我遇到了一个问题，我的逻辑无法从 Twitter 提要中检索 JSON 数组中的前两个坐标。我正在使用Jackson JsonNode来检索Twitter提要。
以下是我首先验证节点是否为空的逻辑，如果它不为空，那么我尝试从平面上检索前两个 lon/lat 坐标。
问题是它永远无法检索转推的坐标 -> 地点 -> Bounding_box -> 坐标 -> 得到 0 0 和得到 0 1
源代码逻辑
if(root.path("retweeted_status").path("place").path("bounding_box").get("coordinates") != null){
lon = root.path("retweeted_status").path("place").path("bounding_box").path("coordinates").get(0).get(0).textValue();
lat = root.path("retweeted_status").path("place").path("bounding_box").path("coordinates").get(0).get(1).textValue();
if(root.path("retweeted_status").path("place").get("full_name") != null) {
userlocation = root.path("retweeted_status").path("place").get("full_name").textValue();
}
}
我正在尝试检索的部分，bounding_box数组中的前两个地理代码
"place": {
"id": "5a110d312052166f",
"url": "https://api.twitter.com/1.1/geo/id/5a110d312052166f.json",
"place_type": "city",
"name": "San Francisco",
"full_name": "San Francisco, CA",
"country_code": "US",
"country": "United States",
"bounding_box": {
"type": "Polygon",
"coordinates": [
[
[-122.514926, 37.708075],
[-122.514926, 37.833238],
[-122.357031, 37.833238],
[-122.357031, 37.708075]
]
]
},
"attributes": {}
},
示例 JSON
{
"created_at":"Fri Feb 05 01:36:27 +0000 2016",
"id":695420692209111000,
"id_str":"695420692209111040",
"text":"RT @Sayhop: When your boyfriend doesn't watch your show #RealFansGetIt X1 @XFINITY #ad https://t.co/E4H3zO92nV",
"source":"<a href="http://twitter.com/download/iphone" rel="nofollow">Twitter for iPhone</a>",
"truncated":false,
"in_reply_to_status_id":null,
"in_reply_to_status_id_str":null,
"in_reply_to_user_id":null,
"in_reply_to_user_id_str":null,
"in_reply_to_screen_name":null,
"user":{
"id":278162142,
"id_str":"278162142",
"name":"Alexeia ♡",
"screen_name":"_vievelv_",
"location":null,
"url":null,
"description":"Itty Bitty ❤️",
"protected":false,
"verified":false,
"followers_count":1571,
"friends_count":1246,
"listed_count":0,
"favourites_count":344,
"statuses_count":21194,
"created_at":"Wed Apr 06 18:46:36 +0000 2011",
"utc_offset":-18000,
"time_zone":"Eastern Time (US & Canada)",
"geo_enabled":true,
"lang":"en",
"contributors_enabled":false,
"is_translator":false,
"profile_background_color":"642D8B",
"profile_background_image_url":"http://pbs.twimg.com/profile_background_images/656263432/w1zrzuisccmzjk0qhv5h.jpeg",
"profile_background_image_url_https":"https://pbs.twimg.com/profile_background_images/656263432/w1zrzuisccmzjk0qhv5h.jpeg",
"profile_background_tile":true,
"profile_link_color":"FF00EE",
"profile_sidebar_border_color":"65B0DA",
"profile_sidebar_fill_color":"7AC3EE",
"profile_text_color":"3D1957",
"profile_use_background_image":true,
"profile_image_url":"http://pbs.twimg.com/profile_images/652259214774128640/O8LDMd8c_normal.jpg",
"profile_image_url_https":"https://pbs.twimg.com/profile_images/652259214774128640/O8LDMd8c_normal.jpg",
"profile_banner_url":"https://pbs.twimg.com/profile_banners/278162142/1441077378",
"default_profile":false,
"default_profile_image":false,
"following":null,
"follow_request_sent":null,
"notifications":null
},
"geo":null,
"coordinates":null,
"place":null,
"contributors":null,
"retweeted_status":{
"created_at":"Fri Jan 22 20:19:36 +0000 2016",
"id":690629910960799700,
"id_str":"690629910960799744",
"text":"When your boyfriend doesn't watch your show #RealFansGetIt X1 @XFINITY #ad https://t.co/E4H3zO92nV",
"source":"<a href="http://twitter.com/download/iphone" rel="nofollow">Twitter for iPhone</a>",
"truncated":false,
"in_reply_to_status_id":null,
"in_reply_to_status_id_str":null,
"in_reply_to_user_id":null,
"in_reply_to_user_id_str":null,
"in_reply_to_screen_name":null,
