Android JSON、GSON、FastJson的封装与解析

声明：
1、本帖只提供代码，不深入讲解原理。如果读者想要深入了解，那就不要在这个帖子上浪费时间了
2、客户端用的是Google官方的Volley访问服务器，具体了解Volley请戳 这里
3、本帖三种数据解析的DEMO都用到了下面这个Person类，贴出来：

 public class Person {
     private String name;
     private int age;
     private String address;

     public Person() {

     }

     public Person(String name, int age, String address) {
         super();
         this.name = name;
         this.age = age;
         this.address = address;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public String getAddress() {
         return address;
     }

     public void setAddress(String address) {
         this.address = address;
     }
 }

Person实体类

一、JSON的封装和解析

服务端 的代码如下：

在MyEclipse中新建一个Web Project，把JSON操作所需要的JAR包（点击这里下载）导入到项目中。

 public class JsonTools {
     // 封装JSON字符串
     public static String createJsonString(String key, Object value) {
         JSONObject jsonObject = new JSONObject();
         jsonObject.put(key, value);
         return jsonObject.toString();
     }
 }

封装JSON字符串的工具类

 public class JsonService {
     public Person getPerson() {
         return new Person("张三", 20, "北京");
     }

     public List<Person> getPersons() {
         List<Person> list = new ArrayList<Person>();
         list.add(new Person("张三", 20, "北京"));
         list.add(new Person("李四", 22, "上海"));
         list.add(new Person("王五", 21, "天津"));
         return list;
     }

     public List<String> getStrings() {
         List<String> list = new ArrayList<String>();
         list.add("星期一");
         list.add("星期二");
         list.add("星期三");
         list.add("星期四");
         list.add("星期五");
         return list;
     }

     public List<Map<String, String>> getMaps() {
         List<Map<String, String>> list = new ArrayList<Map<String, String>>();
         Map<String, String> hashMap = new HashMap<String, String>();
         hashMap.put("name", "Jack");
         hashMap.put("phone", "123456789");
         hashMap.put("address", "Canada");
         list.add(hashMap);
         hashMap = new HashMap<String, String>();
         hashMap.put("name", "Rose");
         hashMap.put("phone", "123789456");
         hashMap.put("address", "America");
         list.add(hashMap);
         hashMap = new HashMap<String, String>();
         hashMap.put("name", "Tom");
         hashMap.put("phone", "789456123");
         hashMap.put("address", "China");
         list.add(hashMap);
         return list;
     }
 }

生成几种简单类型的数据的类

 public class JsonServlet extends HttpServlet {
     private JsonService service;

     public JsonServlet() {
         super();
     }

     public void destroy() {
         super.destroy();
     }

     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         response.setContentType("text/html;charset=UTF-8");
         request.setCharacterEncoding("UTF-8");
         response.setCharacterEncoding("UTF-8");
         PrintWriter out = response.getWriter();

         String key = request.getParameter("key");
         if (key.equals("person")) {
             Person person = service.getPerson();
             out.println(JsonTools.createJsonString("person", person));
         } else if (key.equals("persons")) {
             List<Person> persons = service.getPersons();
             out.println(JsonTools.createJsonString("persons", persons));
         } else if (key.equals("strings")) {
             List<String> strings = service.getStrings();
             out.println(JsonTools.createJsonString("strings", strings));
         } else if (key.equals("maps")) {
             List<Map<String, String>> maps = service.getMaps();
             out.println(JsonTools.createJsonString("maps", maps));
         }
     }

     public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         doGet(request, response);
     }

     public void init() throws ServletException {
         service = new JsonService();
     }
 }

测试用的Servlet类

对于输入的URL不同，结果如下：

客户端 的代码如下：

在解析JSON时，客户端不需要导入任何包。

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="#ffffffff" >

     <TextView
         android:id="@+id/person_result"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:textColor="#ff000000"
         android:textSize="15.0sp" />

     <TextView
         android:id="@+id/persons_result"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@id/person_result"
         android:layout_marginTop="10.0dip"
         android:textColor="#ff000000"
         android:textSize="15.0sp" />

     <TextView
         android:id="@+id/strings_result"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@id/persons_result"
         android:layout_marginTop="10.0dip"
         android:textColor="#ff000000"
         android:textSize="15.0sp" />

