json如何解析混合数组对象到实体类的list集合里去

一、前言

这次项目中遇到了一个这样的需求，把下面数据解析到我下面的对象里去。

json 文件

[
    {
        "categories": [
            "美食，小吃快餐"
        ],
        "coordinate": {
            "address": "王府井大街138号新东安广场3层328",
            "area": "东安市场",
            "area_id": "jk238eewf0k",
            "city": "北京市",
            "city_code": "110100",
            "district": "东城区",
            "district_code": "110101",
            "floor": "3",
            "latitude": "39.91456",
            "longitude": "116.41155",
            "province": "北京市",
            "province_code": "110000"
        },
        "name": "探鱼",
        "phone": "010-65280328",
        "poi_id": "d7s8f6s6212"
    },
    {
        "categories": [
            "美食，面包甜点"
        ],
        "coordinate": {
            "address": "丰台北路18号院恒泰广场f6楼",
            "area": "恒泰广场",
            "area_id": "ji8sgg3b32o",
            "city": "北京市",
            "city_code": "110100",
            "district": "丰台区",
            "district_code": "110106",
            "floor": "6",
            "latitude": "39.86608",
            "longitude": "116.30516",
            "province": "北京市",
            "province_code": "110000"
        },
        "name": "好客来",
        "phone": "010-65280221",
        "poi_id": "3g97sg8sd67"
    }
]

实体对象：

public class locatordata {
    // 分类
    private string categories;
    // 商圈
    private string area;
    // 商圈id
    private string areaid;
    // 省份
    private string province;
    // 省份code
    private string provincecode;
    // 城市
    private string city;
    // 城市code
    private string citycode;
    // 区县
    private string district;
    // 区县code
    private string districtcode;
    // 楼层
    private string floor;
    // 经度
    private double latitude;
    // 维度
    private double longitude;
    // 店铺名称
    private string name;
    // 店铺地址
    private string address;
    // 店铺电话
    private string phone;
    // 店铺id
    private string poiid;
}

不知道小伙伴有没有发现，我这里只是一个对象，没有一对多的关系哈，要的就是这样的效果。

但 json 文件里有个 coordinate 对象，而我实体对象不需要这个字段。那也没关系，一步步解析就完事了。

@restcontroller
public class parsecontroller {
	private static final logger logger = loggerfactory.getlogger(easyexcelcontroller.class);
	
	@postmapping(value = "/arrayobjectnestingparse",produces = "application/json;charset=utf-8")
    public returnt<string> arrayobjectnestingparse(@requestparam(value = "jsonfile") multipartfile jsonfile) {
        if (jsonfile == null) {
            return new returnt<>(returnt.bad_request, "params can not be null");
        }
        inputstream is = null;
        bufferedreader br = null;
        stringbuffer sb = new stringbuffer();
        string str = null;
        try {
            is = jsonfile.getinputstream();
            br = new bufferedreader(new inputstreamreader(is));
            while ((str = br.readline()) != null) {
                sb.append(str);
            }
        } catch (ioexception e) {
            e.printstacktrace();
        } finally {
            try {
                br.close();
            } catch (ioexception e) {
                e.printstacktrace();
            }
        }
        list<locatordata> locatordatalist = new arraylist<>();
        jsonarray jsonarray = jsonarray.parsearray(sb.tostring());
        for (int i = 0; i < jsonarray.size(); i++) {
            locatordata locatordata = new locatordata();
            jsonobject jsonobject = jsonarray.getjsonobject(i);
            string categories = jsonobject.getstring("categories");
            string coordinate = jsonobject.getstring("coordinate");
            jsonobject coordinateobj = jsonobject.parseobject(coordinate);
            string address = coordinateobj.getstring("address");
            string area = coordinateobj.getstring("area");
            string areaid = coordinateobj.getstring("area_id");
            string city = coordinateobj.getstring("city");
            string citycode = coordinateobj.getstring("city_code");
            string district = coordinateobj.getstring("district");
            string districtcode = coordinateobj.getstring("district_code");
            string floor = coordinateobj.getstring("floor");
            string latitude = coordinateobj.getstring("latitude");
            string longitude = coordinateobj.getstring("longitude");
            string province = coordinateobj.getstring("province");
            string provincecode = coordinateobj.getstring("province_code");
            string name = jsonobject.getstring("name");
            string phone = jsonobject.getstring("phone");
            string poiid = jsonobject.getstring("poi_id");
            locatordata.setcategories(categories);
            locatordata.setaddress(address);
            locatordata.setarea(area);
            locatordata.setareaid(areaid);
            locatordata.setprovince(province);
            locatordata.setprovincecode(provincecode);
            locatordata.setcity(city);
            locatordata.setcitycode(citycode);
            locatordata.setdistrict(district);
            locatordata.setdistrictcode(districtcode);
            locatordata.setfloor(floor);
            locatordata.setlatitude(double.parsedouble(latitude));
            locatordata.setlongitude(double.parsedouble(longitude));
            locatordata.setname(name);
            locatordata.setphone(phone);
            locatordata.setpoiid(poiid);
            locatordatalist.add(locatordata);
        }
        logger.info("locatordatalist: " + json.tojsonstring(locatordatalist));
        return new returnt<>(returnt.success, json.tojsonstring(locatordatalist));
    }
}

