Java解析json字符串（二）

上篇踩坑了Java解析json字符串直接解析的方式，這篇踩一下解析成javabean的方式的坑兒~還是分三種方式來，先上jsonlib的解析方式~

一、JsonLib

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class jsonLibToJavaBean {
    public static void main(String[] args) {
        //先來個最簡單的json栗子
        String json = "{'continent': '亞洲','country': '中國'}";   //需要建立對應entity
        JSONObject jsonObject = JSONObject.fromObject(json);
        Continent ci = (Continent) JSONObject.toBean(jsonObject, Continent.class);
	System.out.println("continent:" + ci.getContinent() + "," + "country:" + ci.getCountry());
        輸出：continent:亞洲,country:中國
        System.out.println("====================");

        //json數組
        String json = "[{'continent': '亞洲','country': '中國'},{'continent': '亞洲','country': '中國'}]";
        JSONArray jsonArray = JSONArray.fromObject(json);
	List<Object> list = JSONArray.fromObject(jsonArray);
	for (int i = 0; i < list.size(); i++) {
	    JSONObject jsonObject = JSONObject.fromObject(list.get(i));
	    Continent ci = (Continent) JSONObject.toBean(jsonObject, Continent.class);
	    System.out.println("continent:" + ci.getContinent() + "," + "country:" + ci.getCountry());
	}
        /*
	 * 控制檯輸出
	 * continent:亞洲,country:中國
	 * continent:亞洲,country:中國
	 */
    }
}

//實體類
public class Continent {
    private String continent;
    private String country;
    public String getContinent() {
        return continent;
    }
    public void setContinent(String continent) {
	this.continent = continent;
    }
    public String getCountry() {
	return country;
    }
    public void setCountry(String country) {
	this.country = country;
    }
}

import java.util.List;
import entity.NationalSchool;
import entity.Province;
import net.sf.json.JSONObject;

public class jsonLibToJavaBean {
    public static void main(String[] args) {
        //下面來個複雜點的栗子，json中帶複雜數據的，例如list、map等
        String json = "{'country': '中國','province': [{'city': '西安','postoffice': '012345'},{'city': '洛陽','postoffice': '012345'}]}";
	JSONObject jsonObject = JSONObject.fromObject(json);
	NationalSchool ns = (NationalSchool) JSONObject.toBean(jsonObject, NationalSchool.class);
	String country = ns.getCountry();
	System.out.println(country);
	List<Province> list = ns.getProvince();
	for (int i = 0; i < list.size(); i++) {
	    JSONObject jb = JSONObject.fromObject(list.get(i));
	    Province p = (Province) JSONObject.toBean(jb, Province.class);
	    System.out.println("city:" + p.getCity() + "," + "postoffice:" + p.getPostoffice());
	}

        //令一種寫法
        Map map = new HashMap();
	map.put("province", Province.class);
	JSONObject jsonObject = JSONObject.fromObject(json);
	NationalSchool ns = (NationalSchool) JSONObject.toBean(jsonObject, NationalSchool.class, map);
	String country = ns.getCountry();
	System.out.println(country);
	List<Province> list = ns.getProvince();
	for (int i = 0; i < list.size(); i++) {
	    System.out.println("city:" + list.get(i).getCity() + "," + "postoffice:" + list.get(i).getPostoffice());
	}

        /*
	 * 兩種寫法的控制檯輸出
	 * 中國
	 * city:西安,postoffice:012345
	 * city:洛陽,postoffice:012345
	 */

        /*
	 * 下面的這種寫法可以不用像上面那樣進行兩次轉換javabean
	 * 對於剛接觸json轉對象這方面的學生可能會有那麼一點繞
	 * 這樣可以規避一個錯誤，如果直接這樣寫的話：
	 * NationalSchool ns = (NationalSchool) JSONObject.toBean(jsonObject, NationalSchool.class);
	 * List<Province> list = ns.getProvince();
	 * 直接輸出list是可以的，控制檯輸出
	 * [net.sf.ezmorph.bean.MorphDynaBean@161cd475[
	 * 		{postoffice=012345, city=西安}
	 * ], net.sf.ezmorph.bean.MorphDynaBean@532760d8[
	 * 		{postoffice=012345, city=洛陽}
         * ]]
         *
	 * 但是遍歷list時會報錯：
	 * net.sf.ezmorph.bean.MorphDynaBean cannot be cast to xxx
	 */
    }
}

//對應實體類
public class NationalSchool implements Serializable {
    private static final long serialVersionUID = 1L;
    private String country;
    private List<Province> province;
    public String getCountry() {
	return country;
    }
    public void setCountry(String country) {
	this.country = country;
    }
    public List<Province> getProvince() {
	return province;
    }
    public void setProvince(List<Province> province) {
	this.province = province;
    }
}

public class Province implements Serializable {
    private static final long serialVersionUID = 1L;
    private String city;
    private String postoffice;
    private boolean capital;
    public String getCity() {
	return city;
    }
    public void setCity(String city) {
	this.city = city;
    }
    public String getPostoffice() {
	return postoffice;
    }
    public void setPostoffice(String postoffice) {
	this.postoffice = postoffice;
    }
    public boolean isCapital() {
	return capital;
    }
    public void setCapital(boolean capital) {
	this.capital = capital;
    }
    public static long getSerialversionuid() {
	return serialVersionUID;
    }
}

二、FastJson：親身體驗在轉複雜json字符串的時候比JsonLib好用，實體類就不貼了都在上面了，直接貼邏輯代碼

import java.util.List;

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import entity.Continent;
import entity.NationalSchool;
import entity.Province;

public class fastJsonToJavaBean {
    public static void main(String[] args) {
        //字符串
        String json = "{'continent': '亞洲','country': '中國'}";
        JSONObject jsonObject = JSONObject.parseObject(json);
        Continent ci = JSONObject.toJavaObject(jsonObject, Continent.class);
    	System.out.println("continent:" + ci.getContinent() + "," + "country:" + ci.getCountry());
        System.out.println("==============================");

        //json數組
        String jsons = "[{'continent': '亞洲','country': '中國'},{'continent': '亞洲','country': '中國'}]";
        JSONArray jsonArray = JSONArray.parseArray(jsons);
        for (int i = 0; i < jsonArray.size(); i++) {
            JSONObject jsonObjects = JSONObject.parseObject(jsonArray.get(i).toString());
            Continent cis = JSONObject.toJavaObject(jsonObjects, Continent.class);
            System.out.println("continent:" + cis.getContinent() + "," + "country:" + cis.getCountry());
        }
        System.out.println("==============================");

        //複雜json
        String jsonss = "{'country': '中國','province': [{'city': '西安','postoffice': '012345'},{'city': '洛陽','postoffice': '012345'}]}";
        JSONObject jsonObjectss = JSONObject.parseObject(jsonss);
        NationalSchool ns = JSONObject.toJavaObject(jsonObjectss, NationalSchool.class);
        String country = ns.getCountry();
        System.out.println("country:" + country);
        List<Province> list = ns.getProvince();
        for (int j = 0; j < list.size(); j++) {
            System.out.println("city:" + list.get(j).getCity() + "," + "postoffice:" + list.get(j).getPostoffice());
        }
        System.out.println("==============================");
        /*
         * FastJson和JsonLib的不同之處就在這裏了
         * 這裏對於province可以直接轉成list，而JsonLib不事先把Province對象放到map裏
         * 會直接報錯，或者就是像JsonLib中第一種方法分層解析複雜json字符串
         * 推薦使用FastJson
         */

        /*
         * 控制檯輸出
         * continent:亞洲,country:中國
         * ==============================
         * continent:亞洲,country:中國
         * continent:亞洲,country:中國
         * ==============================
         * country:中國
         * city:西安,postoffice:012345
         * city:西安,postoffice:012345
         */

        //來個json數組練練手
        String jsonsss = "[{'country': '中國','province': [{'city': '西安','postoffice': '012345'},{'city': '洛陽','postoffice': '012345'}]},{'country': '中國','province': [{'city': '西安','postoffice': '012345'},{'city': '洛陽','postoffice': '012345'}]}]";
        JSONArray jsonArrays = JSONArray.parseArray(jsonsss);
        for (int k = 0; k < jsonArrays.size(); k++) {
            JSONObject jsonObjectsss = JSONObject.parseObject(jsonArrays.get(k).toString());
            NationalSchool nss = JSONObject.toJavaObject(jsonObjectsss, NationalSchool.class);
            String countrys = ns.getCountry();
            System.out.println("country:" + countrys);
            List<Province> lists = nss.getProvince();
            for (int j = 0; j < lists.size(); j++) {
                System.out.println("city:" + lists.get(j).getCity() + "," + "postoffice:" + lists.get(j).getPostoffice());
            }
        }
    }
}

三、Gson

import java.util.List;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.reflect.TypeToken;

import entity.Continent;
import entity.NationalSchool;
import entity.Province;

public class gsonToJavaBean {
    public static void main(String[] args) {
        String json = "{'continent': '亞洲','country': '中國'}";
	Gson gson = new Gson();
	Continent ci = gson.fromJson(json, Continent.class);
	System.out.println("continent:" + ci.getContinent() + "," + "country:" + ci.getCountry());
        System.out.println("==============================");

        String jsons = "[{'continent': '亞洲','country': '中國'},{'continent': '亞洲','country': '中國'}]";
        Gson gsons = new Gson();
        List<Continent> list = (List<Continent>) gsons.fromJson(jsons, new TypeToken<List<Continent>>(){}.getType());
        for (int i = 0; i < list.size(); i++) {
            System.out.println("continent:" + list.get(i).getContinent() + "," + "country:" + list.get(i).getCountry());
        }
        System.out.println("另一種方法");
        JsonArray jsonArray = new JsonParser().parse(jsons).getAsJsonArray();
        for (int i = 0; i < jsonArray.size(); i++) {
            JsonObject jsonObject = (JsonObject) new JsonParser().parse(jsonArray.get(i).toString());
            System.out.println("continent:" + jsonObject.get("continent").getAsString() + "," + "country:" + jsonObject.get("country").getAsString());
        }
        System.out.println("==============================");

        String jsonss = "{'country': '中國','province': [{'city': '西安','postoffice': '012345'},{'city': '洛陽','postoffice': '012345'}]}";
        Gson gsonss = new Gson();
        NationalSchool ns = gsonss.fromJson(jsonss, NationalSchool.class);
        System.out.println(ns.getCountry());
        List<Province> listp = ns.getProvince();
        for (int j = 0; j < listp.size(); j++) {
            System.out.println("city:" + listp.get(j).getCity() + "," + "postoffice:" + listp.get(j).getPostoffice());
        }

	/*
	 * 控制檯輸出
	 * continent:亞洲,country:中國
	 * ==============================
	 * continent:亞洲,country:中國
	 * continent:亞洲,country:中國
	 * 另一種方法
	 * continent:亞洲,country:中國
	 * continent:亞洲,country:中國
	 * ==============================
	 * 中國
	 * city:西安,postoffice:012345
	 * city:西安,postoffice:012345
	 */
    }
}

未完待續...