     <TextView
         android:id="@+id/maps_result"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_below="@id/strings_result"
         android:layout_marginTop="10.0dip"
         android:textColor="#ff000000"
         android:textSize="15.0sp" />

 </RelativeLayout>

MainActivity类的布局代码

 public class JsonTools {
     public void getResult(TextView view, JSONObject jsonObject) {
         switch (view.getId()) {
         case R.id.person_result:
             view.setText(getPerson(jsonObject));
             break;
         case R.id.persons_result:
             view.setText(getPersons(jsonObject));
             break;
         case R.id.strings_result:
             view.setText(getStrings(jsonObject));
             break;
         case R.id.maps_result:
             view.setText(getMaps(jsonObject));
             break;
         }
     }

     private String getPerson(JSONObject jsonObject) {
         String result = "-->从服务器获取Person数据\n";
         try {
             JSONObject personObject = jsonObject.getJSONObject("person");
             result += "姓名：" + personObject.getString("name") + "\n";
             result += "年龄：" + personObject.getString("age") + "\n";
             result += "地址：" + personObject.getString("address");
         } catch (JSONException e) {
             e.printStackTrace();
         }
         return result;
     }

     private String getPersons(JSONObject jsonObject) {
         String result = "-->从服务器获取List<Person>数据\n";
         try {
             JSONArray jsonArray = jsonObject.getJSONArray("persons");
             for (int i = 0; i < jsonArray.length(); i++) {
                 result += "-第" + (i + 1) + "组数据：\n";
                 JSONObject subObject = jsonArray.getJSONObject(i);
                 result += "姓名：" + subObject.getString("name") + "\n";
                 result += "年龄：" + subObject.getString("age") + "\n";
                 result += "地址：" + subObject.getString("address");
                 if (i != jsonArray.length() - 1) {
                     result += "\n";
                 }
             }
         } catch (JSONException e) {
             e.printStackTrace();
         }
         return result;
     }

     private String getStrings(JSONObject jsonObject) {
         String result = "-->从服务器获取List<String>数据\n";
         try {
             JSONArray jsonArray = jsonObject.getJSONArray("strings");
             for (int i = 0; i < jsonArray.length(); i++) {
                 result += jsonArray.getString(i);
                 if (i != jsonArray.length() - 1) {
                     result += " -> ";
                 }
             }
         } catch (JSONException e) {
             e.printStackTrace();
         }
         return result;
     }

     private String getMaps(JSONObject jsonObject) {
         String result = "-->从服务器获取List<HashMap<String,String>>数据\n";
         try {
             JSONArray jsonArray = jsonObject.getJSONArray("maps");
             for (int i = 0; i < jsonArray.length(); i++) {
                 result += "-第" + (i + 1) + "组数据：\n";
                 JSONObject subObject = jsonArray.getJSONObject(i);
                 result += "姓名：" + subObject.getString("name") + "\n";
                 result += "电话：" + subObject.getString("phone") + "\n";
                 result += "地址：" + subObject.getString("address");
                 if (i != jsonArray.length() - 1) {
                     result += "\n";
                 }
             }
         } catch (JSONException e) {
             e.printStackTrace();
         }
         return result;
     }
 }

处理JSON的工具类

 public class MainActivity extends Activity {
     private final String url = "http://192.168.1.102:8080/JsonServer/JsonServlet";
     private TextView person_result, persons_result, strings_result, maps_result;
     private JsonTools jsonTools;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         person_result = (TextView) findViewById(R.id.person_result);
         persons_result = (TextView) findViewById(R.id.persons_result);
         strings_result = (TextView) findViewById(R.id.strings_result);
         maps_result = (TextView) findViewById(R.id.maps_result);
         jsonTools = new JsonTools();

         getResponseToView(url + "?key=person", "json_person", person_result);
         getResponseToView(url + "?key=persons", "json_persons", persons_result);
         getResponseToView(url + "?key=strings", "json_strings", strings_result);
         getResponseToView(url + "?key=maps", "json_maps", maps_result);
     }

     private void getResponseToView(String url, String tag, final TextView view) {
         StringRequest request = new StringRequest(Method.GET, url, new Listener<String>() {
             @Override
             public void onResponse(String response) {
                 try {
                     JSONObject resultObject = new JSONObject(response);
                     jsonTools.getResult(view, resultObject);
                 } catch (JSONException e) {
                     e.printStackTrace();
                 }
             }
         }, new Response.ErrorListener() {
             @Override
             public void onErrorResponse(VolleyError arg0) {
                 view.setText(arg0.toString());
             }
         });
         request.setTag(tag);
         MyApplication.getRequestQueue().add(request);
     }

     @Override
     protected void onStop() {
         super.onStop();
         MyApplication.getRequestQueue().cancelAll("JsonRequest");
     }
 }

主界面MainActivity的代码

运行结果如下图所示：

二、GSON的封装和解析

服务端 的代码如下（生成数据的类GsonService和JsonService类相同，这里就不再贴了）：

在MyEclipse中新建一个Web Project，将GSON操作所需要的JAR包（点击这里下载）导入到项目中。

 public class GsonTools {
     // 生成GSON字符串
     public static String createGsonString(Object value) {
         Gson gson = new Gson();
         String gsonString = gson.toJson(value);
         return gsonString;
     }
 }

生成GSON字符串的类

 public class GsonServlet extends HttpServlet {
     private GsonService service;

     public GsonServlet() {
         super();
     }

     public void destroy() {
         super.destroy();
     }

     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         response.setContentType("text/html;charset=UTF-8");
         request.setCharacterEncoding("UTF-8");
         response.setCharacterEncoding("UTF-8");
         PrintWriter out = response.getWriter();

         String key = request.getParameter("key");
         if (key.equals("person")) {
             Person person = service.getPerson();
             out.println(GsonTools.createGsonString(person));
         } else if (key.equals("persons")) {
             List<Person> persons = service.getPersons();
             out.println(GsonTools.createGsonString(persons));
         } else if (key.equals("strings")) {
             List<String> strings = service.getStrings();
             out.println(GsonTools.createGsonString(strings));
         } else if (key.equals("maps")) {
             List<Map<String, String>> maps = service.getMaps();
             out.println(GsonTools.createGsonString(maps));
         }
     }

     public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         doGet(request, response);
     }

     public void init() throws ServletException {
         service = new GsonService();
     }
 }

测试用的Servlet类

对于输入的URL不同，结果如下：

客户端 的代码如下（MainActivity类的布局代码和上面的一样）：

在解析GSON时，客户端需要导入和服务端相同的包。

 public class GsonTools {
     public static <T> T getPerson(String jsonString, Class<T> cls) {
         T t = null;
         try {
             Gson gson = new Gson();
             t = gson.fromJson(jsonString, cls);
         } catch (Exception e) {
             e.printStackTrace();
         }
         return t;
     }

     public static <T> List<T> getPersons(String jsonString, Class<T[]> cls) {
         List<T> list = null;
         try {
             Gson gson = new Gson();
             list = Arrays.asList(gson.fromJson(jsonString, cls));
         } catch (Exception e) {
             e.printStackTrace();
         }
         return list;
     }

     public static List<String> getStrings(String jsonString) {
         List<String> list = null;
         try {
             Gson gson = new Gson();
             list = gson.fromJson(jsonString, new TypeToken<List<String>>() {
             }.getType());
         } catch (Exception e) {
             e.printStackTrace();
         }
         return list;
     }

     public static <T> List<HashMap<String, T>> getMaps(String jsonString,Class<T> cls) {
         List<HashMap<String, T>> list = new ArrayList<HashMap<String, T>>();
         try {
             Gson gson = new Gson();
             list = gson.fromJson(jsonString, new TypeToken<List<HashMap<String, T>>>() {
             }.getType());
         } catch (Exception e) {
             e.printStackTrace();
         }
         return list;
     }
 }

处理受到的数据的工具类

 public class MainActivity extends Activity {
     private final String url = "http://192.168.1.102:8080/GsonServer/GsonServlet";
     private TextView person_result, persons_result, strings_result, maps_result;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         person_result = (TextView) findViewById(R.id.person_result);
         persons_result = (TextView) findViewById(R.id.persons_result);
         strings_result = (TextView) findViewById(R.id.strings_result);
         maps_result = (TextView) findViewById(R.id.maps_result);

         getResultToView(url + "?key=person", "GsonPerson", person_result);
         getResultToView(url + "?key=persons", "GsonPersons", persons_result);
         getResultToView(url + "?key=strings", "GsonStrings", strings_result);
         getResultToView(url + "?key=maps", "GsonMaps", maps_result);
     }

     private void getResultToView(String url, String tag, final TextView view) {
         StringRequest request = new StringRequest(Method.GET, url, new Listener<String>() {
             @Override
             public void onResponse(String response) {
                 manageResponse(response, view);
             }
         }, new ErrorListener() {
             @Override
             public void onErrorResponse(VolleyError arg0) {
                 view.setText(arg0.toString());
             }
         });
         request.setTag(tag);
         MyApplication.getRequestQueue().add(request);
     }

