Java 读/写 json串中的数据内容
JSON简介
JSON，全名JavaScript Object Notation, 即“JS对象简谱”。JSON是一种轻量级的数据交换格式，其基于 ECMAScript（European Computer Manufacturers Association, 欧洲计算机协会制定的js规范）的一个子集，也是基于JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999的一个子集，采用完全独立于编程语言的文本格式来存储和表示数据。简洁和清晰的层次结构使得 JSON 成为理想的数据交换语言—— 易于人阅读和编写，同时也易于机器解析和生成，并有效地提升网络传输效率。
org.json.simple.JSONObject
写
读
读取格式如下所示的json串。
{
"errcode":0,
"errmsg":"ok",
"access_token":"ena_OvqtddoX7h-hVL9GlmgOYmKpLh1EakBMX2a_BCeJXg-M8bIMDtAwEL41-hVL_O1Kgjgu8MkEXVxGHrojWu83X7CQSx3YACJphVjF5UvAOl5jLBq-2pspOiBbA1Oi-r7p2lHZmYWg_063poofk5FXFsO41bogSROA2dT3fFXxb82KXKkmjkZG8kOphrmqWlrvnvzEVLo9-rMsvGn_Mw",
"expires_in":7200}
代码如下所示。
import org.json.simple.parser.JSONParser;
import org.json.simple.JSONObject;
String jsonString = “{
"errcode":0,"errmsg":"ok","access_token":"ena_OvqtddoX7h-hVL9GlmgOYmKpLh1EakBMX2a_BCeJXg-M8bIMDtAwEL41-hVL_O1Kgjgu8MkEXVxGHrojWu83X7CQSx3YACJphVjF5UvAOl5jLBq-2pspOiBbA1Oi-r7p2lHZmYWg_063poofk5FXFsO41bogSROA2dT3fFXxb82KXKkmjkZG8kOphrmqWlrvnvzEVLo9-rMsvGn_Mw","expires_in":7200}”
JSONParser jsonParser = new JSONParser();
JSONObject jsonObject = (JSONObject) jsonParser.parse(jsonString );
String errcode = jsonObject.get("errcode").toString();
String errmsg = jsonObject.get("errmsg").toString();
if (errcode.equals("0") && errmsg.equals("ok")) {
String resultFromGET_UrlString = jsonObject.get("access_token").toString();
System.out.println("请求企业微信的token结果是"+resultFromGET_UrlString);
}else {
System.out.println("请求返回信息报错");
}
com.alibaba.fastjson.JSONObject
写
读
读取格式如下所示的json串。
{
"code":0,
"message":"ok",
"body":{
"result": "success",
"status": "1"
}
}
代码如下所示。
import com.alibaba.fastjson.JSONObject;
String jsonString = "{
\"code\":0,\"message\":\"ok\",\"body\":{
\"result\": \"success\",\"status\": \"1\"}}";
JSONObject jsonObject = JSONObject.parseObject(jsonString);
String result = jsonObject.getJSONObject("body").getString("result");
String status = jsonObject.getJSONObject("body").getString("status");
//输出结果为“获取到Json中的result是success，status是1”
System.out.println("获取到Json中的result是"+result+"，status是"+status);
//也提供了读取jsonArray的方法
JSONArray eventList_jsonArray = testJsonObject.getJSONArray("eventList");
//读取eventList_jsonArray中的第一个元素中“courseCode”键值对
String courseCode = eventList_jsonArray.getJSONObject(0).getString("courseCode")
//读取JSONObject内层jsonArray中的jsonArray，自测
String testJsonString = "{
\"studentName\":\"1\",\"courseList\":[{
\"courseOrder\":\"1\",\"courseCode\":\"7E\",\"courseLenght\":\"39\",\"courseType\":\"3\",\"courseContentList\":[{
\"courseContentOrder\":1,\"courseContentValue\":\"01\"},{
\"courseContentOrder\":2,\"courseContentValue\":\"02\"},{
\"courseContentOrder\":3,\"courseContentValue\":\"03\"},{
\"courseContentOrder\":4,\"courseContentValue\":\"04\"},{
\"courseContentOrder\":5,\"courseContentValue\":\"05\"},{
\"courseContentOrder\":6,\"courseContentValue\":\"06\"},{
\"courseContentOrder\":7,\"courseContentValue\":\"07\"}]}]}";
JSONObject testJsonObject = JSONObject.parseObject(testJsonString);
JSONArray courseContentList_jsonArray = testJsonObject.getJSONArray("courseContentList");
for (Iterator<Object> iterator = courseContentList_jsonArray.iterator(); iterator.hasNext(); ) {
JSONObject tempJsonObject = (JSONObject) iterator.next();
JSONArray courseContentListJsonArray = tempJsonObject.getJSONArray("courseContentList");
System.out.println("courseContentList===>>> " + courseContentListJsonArray );
//int value = courseContentListJsonArray .getIntValue(i);//还可以通过此方法取出JsonArray中的第i个值
}
net.sf.json.JSONObject
写
import net.sf.json.JSONObject;
import net.sf.json.JSONArray;
//写
JSONArray dataarray = new JSONArray();
JSONArray childrenarray1 = new JSONArray();
JSONArray childrenarray2 = new JSONArray();
JSONArray childrenarray3 = new JSONArray();
JSONObject result = new JSONObject();
JSONObject datajson = new JSONObject();
JSONObject childrenjson1 = new JSONObject();
JSONObject childrenjson2 = new JSONObject();
JSONObject childrenjson3 = new JSONObject();
childrenjson3.put("LCode", "LCode");
childrenjson3.put("QName", "QName");
childrenjson3.put("OId", "66666666666666");
childrenjson3.put("Time", "expEndTime");
childrenjson3.put("Time", "111");
childrenjson3.put("type", "222");
childrenjson3.put("EBTime", "666");
childrenjson3.put("EId", "888");
childrenjson3.put("status", "已提交");
childrenarray3.add(childrenjson3);
childrenjson2.put("children", childrenarray3);
childrenarray2.add(childrenjson2);
childrenjson1.put("children", childrenarray2);
childrenarray1.add(childrenjson1);
datajson.put("children", childrenarray1);
dataarray.add(datajson);
result.put("data", dataarray);
读
读上述写的json串的代码如下所示。
//读
String testJsonString = "{"studentId":"1684","studentPropertyList":[{"studentOrder":"1","paramList":[{"paraOrder":1,"paraValue":"1"},{"paraOrder":2,"paraValue":"2"},{"paraOrder":3,"paraValue":"3"},{"paraOrder":4,"paraValue":"4"},{"paraOrder":5,"paraValue":"5"},{"paraOrder":6,"paraValue":"6"},{"paraOrder":7,"paraValue":"7"}]}]}";
JSONObject jsonObject = JSONObject.fromObject(testJsonString);//创建json对象
JSONArray jsonArray = jsonObject.getJSONArray("eventList");
for(int i=0;i<jsonArray.size();i++) {
JSONObject jsonObjectFromJsonArray = jsonArray.getJSONObject(i);
JSONArray paramListJsonArray = jsonObjectFromJsonArray.getJSONArray("paramList");//取出paramList
}
//读，另一例子
String QNameString = (String) result.getJSONArray("data").getJSONObject(0).getJSONArray("children").getJSONObject(0).getJSONArray("children").getJSONObject(0).getJSONArray("children").getJSONObject(0).getString("QName");
System.out.println("从json中取出的QName是："+QNameString );