Java 实体转Json Json转实体 String转Json Sting转JSONObject Sting转JSONArray_java 实体类转json

常用：String转Json 字符串转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

最新示例 (Redis缓存)

Json转实体

// 保存第一页的电子档案信息(Redis缓存中)
// 获取缓存的第一页数据
String key1 = RedisConstant.PREFIX_DOCUMENT + CurrentUserUtil.getCurrentUserInfo().getUserId() + ":" + dto.getSceneId() + ":" + 1;
String jsonStr = redisTemplate.opsForValue().get(key1);
if(!StringUtils.isEmpty(jsonStr)){
    // Json转实体
    BusinessDto businessDto = JSONObject.parseObject(jsonStr, BusinessDto.class);
    if(!CollectionUtils.isEmpty(businessDto.getDocuments())){
    }
}

 Json转List

// 优化，增加Redis缓存
String key = RedisConstant.PREFIX_ORG_LISTTREE +
        (id == null ? "default-" : id + "-") +
        (type == null ? "default-" : type + "-") +
        (StringUtils.isEmpty(name) ? "default" : name);
String jsonStr = redisTemplate.opsForValue().get(key);
if(!StringUtils.isEmpty(jsonStr)){
    // Json转List
    List<SysOrganizationVo> listReturn = JSONArray.parseArray(jsonStr, SysOrganizationVo.class);
}

实体转Json 

// 实体转Json
JSONObject json = (JSONObject) JSONObject.toJSON(businessDto);
// 保存到Redis
redisTemplate.opsForValue().set(RedisConstant.PREFIX_DOCUMENT + CurrentUserUtil.getCurrentUserInfo().getUserId() + ":" + businessDto.getSceneId() + ":" + businessDto.getWhichPage(), json.toString());

List转Json

// List转Json
JSONArray jsonArray = (JSONArray)JSONArray.toJSON(list);
// 保存到Redis
redisTemplate.opsForValue().set(key, jsonArray.toString());