Json文件例子:java
1 { 2 "type": "Update", 3 "data": { 4 "temp": "v", 5 "Name": "tttt", 6 "Id": 5, 7 "template": { 8 "head": { 9 "headtext": " " 10 }, 11 "body": { 12 "bodytext": { 13 "1": "123456789" 14 }, 15 "image": { 16 "2": 169000 17 } 18 }, 19 "tag": { 20 "1": { 21 "image": { 22 "normal": 179000 23 }, 24 "back": { 25 "normal": 180000 26 }, 27 "state": true 28 } 29 } 30 } 31 } 32 }
代碼:json
1 package com.test.java; 2 3 import java.io.BufferedReader; 4 import java.io.File; 5 import java.io.FileNotFoundException; 6 import java.io.FileReader; 7 import java.io.IOException; 8 import java.util.HashSet; 9 import java.util.Iterator; 10 11 import org.json.JSONException; 12 import org.json.JSONObject; 13 14 public class FindKeyInJson { 15 16 static String stringInJSON = null; 17 18 public static void main(String[] args) { 19 20 File jsonFile = new File( 21 "D:\\jsonexample.txt"); 22 StringBuffer sb = new StringBuffer(); 23 try (BufferedReader br = new BufferedReader(new FileReader(jsonFile))) { 24 String line = null; 25 while ((line = br.readLine()) != null) { 26 sb.append(line); 27 } 28 } catch (FileNotFoundException e) { 29 // TODO Auto-generated catch block 30 e.printStackTrace(); 31 } catch (IOException e) { 32 // TODO Auto-generated catch block 33 e.printStackTrace(); 34 } 35 36 try { 37 System.out.println(sb.toString()); 38 JSONObject jo = new JSONObject(sb.toString()); 39 String content = getKeyString(jo, "bodytext");//獲取bodytext字段信息 40 System.out.println(content); 41 } catch (JSONException e) { 42 // TODO Auto-generated catch block 43 e.printStackTrace(); 44 } 45 46 } 47 48 public static String getKeyString(JSONObject json, String key) { 49 HashSet<String> hSet = new HashSet<String>(); 50 51 if (json.has(key)) { 52 // 在當前的層次中存在指定的key,能夠直接獲取指定key對應的string 53 try { 54 stringInJSON = json.get(key).toString(); 55 } catch (JSONException e) { 56 e.printStackTrace(); 57 } 58 } else { 59 // 在當前的層次中不存在指定的key,須要往下一個層次查找 60 hSet = getKeySetOnJSON(json);// 獲取當前層次的全部key 61 Iterator<String> iterator = hSet.iterator(); 62 while (iterator.hasNext()) { 63 String i = iterator.next(); 64 if (isJSONObject(json, i)) { 65 try { 66 JSONObject tp = (JSONObject) json.get(i); 67 HashSet<String> hSet2 = new HashSet<String>(); 68 hSet2 = getKeySetOnJSON(tp); 69 if (tp.has(key)) { 70 stringInJSON = tp.get(key).toString(); 71 break; 72 } else { 73 getKeyString(tp, key);// 開始遞歸 74 } 75 76 } catch (JSONException e) { 77 78 e.printStackTrace(); 79 } 80 } 81 } 82 } 83 return stringInJSON; 84 } 85 86 public static HashSet<String> getKeySetOnJSON(JSONObject json) { 87 HashSet<String> hSet = new HashSet<String>(); 88 Iterator<String> iterator = json.keys(); 89 while (iterator.hasNext()) { 90 String i = iterator.next(); 91 hSet.add(i); 92 } 93 return hSet; 94 } 95 96 public static boolean isJSONObject(JSONObject json, String key) { 97 boolean flag = false; 98 try { 99 try { 100 JSONObject tp = (JSONObject) json.get(key); 101 System.out.println(key + " is JSON Object"); 102 flag = true; 103 } catch (JSONException e) { 104 e.printStackTrace(); 105 } 106 } catch (ClassCastException e) { 107 System.out.println(key + " is not JSON Object"); 108 } 109 return flag; 110 } 111 112 }
result:app
1 { "type": "Update", "data": { "temp": "v", "Name": "tttt", "Id": 5, "template": { "head": { "headtext": " " }, "body": { "bodytext": { "1": "123456789" }, "image": { "2": 169000 } }, "tag": { "1": { "image": { "normal": 179000 }, "back": { "normal": 180000 }, "state": true } } } }} 2 data is JSON Object 3 template is JSON Object 4 head is JSON Object 5 headtext is not JSON Object 6 tag is JSON Object 7 1 is JSON Object 8 image is JSON Object 9 normal is not JSON Object 10 back is JSON Object 11 normal is not JSON Object 12 state is not JSON Object 13 body is JSON Object 14 temp is not JSON Object 15 Id is not JSON Object 16 Name is not JSON Object 17 type is not JSON Object 18 {"1":"123456789"} //最終結果