"user":{
"id":25011208,
"id_str":"25011208",
"name":"Sara Hopkins",
"screen_name":"Sayhop",
"location":"Atlanta, GA",
"url":"http://shortyawards.com/8th/sayhop",
"description":"never bored || TV host/social media creator ⭐️⭐️⭐️⭐️⭐️ IG/snapchat: sayhop",
"protected":false,
"verified":true,
"followers_count":50761,
"friends_count":998,
"listed_count":98,
"favourites_count":13178,
"statuses_count":4231,
"created_at":"Wed Mar 18 02:31:51 +0000 2009",
"utc_offset":-18000,
"time_zone":"Eastern Time (US & Canada)",
"geo_enabled":true,
"lang":"en",
"contributors_enabled":false,
"is_translator":false,
"profile_background_color":"000000",
"profile_background_image_url":"http://pbs.twimg.com/profile_background_images/260784476/Twitter1.jpg",
"profile_background_image_url_https":"https://pbs.twimg.com/profile_background_images/260784476/Twitter1.jpg",
"profile_background_tile":false,
"profile_link_color":"51D4C2",
"profile_sidebar_border_color":"DBCFAD",
"profile_sidebar_fill_color":"0F0E0B",
"profile_text_color":"AD4C9E",
"profile_use_background_image":true,
"profile_image_url":"http://pbs.twimg.com/profile_images/688163946512007168/CRqMjOgp_normal.jpg",
"profile_image_url_https":"https://pbs.twimg.com/profile_images/688163946512007168/CRqMjOgp_normal.jpg",
"profile_banner_url":"https://pbs.twimg.com/profile_banners/25011208/1414548876",
"default_profile":false,
"default_profile_image":false,
"following":null,
"follow_request_sent":null,
"notifications":null
},
"geo":null,
"coordinates":null,
"place":{
"id":"5a110d312052166f",
"url":"https://api.twitter.com/1.1/geo/id/5a110d312052166f.json",
"place_type":"city",
"name":"San Francisco",
"full_name":"San Francisco, CA",
"country_code":"US",
"country":"United States",
"bounding_box":{
"type":"Polygon",
"coordinates":[
[
[
-122.514926,
37.708075
],
[
-122.514926,
37.833238
],
[
-122.357031,
37.833238
],
[
-122.357031,
37.708075
]
]
]
},
"attributes":{
}
},
"contributors":null,
"is_quote_status":false,
"retweet_count":4276,
"favorite_count":14129,
"entities":{
"hashtags":[
{
"text":"RealFansGetIt",
"indices":[
45,
59
]
},
{
"text":"ad",
"indices":[
72,
75
]
}
],
"urls":[
],
"user_mentions":[
{
"screen_name":"XFINITY",
"name":"XFINITY",
"id":14996251,
"id_str":"14996251",
"indices":[
63,
71
]
}
],
"symbols":[
],
"media":[
{
"id":690629837333999600,
"id_str":"690629837333999617",
"indices":[
76,
99
],
"media_url":"http://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"media_url_https":"https://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"url":"https://t.co/E4H3zO92nV",
"display_url":"pic.twitter.com/E4H3zO92nV",
"expanded_url":"http://twitter.com/Sayhop/status/690629910960799744/video/1",
"type":"photo",
"sizes":{
"thumb":{
"w":150,
"h":150,
"resize":"crop"
},
"medium":{
"w":600,
"h":338,
"resize":"fit"
},
"small":{
"w":340,
"h":191,
"resize":"fit"
},
"large":{
"w":1024,
"h":576,
"resize":"fit"
}
}
}
]
},
"extended_entities":{
"media":[
{
"id":690629837333999600,
"id_str":"690629837333999617",
"indices":[
76,
99
],
"media_url":"http://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"media_url_https":"https://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"url":"https://t.co/E4H3zO92nV",
"display_url":"pic.twitter.com/E4H3zO92nV",
"expanded_url":"http://twitter.com/Sayhop/status/690629910960799744/video/1",
"type":"video",
"sizes":{
"thumb":{
"w":150,
"h":150,
"resize":"crop"
},
"medium":{
"w":600,
"h":338,
"resize":"fit"
},
"small":{
"w":340,
"h":191,
"resize":"fit"
},
"large":{
"w":1024,
"h":576,
"resize":"fit"
}
},
"video_info":{
"aspect_ratio":[
16,
9
],
"duration_millis":11233,
"variants":[
{
