常用：String转Json

JSONObject json = JSONObject.parseObject(token);
token = json.get("token").toString();

一、实体转Json Json转实体 String转Json String转JSONArray

一、JDKjson(json-lib-2.4-jdk15.jar)
//String转Json
JSONObject json= JSONObject.fromObject(responseMsg);//JSONObject解析
//String转JSONArray
JSONArray listJson = JSONArray.fromObject(responseMsg);//JSONArray解析 "[{},{},{}]"
//实体转Json
JSONObject json = JSONObject.fromObject(std);
//List转Json
JSONArray jsonArray = JSONArray.fromObject(list);
//Json转实体
StdCost stdTemp = (StdCost)JSONObject.toBean(json, StdCost.class);
//Json转List
List<StdCost> listTemp = JSONArray.toList(jsonArray, StdCost.class);二、阿里云fastjson(fastjson-1.2.10.jar)
//String转Json
JSONObject json = JSONObject.parseObject(responseMsg);//JSONObject解析
//String转JSONArray
JSONArray listJson = JSONArray.parseArray(responseMsg);//JSONArray解析 "[{},{},{}]"
//实体转Json
JSONObject json = (JSONObject)JSONObject.toJSON(std);
//List转Json
JSONArray jsonArray = (JSONArray)JSONArray.toJSON(list);
//Json转实体
StdCost stdJson = JSONObject.parseObject(json.toString(), StdCost.class);
//Json转List
List<StdCost> listTemp = JSONArray.parseArray(jsonArray.toString(), StdCost.class);

完整示例：

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S");
if(list != null && list.size() > 0){/*for(int i=0; i<list.size(); i++){StdCost std = list.get(i);System.out.println("--- " + i + "/" + list.size() +" " + std.getStudentName() +" " + std.getStudentIdCard() +" " + std.getFeitype() +" " + std.getFei() +" " + df.format(std.getCreatedDate()));JSONObject json = JSONObject.fromObject(std);listJson.add(json);StdCost stdTemp = (StdCost)JSONObject.toBean(json, StdCost.class);System.out.println(stdTemp.getStudentName() +" " + stdTemp.getStudentIdCard() +" " + stdTemp.getFeitype() +" " + stdTemp.getFei() +" " + df.format(stdTemp.getCreatedDate()));*//*JSONObject json = (JSONObject)JSONObject.toJSON(std);listJson.add(json);StdCost stdTemp = JSONObject.parseObject(json.toString(), StdCost.class);System.out.println(stdTemp.getStudentName() +" " + stdTemp.getStudentIdCard() +" " + stdTemp.getFeitype() +" " + stdTemp.getFei() +" " + df.format(stdTemp.getCreatedDate()));*///}//jsonArray = JSONArray.fromObject(list);//List<StdCost> listTemp = JSONArray.toList(jsonArray, StdCost.class);jsonArray = (JSONArray)JSONArray.toJSON(list);List<StdCost> listTemp = JSONArray.parseArray(jsonArray.toString(), StdCost.class);if(listTemp != null && listTemp.size() > 0){StdCost stdTemp = null;for(int i=0; i<listTemp.size(); i++){stdTemp = listTemp.get(i);System.out.println(stdTemp.getStudentName() +" " + stdTemp.getStudentIdCard() +" " + stdTemp.getFeitype() +" " + stdTemp.getFei() +" " + df.format(stdTemp.getCreatedDate()));}}
}

二、String转Json(Sting转JSONObject) 及 String转JsonArray(Sting转JSONArray)

1）普通net.sf.json.JSONObject

JSONObject json= JSONObject.fromObject(responseMsg);//JSONObject解析
JSONArray listJson = JSONArray.fromObject(responseMsg);//JSONArray解析 "[{},{},{}]"

完整示例：

//6.处理返回的内容
//JSONObject json= JSONObject.fromObject(responseMsg);//JSONObject解析
JSONArray listJson = JSONArray.fromObject(responseMsg);//JSONArray解析 "[{},{},{}]"
for(int i=0; i<listJson.size(); i++){JSONObject jsonObject = listJson.getJSONObject(i);String canteenName = jsonObject.getString("canteenName");String employeeName = jsonObject.getString("employeeName");System.out.println("canteenName:" + canteenName);System.out.println("employeeName:" + employeeName);
}

2）阿里云fastjson

//String转Json
JSONObject json = JSONObject.parseObject(token);//JSONObject解析
//String转JSONArray
JSONArray listJson = JSONArray.parseArray(value);//JSONArray解析 "[{},{},{}]"

  

三、json中带反斜杠\无法解析的问题

普通net.sf.json.JSONObject

import net.sf.json.JSONObject;String jsonStr = "{\"name\":\"zhangsan\",\"password\":\"123123\"}";
JSONObject json_test = JSONObject.fromObject(jsonStr);

解决json中带反斜杠\无法解析的问题(手工处理) 

//解决json中带反斜杠\无法解析的问题(手工处理)
jsonStr = jsonStr.substring(1, jsonStr.length() - 1);
jsonStr = jsonStr.replace("\\", "");

阿里云fastjson

String xmlStr = {"xmlStr":"<?xml version=\"1.0\" encoding=\"UTF-8\"?><APPROVEDATAINFO><SBLSH_SHORT>405051610052012121110300001</SBLSH_SHORT><SXBM>52012120140505161008008244</SXBM><XZQHDM>520100</XZQHDM><EXPRESSTYPE>3</EXPRESSTYPE></APPROVEDATAINFO>"};
JSONObject json = JSONObject.parseObject(xmlStr);
String xml = json.get("xmlStr").toString();
System.out.println(xml);

解决json中带反斜杠\无法解析的问题(阿里云fastjson) 

//解决json中带反斜杠\无法解析的问题(阿里云fastjson)
jsonStr = JSON.parse(jsonStr).toString();

 参考：问题关于json 字符串中带有反斜杠的问题_ベ远行ミ的博客-CSDN博客_json里面有反斜杠

Java JSON转Map 

//JSON转Map(JSONObject是Map接口的一个实现类)
Map json = (Map)JSONObject.parse(str);

 参考：Java JSON转换为map_Eric-x的博客-CSDN博客_java json转map