     // 将GsonTools类返回的处理好的JAVA对象进行排版并输出到对应TextView中
     private void manageResponse(String response, TextView view) {
         switch (view.getId()) {
         case R.id.person_result:
             addTextToView(view, "-->从服务器获取Person数据\n");
             Person person = GsonTools.getPerson(response, Person.class);
             addTextToView(view, "姓名：" + person.getName() + "\n年龄：" + person.getAge() + "\n地址：" + person.getAddress());
             break;
         case R.id.persons_result:
             addTextToView(view, "-->从服务器获取List<Person>数据\n");
             List<Person> persons = GsonTools.getPersons(response, Person[].class);
             for (int i = 0; i < persons.size(); i++) {
                 Person p = persons.get(i);
                 addTextToView(view, "-第" + (i + 1) + "条数据\n");
                 addTextToView(view, "姓名：" + p.getName() + "\n年龄：" + p.getAge() + "\n地址：" + p.getAddress());
                 if (i != persons.size() - 1) {
                     addTextToView(view, "\n");
                 }
             }
             break;
         case R.id.strings_result:
             addTextToView(view, "-->从服务器获取List<String>数据\n");
             List<String> strings = GsonTools.getStrings(response);
             for (int i = 0; i < strings.size(); i++) {
                 addTextToView(view, strings.get(i));
                 if (i != strings.size() - 1) {
                     addTextToView(view, " -> ");
                 }
             }
             break;
         case R.id.maps_result:
             addTextToView(view, "-->从服务器获取List<HashMap<String,Object>>数据\n");
             List<HashMap<String, String>> maps = GsonTools.getMaps(response, String.class);
             for (int i = 0; i < maps.size(); i++) {
                 addTextToView(view, "-第" + (i + 1) + "条数据：\n");
                 addTextToView(view, "姓名：" + maps.get(i).get("name").toString() + "\n");
                 addTextToView(view, "电话：" + maps.get(i).get("phone").toString() + "\n");
                 addTextToView(view, "地址：" + maps.get(i).get("address").toString());
                 if (i != maps.size() - 1) {
                     addTextToView(view, "\n");
                 }
             }
             break;
         }
     }

     // 向指定TextView中添加文本
     private void addTextToView(TextView view, String text) {
         String currentText = view.getText().toString();
         currentText += text;
         view.setText(currentText);
     }

     @Override
     protected void onStop() {
         super.onStop();
         MyApplication.getRequestQueue().cancelAll("GsonPerson");
         MyApplication.getRequestQueue().cancelAll("GsonPersons");
         MyApplication.getRequestQueue().cancelAll("GsonStrings");
         MyApplication.getRequestQueue().cancelAll("GsonMaps");    }
 }

主界面MainActivity中的代码

运行结果如下图：

三、FastJSON的封装和解析

服务端 的代码和使用GSON解析时的服务端代码相同（不需要改变任何东西，包括JAR包）。

客户端 的代码如下：

在解析FastJSON时，客户端需要导入解析FastJSON所需要的JAR包（点击这里下载）。

 public class FastJsonTools {
     public static <T> T getPerson(String jsonString, Class<T> cls) {
         T t = null;
         try {
             t = JSON.parseObject(jsonString, cls);
         } catch (Exception e) {
             e.printStackTrace();
         }
         return t;
     }

     // 解析List<Person>数据和List<String>数据都使用这个方法
     public static <T> List<T> getPersons(String jsonString, Class<T> cls) {
         List<T> list = null;
         try {
             list = JSON.parseArray(jsonString, cls);
         } catch (Exception e) {
             e.printStackTrace();
         }
         return list;
     }

     public static List<HashMap<String, Object>> getMaps(String jsonString) {
         List<HashMap<String, Object>> maps = new ArrayList<HashMap<String, Object>>();
         try {
             maps = JSON.parseObject(jsonString, new TypeReference<List<HashMap<String, Object>>>() {
             });
         } catch (Exception e) {
             e.printStackTrace();
         }
         return maps;
     }
 }