"bitrate":2176000,
"content_type":"video/mp4",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/1280x720/OY7P8akLAqM_C2J1.mp4"
},
{
"bitrate":320000,
"content_type":"video/mp4",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/320x180/HlqkHHrC7SK6cgR8.mp4"
},
{
"bitrate":832000,
"content_type":"video/webm",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/640x360/FfLYyLagrUn8VGgy.webm"
},
{
"bitrate":832000,
"content_type":"video/mp4",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/640x360/FfLYyLagrUn8VGgy.mp4"
},
{
"content_type":"application/x-mpegURL",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/pl/cXSu_jFCOj5Wcte5.m3u8"
},
{
"content_type":"application/dash+xml",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/pl/cXSu_jFCOj5Wcte5.mpd"
}
]
}
}
]
},
"favorited":false,
"retweeted":false,
"possibly_sensitive":false,
"filter_level":"low",
"lang":"en"
},
"is_quote_status":false,
"retweet_count":0,
"favorite_count":0,
"entities":{
"hashtags":[
{
"text":"RealFansGetIt",
"indices":[
57,
71
]
},
{
"text":"ad",
"indices":[
84,
87
]
}
],
"urls":[
],
"user_mentions":[
{
"screen_name":"Sayhop",
"name":"Sara Hopkins",
"id":25011208,
"id_str":"25011208",
"indices":[
3,
10
]
},
{
"screen_name":"XFINITY",
"name":"XFINITY",
"id":14996251,
"id_str":"14996251",
"indices":[
75,
83
]
}
],
"symbols":[
],
"media":[
{
"id":690629837333999600,
"id_str":"690629837333999617",
"indices":[
88,
111
],
"media_url":"http://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"media_url_https":"https://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"url":"https://t.co/E4H3zO92nV",
"display_url":"pic.twitter.com/E4H3zO92nV",
"expanded_url":"http://twitter.com/Sayhop/status/690629910960799744/video/1",
"type":"photo",
"sizes":{
"thumb":{
"w":150,
"h":150,
"resize":"crop"
},
"medium":{
"w":600,
"h":338,
"resize":"fit"
},
"small":{
"w":340,
"h":191,
"resize":"fit"
},
"large":{
"w":1024,
"h":576,
"resize":"fit"
}
},
"source_status_id":690629910960799700,
"source_status_id_str":"690629910960799744",
"source_user_id":25011208,
"source_user_id_str":"25011208"
}
]
},
"extended_entities":{
"media":[
{
"id":690629837333999600,
"id_str":"690629837333999617",
"indices":[
88,
111
],
"media_url":"http://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"media_url_https":"https://pbs.twimg.com/ext_tw_video_thumb/690629837333999617/pu/img/ofj5PsOGsynefono.jpg",
"url":"https://t.co/E4H3zO92nV",
"display_url":"pic.twitter.com/E4H3zO92nV",
"expanded_url":"http://twitter.com/Sayhop/status/690629910960799744/video/1",
"type":"video",
"sizes":{
"thumb":{
"w":150,
"h":150,
"resize":"crop"
},
"medium":{
"w":600,
"h":338,
"resize":"fit"
},
"small":{
"w":340,
"h":191,
"resize":"fit"
},
"large":{
"w":1024,
"h":576,
"resize":"fit"
}
},
"source_status_id":690629910960799700,
"source_status_id_str":"690629910960799744",
"source_user_id":25011208,
"source_user_id_str":"25011208",
"video_info":{
"aspect_ratio":[
16,
9
],
"duration_millis":11233,
"variants":[
{
"bitrate":2176000,
"content_type":"video/mp4",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/1280x720/OY7P8akLAqM_C2J1.mp4"
},
{
"bitrate":320000,
"content_type":"video/mp4",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/320x180/HlqkHHrC7SK6cgR8.mp4"
},
{
"bitrate":832000,
"content_type":"video/webm",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/640x360/FfLYyLagrUn8VGgy.webm"
},
{
"bitrate":832000,
"content_type":"video/mp4",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/vid/640x360/FfLYyLagrUn8VGgy.mp4"
},
{
"content_type":"application/x-mpegURL",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/pl/cXSu_jFCOj5Wcte5.m3u8"
