一、什麼是JSON？

JSON就是一串字串 只不過元素會使用特定的符號標註。

{} 雙括號表示物件

[] 中括號表示陣列

"" 雙引號內是屬性或值

: 冒號表示後者是前者的值(這個值可以是字串、數字、也可以是另一個數組或物件)

所以 {"name": "Michael"} 可以理解為是一個包含name為Michael的物件

而[{"name": "Michael"},{"name": "Jerry"}]就表示包含兩個物件的陣列

當然了,你也可以使用{"name":["Michael","Jerry"]}來簡化上面一部,這是一個擁有一個name陣列的物件

二、JSON解析之傳統的JSON解析

1、生成JSOn字串

public static String createJsonString(String key, Object value) {
		JSONObject jsonObject = new JSONObject();
		jsonObject.put(key, value);
		return jsonObject.toString();
	}

2、解析JSON字串

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.json.JSONArray;
import org.json.JSONObject;

import com.android.myjson.domain.Person;

/**
 * 完成對json資料的解析
 * 
 */
public class JsonTools {


	public static Person getPerson(String key, String jsonString) {
		Person person = new Person();
		try {
			JSONObject jsonObject = new JSONObject(jsonString);
			JSONObject personObject = jsonObject.getJSONObject("person");
			person.setId(personObject.getInt("id"));
			person.setName(personObject.getString("name"));
			person.setAddress(personObject.getString("address"));
		} catch (Exception e) {
			// TODO: handle exception
		}
		return person;
	}

	public static List getPersons(String key, String jsonString) {
		List list = new ArrayList();
		try {
			JSONObject jsonObject = new JSONObject(jsonString);
			// 返回json的陣列
			JSONArray jsonArray = jsonObject.getJSONArray(key);
			for (int i = 0; i < jsonArray.length(); i++) {
				JSONObject jsonObject2 = jsonArray.getJSONObject(i);
				Person person = new Person();
				person.setId(jsonObject2.getInt("id"));
				person.setName(jsonObject2.getString("name"));
				person.setAddress(jsonObject2.getString("address"));
				list.add(person);
			}
		} catch (Exception e) {
			// TODO: handle exception
		}
		return list;
	}

	public static List getList(String key, String jsonString) {
		List list = new ArrayList();
		try {
			JSONObject jsonObject = new JSONObject(jsonString);
			JSONArray jsonArray = jsonObject.getJSONArray(key);
			for (int i = 0; i < jsonArray.length(); i++) {
				String msg = jsonArray.getString(i);
				list.add(msg);
			}
		} catch (Exception e) {
			// TODO: handle exception
		}
		return list;
	}

	public static List> listKeyMaps(String key,
			String jsonString) {
		List> list = new ArrayList>();
		try {
			JSONObject jsonObject = new JSONObject(jsonString);
			JSONArray jsonArray = jsonObject.getJSONArray(key);
			for (int i = 0; i < jsonArray.length(); i++) {
				JSONObject jsonObject2 = jsonArray.getJSONObject(i);
				Map map = new HashMap();
				Iterator iterator = jsonObject2.keys();
				while (iterator.hasNext()) {
					String json_key = iterator.next();
					Object json_value = jsonObject2.get(json_key);
					if (json_value == null) {
						json_value = "";
					}
					map.put(json_key, json_value);
				}
				list.add(map);
			}
		} catch (Exception e) {
			// TODO: handle exception
		}
		return list;
	}
}
 

三、JSON解析之GSON

1、生成JSON字串

import com.google.gson.Gson;

public class JsonUtils {

	public static String createJsonObject(Object obj) {
		Gson gson = new Gson();
		String str = gson.toJson(obj);
		return str;

	}
}

二、解析JSON

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

;
public class GsonTools {

	public GsonTools() {
		// TODO Auto-generated constructor stub
	}

	/**
	 * @param 
	 * @param jsonString
	 * @param cls
	 * @return
	 */
	public static  T getPerson(String jsonString, Class cls) {
		T t = null;
		try {
			Gson gson = new Gson();
			t = gson.fromJson(jsonString, cls);
		} catch (Exception e) {
			// TODO: handle exception
		}
		return t;
	}

	/**
	 * 使用Gson進行解析 List
	 * 
	 * @param 
	 * @param jsonString
	 * @param cls
	 * @return
	 */
	public static  List getPersons(String jsonString, Class cls) {
		List list = new ArrayList();
		try {
			Gson gson = new Gson();
			list = gson.fromJson(jsonString, new TypeToken>() {
			}.getType());
		} catch (Exception e) {
		}
		return list;
	}

	/**
	 * @param jsonString
	 * @return
	 */
	public static List getList(String jsonString) {
		List list = new ArrayList();
		try {
			Gson gson = new Gson();
			list = gson.fromJson(jsonString, new TypeToken>() {
			}.getType());
		} catch (Exception e) {
			// TODO: handle exception
		}
		return list;
	}

	public static List> listKeyMaps(String jsonString) {
		List> list = new ArrayList>();
		try {
			Gson gson = new Gson();
			list = gson.fromJson(jsonString,
					new TypeToken>>() {
					}.getType());
		} catch (Exception e) {
			// TODO: handle exception
		}
		return list;
	}
}
 

三、JSON解析之FastJSON

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;

public class JsonTool {

	public static  T getPerson(String jsonstring, Class cls) {
		T t = null;
		try {
			t = JSON.parseObject(jsonstring, cls);
		} catch (Exception e) {
			// TODO: handle exception
		}
		return t;
	}

	public static  List getPersonList(String jsonstring, Class cls) {
		List list = new ArrayList();
		try {
			list = JSON.parseArray(jsonstring, cls);
		} catch (Exception e) {
			// TODO: handle exception
		}
		return list;
	}

	public static  List> getPersonListMap1(
			String jsonstring) {
		List> list = new ArrayList>();
		try {
			list = JSON.parseObject(jsonstring,
					new TypeReference>>() {
					}.getType());

		} catch (Exception e) {
			// TODO: handle exception
		}

		return list;
	}
}

總結：