp00\",\"value\":{\"revmin\":9147,\"hygrometry\":70,\"temperature\":118},\"tags\":[\"OABDemoApp.00\"],\"metadata\":{\"source\":\"URN:LO:NSID:SENSOR:TESTFLGAPPOAB00000\",\"connector\":\"mqtt\"}}}}";
   JsonObject jsonPayload ;
   jsonPayload = gson.fromJson(sLiveObjectsPayload, JsonObject.class);

   String sTenantId ;
   String sTimeStamp ;
   String sFiringRule ;
   String sFiringRuleId ;
   String sName ;
   sTenantId = jsonPayload.get("tenantId").getAsString();           // ok
   sTimeStamp = jsonPayload.get("timestamp").getAsString();         // ok
   sFiringRuleId = jsonPayload.get("firingRule.id").getAsString();  // crash
   sFiringRule = jsonPayload.get("firingRule").getAsString();       // crash
   sName = jsonPayload.get("name").getAsString();                   // crash

Answer 1

您可以使用getAsJsonObject()访问子JSON对象。

sTenantId = jsonPayload.get("tenantId").getAsString();
sTimeStamp = jsonPayload.get("timestamp").getAsString();

JsonObject firingRule = jsonPayload.getAsJsonObject("firingRule");
sFiringRuleId = firingRule.get("id").getAsString();
sName = firingRule.get("name").getAsString();

使用gson进行json复杂的有效负载管理

1 个答案: