- 一、遇到的问题：
- 二、使用递归遍历json查找key所在json对象
- 三、测试：
要获取的key在json不确定的层级位置，例如下面三个JSON，其中的 blackAttach 分别出现在不同的地方。因为blackAttach这个key可能会出现在不同的JSON层级对象中，所以就很难解析。
json1.json如下:
{
"datasource": [],
"ui": {
"id": "rootpanel",
"type": "rootpanel",
"blackAttach": "blackAttach_json1",
"allowAttach": "txt",
"children": [{
"id": "flexpanel1",
"type": "flexpanel",
"events": {},
"properties": {
"title": "flexpanel"
}
}]
},
"version": "1",
"title": "55",
"pageType": "nav"
}
json2.json如下:
{
"datasource": [],
"ui": {
"id": "rootpanel",
"type": "rootpanel",
"children": [{
"children": [{
"id": "panel1",
"children": [{
"id": "cardpanel1",
"events": {},
"properties": [{
"name": "field2",
"value": "$NULL"
},
{
"blackAttach": "blackAttach_json2",
"allowAttach": "txt"
}
],
"children": []
}]
}]
}]
},
"version": "1"
}
json3.json如下:
{
"datasource": [],
"ui": {
"children": [{
"id": "flexpanel1",
"events": {},
"properties": {
"title": "flexpanel"
},
"children": [{
"id": "panel1",
"blackAttach": "blackAttach_json3",
"allowAttach": "txt",
"children": [{
"id": "cardpanel1",
"type": "cardpanel",
"events": {},
"properties": {
"staticAttr": [{
"name": "field1",
"value": "$NULL"
}]
},
"children": []
}]
}]
}]
}
}
二、使用递归遍历json查找key所在json对象
1.用到的fastjson依赖 maven如下:
com.alibaba fastjson 1.2.79
2.使用 JsonSearch 工具类来递归遍历整个 json 查找目标 key 所在的 json 返回
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import java.util.Map;
public class JsonSearch {
public static JSONObject findKey(JSONObject jsonObject, String searchKey) {
JSONObject result = null;
for (Map.Entry entry : jsonObject.entrySet()) {
Object key = entry.getKey();
Object value = entry.getValue();
if (value instanceof JSONArray) {
result = handleArray((JSONArray) value, searchKey);
}
if (value instanceof JSONObject) {
result = handleJsonObject((JSONObject) value, searchKey);
}
if (result != null) {
return result;
}
}
return null;
}
public static JSONObject findKey(String jsonStr, String searchKey) {
return findKey(JSONObject.parseObject(jsonStr), searchKey);
}
public static JSONObject handleArray(JSONArray array, String searchKey) {
JSONObject result = null;
for (int i = 0; i < array.size(); i++) {
Object object = array.get(i);
if (object instanceof JSONArray) {
//递归查询
result = handleArray((JSONArray) object, searchKey);
}
if (object instanceof JSONObject) {
result = handleJsonObject((JSONObject) object, searchKey);
}
if (result != null) {
return result;
}
}
return null;
}
public static JSONObject handleJsonObject(JSONObject jsonObject, String searchKey) {
JSONObject result = null;
for (Map.Entry entry : jsonObject.entrySet()) {
Object key = entry.getKey();
Object value = entry.getValue();
if (value instanceof JSONArray) {
result = handleArray((JSONArray) value, searchKey);
}
if (value instanceof JSONObject) {
//递归查询
result = handleJsonObject((JSONObject) value, searchKey);
}
if (result != null) {
return result;
}
if (value instanceof String) {
if (searchKey != null && searchKey.equals(key)) {
return jsonObject;
}
}
}
return null;
}
}
三、测试：
public class MainServer {
public static void main(String[] args) throws Exception {
//获取json1文件内容
String filePath1 = "F:\json\json1.json";
String fileContent1 = new String(Files.readAllBytes(Paths.get(filePath1)), StandardCharsets.UTF_8);
//json字符串中查找blackAttach所在的json对象返回
JSONObject jsonObject1 = JsonSearch.findKey(fileContent1, "blackAttach");
System.out.println("json1中包含blackAttach的JSON：" + jsonObject1);
System.out.println("json1中的blackAttach：" + jsonObject1.getString("blackAttach"));
System.out.println();
//获取json2文件内容
String filePath2 = "F:\json\json2.json";
String fileContent2 = new String(Files.readAllBytes(Paths.get(filePath2)), StandardCharsets.UTF_8);
//json字符串中查找blackAttach所在的json对象返回
JSONObject jsonObject2 = JsonSearch.findKey(fileContent2, "blackAttach");
System.out.println("json3中包含blackAttach的JSON：" + jsonObject2);
System.out.println("json3中的blackAttach：" + jsonObject2.getString("blackAttach"));
System.out.println();
//获取json3文件内容
String filePath3 = "F:\json\json3.json";
String fileContent3 = new String(Files.readAllBytes(Paths.get(filePath3)), StandardCharsets.UTF_8);
//json字符串中查找blackAttach所在的json对象返回
JSONObject jsonObject3 = JsonSearch.findKey(fileContent3, "blackAttach");
System.out.println("json3中包含blackAttach的JSON：" + jsonObject3);
System.out.println("json3中的blackAttach：" + jsonObject3.getString("blackAttach"));
}
}
输出：
json1中包含blackAttach的JSON：{"allowAttach":"txt","children":[{"id":"flexpanel1","type":"flexpanel","events":{},"properties":{"title":"flexpanel"}}],"id":"rootpanel","type":"rootpanel","blackAttach":"blackAttach_json1"}
json1中的blackAttach：blackAttach_json1
json3中包含blackAttach的JSON：{"allowAttach":"txt","blackAttach":"blackAttach_json2"}
json3中的blackAttach：blackAttach_json2
json3中包含blackAttach的JSON：{"allowAttach":"txt","children":[{"children":[],"id":"cardpanel1","type":"cardpanel","events":{},"properties":{"staticAttr":[{"name":"field1","value":"$NULL"}]}}],"id":"panel1","blackAttach":"blackAttach_json3"}
json3中的blackAttach：blackAttach_json3