日志打印：

2020-01-07 00:39:30.284 [http-nio-8080-exec-3] info c.r.springbootdemo.controller.easyexcelcontroller-locatordatalist: [{"address":"王府井大街138号新东安广场3层328","area":"东安市场","areaid":"jk238eewf0k","categories":"[\"美食，小吃快餐\"]","city":"北京市","citycode":"110100","district":"东城区","districtcode":"110101","floor":"3","latitude":39.91456,"longitude":116.41155,"name":"探鱼","phone":"010-65280328","poiid":"d7s8f6s6212","province":"北京市","provincecode":"110000"},{"address":"丰台北路18号院恒泰广场f6楼","area":"恒泰广场","areaid":"ji8sgg3b32o","categories":"[\"美食，面包甜点\"]","city":"北京市","citycode":"110100","district":"丰台区","districtcode":"110106","floor":"6","latitude":39.86608,"longitude":116.30516,"name":"好客来","phone":"010-65280221","poiid":"3g97sg8sd67","province":"北京市","provincecode":"110000"}]

我们用工具转换一下看的更清晰一点：

[
    {
        "address": "王府井大街138号新东安广场3层328",
        "area": "东安市场",
        "areaid": "jk238eewf0k",
        "categories": "["美食，小吃快餐"]",
        "city": "北京市",
        "citycode": "110100",
        "district": "东城区",
        "districtcode": "110101",
        "floor": "3",
        "latitude": 39.91456,
        "longitude": 116.41155,
        "name": "探鱼",
        "phone": "010-65280328",
        "poiid": "d7s8f6s6212",
        "province": "北京市",
        "provincecode": "110000"
    },
    {
        "address": "丰台北路18号院恒泰广场f6楼",
        "area": "恒泰广场",
        "areaid": "ji8sgg3b32o",
        "categories": "["美食，面包甜点"]",
        "city": "北京市",
        "citycode": "110100",
        "district": "丰台区",
        "districtcode": "110106",
        "floor": "6",
        "latitude": 39.86608,
        "longitude": 116.30516,
        "name": "好客来",
        "phone": "010-65280221",
        "poiid": "3g97sg8sd67",
        "province": "北京市",
        "provincecode": "110000"
    }
]

json数组和list集合转换总结

//方法一,将json解析后赋给单独的元素
string jstr="{'json':'jsonvalue','bool':true,'int':1,'double':'20.5'}";
jsonobject json=jsonobject.fromobject(jstr);
boolean bool=json.getboolean("bool");
int i=json.getint("int");
double d=json.getdouble("double");
string value=json.getstring("json");
system.out.println("bool="+string.valueof(bool)+"\tjson="+value+"\tint="+i+"\tdouble="+d);

//方法二,json对象和bean对象之间相互转换
//假如你是有一个bean对象
class user{
private string name;
private string psw;
//封装getter/setter省略
}
//把一个json对象变成user
string u="{'name':'sail331x','psw':'123456789'}";
//用user对象接收json中的元素
user user=(user)jsonobject.tobean(jsonobject.fromobject(u),user.class);
//把一个user变成json对象：
jsonobject juser=jsonobject.fromobject(user);
//json字符串jstr
string jstr=juser.tostring();

//方法三,json对象直接转list集合、list集合转json对象
//声明一个person 实体类：
import java.util.date;
public class person {
    string id;
    int age;
    string name;
    date birthday;
    //get,set方法省略
}
//测试json数据转换
import java.util.iterator;
import java.util.list;
import org.junit.test;
import net.sf.json.jsonarray;
import net.sf.json.jsonconfig;
public class jsontolist {
　　public static void main(string[] args) {
　　　　string json="[{'name':'zhuangsan','age':18},{'name':'lisi','age':20}]";
　　　　jsonarray jsonarray = jsonarray.fromobject(json);
　　　　system.out.println(jsonarray);
　　　　list list = (list)jsonarray.tocollection(jsonarray, person.class);
　　　　iterator it = list.iterator();
　　　　while(it.hasnext()){
　　　　　　person p = (person)it.next();
　　　　　　system.out.println(p.getage());
　　　　}
　　}
　　@test
　　public void jsontolist1(){
　　　　string json="[{'name':'zhuangsan','age':18},{'name':'lisi','age':20}]";
　　　　jsonarray jsonarray = jsonarray.fromobject(json);
　　　　system.out.println(jsonarray);
　　　　list list = (list)jsonarray.tolist(jsonarray, person.class);
　　　　iterator it = list.iterator();
　　　　while(it.hasnext()){
　　　　　　person p = (person)it.next();
　　　　　　system.out.println(p.getage());
　　　　}
　　}
　　@test
　　public void jsontolist2(){
　　　　string json="[{'name':'zhuangsan','age':20},{'name':'lisi','age':18}]";
　　　　jsonarray jsonarray = jsonarray.fromobject(json);
　　　　system.out.println(jsonarray);
　　　　system.out.println("------------");
　　　　list list = (list)jsonarray.tolist(jsonarray, new person(), new jsonconfig());
　　　　iterator it = list.iterator();
　　　　while(it.hasnext()){
　　　　　　person p = (person)it.next();
　　　　　　system.out.println(p.getage());
　　　　}
　　}
}
//将list对象转为json字符串数组：
import java.util.linkedlist;
import java.util.list;
import net.sf.json.jsonarray;
public class listtojson {
　　public static void main(string[] args) {
　　　　list list = new linkedlist();
　　　　for(int i=0;i<3;i++){
　　　　　　person p = new person();
　　　　　　p.setage(i);
　　　　　　p.setname("name"+i);
　　　　　　list.add(p);
　　　　}
　　jsonarray jsonarray = jsonarray.fromobject(list);
　　system.out.println(jsonarray);
　　}
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。