},
{
"content_type":"application/dash+xml",
"url":"https://video.twimg.com/ext_tw_video/690629837333999617/pu/pl/cXSu_jFCOj5Wcte5.mpd"
}
]
}
}
]
},
"favorited":false,
"retweeted":false,
"possibly_sensitive":false,
"filter_level":"low",
"lang":"en",
"timestamp_ms":"1454636187971"
}
您需要调整访问元素的方式。我已经使用了您提供的JSON，将其存储在文件中，并使用jar进行jackson-core@2.7.0，jackson-annotation@2.7.0，从这里maven repo jackson-databind@2.7.0将它们导入到我的项目中，build path在eclipse中作为external jars。
我调整了对以下full_name的访问：
//Get the full name
String fullName = root.path("retweeted_status").path("place").path("full_name").asText();
并关注coordinates
//Get the coordinate array
JsonNode coordinates = root.path("retweeted_status").path("place").path("bounding_box").path("coordinates").get(0);
然后访问整个坐标，如下所示：
//print the whole array of array
System.out.println(coordinates.toString());
//output: [[-122.514926,37.708075],[-122.514926,37.833238],[-122.357031,37.833238],[-122.357031,37.708075]]
要单独访问坐标，请执行以下操作：
//print individual arrays, where each is lat and long
System.out.println(coordinates.get(0));
//output: [-122.514926,37.708075]
System.out.println(coordinates.get(1));
//output: [-122.514926,37.833238]
System.out.println(coordinates.get(2));
//output: [-122.357031,37.833238]
System.out.println(coordinates.get(3));
//output: [-122.357031,37.708075]
要分别访问每个坐标lat和long，请执行以下操作：
//print lat and long of each array seperately
System.out.println(coordinates.get(0).get(0));
//output: -122.514926
System.out.println(coordinates.get(0).get(1));
//output: 37.708075
System.out.println(coordinates.get(1).get(0));
System.out.println(coordinates.get(1).get(1));
System.out.println(coordinates.get(2).get(0));
System.out.println(coordinates.get(2).get(1));
System.out.println(coordinates.get(3).get(0));
System.out.println(coordinates.get(3).get(1));
以下是整个代码，我用于测试目的，从文件中读取您的 JSON：
import java.io.File;
import java.io.IOException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
public class JacksonTest {
public static void main(String[] args) throws JsonParseException, IOException {
File file = new File("C:\test_java\jackson.json");
ObjectMapper mapper = new ObjectMapper();
JsonNode root = mapper.readTree(file);
//Get the full name
String fullName = root.path("retweeted_status").path("place").path("full_name").asText();
System.out.println("full_name: " + fullName);
//Get the coordinate array
JsonNode coordinates = root.path("retweeted_status").path("place").path("bounding_box").path("coordinates").get(0);
//print the whole array of array
System.out.println(coordinates.toString());
//print individual arrays, where each is lat and long
System.out.println(coordinates.get(0));
System.out.println(coordinates.get(1));
System.out.println(coordinates.get(2));
System.out.println(coordinates.get(3));
//print lat and long of each array seperately
System.out.println(coordinates.get(0).get(0));
System.out.println(coordinates.get(0).get(1));
System.out.println(coordinates.get(1).get(0));
System.out.println(coordinates.get(1).get(1));
System.out.println(coordinates.get(2).get(0));
System.out.println(coordinates.get(2).get(1));
System.out.println(coordinates.get(3).get(0));
System.out.println(coordinates.get(3).get(1));
}
}
这是运行时上述代码的输出：
full_name：加利福尼亚州旧金山
[[-122.514926,37.708075]，[-122.514926,37.833238]，[-122.357031,37.833238]，[-122.357031,37.708075]] [-122.514926,37.708075] [-122.514926,37.833238]
[-122.357031,37.833238] [-122.357031,37.708075]
-122.514926
37.708075
-122.514926
37.833238
-122.357031
37.833238
-122.357031
37.708075
我怀疑您的代码只需要处理边界框的额外数组
见 https://dev.twitter.com/overview/api/places
坐标：浮点数组
。
边界框数组包装在一个附加数组中，以便与多边形表示法兼容。