处理收到的数据的工具类

 public class MainActivity extends Activity {
     private final String url = "http://192.168.1.102:8080/GsonServer/GsonServlet";
     private TextView person_result, persons_result, strings_result, maps_result;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         person_result = (TextView) findViewById(R.id.person_result);
         persons_result = (TextView) findViewById(R.id.persons_result);
         strings_result = (TextView) findViewById(R.id.strings_result);
         maps_result = (TextView) findViewById(R.id.maps_result);

         getResultToView(url + "?key=person", "FastJsonPerson", person_result);
         getResultToView(url + "?key=persons", "FastJsonPersons", persons_result);
         getResultToView(url + "?key=strings", "FastJsonStrings", strings_result);
         getResultToView(url + "?key=maps", "FastJsonMaps", maps_result);
     }

     private void getResultToView(String url, String tag, final TextView view) {
         StringRequest request = new StringRequest(Method.GET, url, new Listener<String>() {
             @Override
             public void onResponse(String response) {
                 manageResponse(view, response);
             }
         }, new Response.ErrorListener() {
             @Override
             public void onErrorResponse(VolleyError arg0) {
                 addTextToView(view, arg0.toString());
             }
         });
         request.setTag(tag);
         MyApplication.getRequestQueue().add(request);
     }

     private void addTextToView(TextView view, String text) {
         String currentText = view.getText().toString();
         currentText += text;
         view.setText(currentText);
     }

     private void manageResponse(TextView view, String response) {
         switch (view.getId()) {
         case R.id.person_result:
             addTextToView(view, "-->从服务端获取Person数据\n");
             Person person = FastJsonTools.getPerson(response, Person.class);
             addTextToView(view,
                     "姓名：" + person.getName() + "\n年龄：" + person.getAddress() + "\n地址：" + person.getAddress());
             break;
         case R.id.persons_result:
             addTextToView(view, "-->从服务器获取List<Person>数据\n");
             List<Person> persons = FastJsonTools.getPersons(response, Person.class);
             for (int i = 0; i < persons.size(); i++) {
                 Person p = persons.get(i);
                 addTextToView(view, "-第" + (i + 1) + "条数据\n");
                 addTextToView(view, "姓名：" + p.getName() + "\n年龄：" + p.getAge() + "\n地址：" + p.getAddress());
                 if (i != persons.size() - 1) {
                     addTextToView(view, "\n");
                 }
             }
             break;
         case R.id.strings_result:
             addTextToView(view, "-->从服务器获取List<String>数据\n");
             List<String> strings = FastJsonTools.getPersons(response, String.class);
             for (int i = 0; i < strings.size(); i++) {
                 addTextToView(view, strings.get(i));
                 if (i != strings.size() - 1) {
                     addTextToView(view, " -> ");
                 }
             }
             break;
         case R.id.maps_result:
             addTextToView(view, "-->从服务器获取List<HashMap<String,Object>>数据\n");
             List<HashMap<String, Object>> maps = FastJsonTools.getMaps(response);
             for (int i = 0; i < maps.size(); i++) {
                 addTextToView(view, "-第" + (i + 1) + "条数据：\n");
                 addTextToView(view, "姓名：" + maps.get(i).get("name").toString() + "\n");
                 addTextToView(view, "电话：" + maps.get(i).get("phone").toString() + "\n");
                 addTextToView(view, "地址：" + maps.get(i).get("address").toString());
                 if (i != maps.size() - 1) {
                     addTextToView(view, "\n");
                 }
             }
             break;
         }
     }

     @Override
     protected void onStop() {
         super.onStop();
         MyApplication.getRequestQueue().cancelAll("FastJsonPerson");
         MyApplication.getRequestQueue().cancelAll("FastJsonPersons");
         MyApplication.getRequestQueue().cancelAll("FastJsonStrings");
         MyApplication.getRequestQueue().cancelAll("FastJsonMaps");
     }
 }

主界面MainActiivty中的代码

运行结果如下图：