Android系列---JSON数据解析

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

    public Person()
    {
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

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

    public String getAddress()
    {
        return address;
    }

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

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

    @Override
    public String toString()
    {
        return "Person [id=" + id + ", name=" + name + ", address=" + address
                + "]";
    }

}

public class JsonTools
{
    /**
     * 得到一个json类型的字符串对象
     * @param key
     * @param value
     * @return
     */
    public static String getJsonString(String key, Object value)
    {
        JSONObject jsonObject = new JSONObject();
        //put和element都是往JSONObject对象中放入 key/value 对
//        jsonObject.put(key, value);
        jsonObject.element(key, value);
        return jsonObject.toString();
    }
    
    /**
     * 得到一个json对象
     * @param key
     * @param value
     * @return
     */
    public static JSONObject getJsonObject(String key, Object value)
    {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put(key, value);
        return jsonObject;
    }
    
}

　　　　 Person person = new Person(1, "xiaoluo", "广州");
        //    将Person对象转换成一个json类型的字符串对象
        String personString = JsonTools.getJsonString("person", person);
        System.out.println(personString.toString());

{"person":{"address":"广州","id":1,"name":"xiaoluo"}}

　　　　 JSONObject jsonObject = JsonTools.getJsonObject("person", person);
        //    通过JSONObject的toBean方法可以将json对象转换成一个javabean
        JSONObject personObject = jsonObject.getJSONObject("person");
        Person person2 = (Person) JSONObject.toBean(personObject, Person.class);
        System.out.println(person2);

Person [id=1, name=xiaoluo, address=广州]

　　@Test
    public void testPersonsJson()
    {
        List<Person> persons = new ArrayList<Person>();
        Person person = new Person(1, "xiaoluo", "广州");
        Person person2 = new Person(2, "android", "上海");
        persons.add(person);
        persons.add(person2);
        String personsString = JsonTools.getJsonString("persons", persons);
        System.out.println(personsString);
        
        JSONObject jsonObject = JsonTools.getJsonObject("persons", persons);
        //    List<Person>相当于一个JSONArray对象
        JSONArray personsArray = (JSONArray)jsonObject.getJSONArray("persons");
        List<Person> persons2 = (List<Person>) personsArray.toCollection(personsArray, Person.class);
        System.out.println(persons2);
    }

{"persons":[{"address":"广州","id":1,"name":"xiaoluo"},{"address":"上海","id":2,"name":"android"}]}
[Person [id=1, name=xiaoluo, address=广州], Person [id=2, name=android, address=上海]]

　　 @Test
    public void testMapJson()
    {
        List<Map<String, String>> list = new ArrayList<Map<String, String>>();
        Map<String, String> map1 = new HashMap<String, String>();
        map1.put("id", "001");
        map1.put("name", "xiaoluo");
        map1.put("age", "20");
        Map<String, String> map2 = new HashMap<String, String>();
        map2.put("id", "002");
        map2.put("name", "android");
        map2.put("age", "33");
        list.add(map1);
        list.add(map2);
        String listString = JsonTools.getJsonString("list", list);
        System.out.println(listString);
        
        JSONObject jsonObject = JsonTools.getJsonObject("list", list);
        JSONArray listArray = jsonObject.getJSONArray("list");
        List<Map<String, String>> list2 = (List<Map<String, String>>) listArray.toCollection(listArray, Map.class);
        System.out.println(list2);
    }

{"list":[{"id":"001","age":"20","name":"xiaoluo"},{"id":"002","age":"33","name":"android"}]}
[{id=001, name=xiaoluo, age=20}, {id=002, name=android, age=33}]

public class JsonService
{
    public Person getPerson()
    {
        Person person = new Person(1, "xiaoluo", "广州");
        return person;
    }
    
    public List<Person> getPersons()
    {
        List<Person> persons = new ArrayList<Person>();
        Person person = new Person(1, "xiaoluo", "广州");
        Person person2 = new Person(2, "android", "上海");
        persons.add(person);
        persons.add(person2);
        return persons;
    }
    
    public List<String> getString()
    {
        List<String> list = new ArrayList<String>();
        list.add("广州");
        list.add("上海");
        list.add("北京");
        return list;
    }
    
    public List<Map<String, String>> getMapList()
    {
        List<Map<String, String>> list = new ArrayList<Map<String, String>>();
        Map<String, String> map1 = new HashMap<String, String>();
        map1.put("id", "001");
        map1.put("name", "xiaoluo");
        map1.put("age", "20");
        Map<String, String> map2 = new HashMap<String, String>();
        map2.put("id", "002");
        map2.put("name", "android");
        map2.put("age", "33");
        list.add(map1);
        list.add(map2);
        return list;
    }
}

public static void main(String[] args)
    {
        Gson gson = new Gson();
        JsonService jsonService = new JsonService();
        Person person = jsonService.getPerson();
        System.out.println("person: " + gson.toJson(person));
        //    对于Object类型，使用 fromJson(String, Class)方法来将Json对象转换成Java对象
        Person person2 = gson.fromJson(gson.toJson(person), Person.class);
        System.out.println(person2);
        System.out.println("------------------------------------------------");
        
        List<Person> persons = jsonService.getPersons();
        System.out.println("persons: " + gson.toJson(persons));
        /*
         * 对于泛型对象，使用fromJson(String, Type)方法来将Json对象转换成对应的泛型对象
         * new TypeToken<>(){}.getType()方法
         */
        List<Person> persons2 = gson.fromJson(gson.toJson(persons), new TypeToken<List<Person>>(){}.getType());
        System.out.println(persons2);
        System.out.println("------------------------------------------------");
        
        List<String> list = jsonService.getString();
        System.out.println("String---->" + gson.toJson(list));
        List<String> list2 = gson.fromJson(gson.toJson(list), new TypeToken<List<String>>(){}.getType());
        System.out.println("list2---->" + list2);
        System.out.println("------------------------------------------------");
        
        List<Map<String, String>> listMap = jsonService.getMapList();
        System.out.println("Map---->" + gson.toJson(listMap));
        List<Map<String, String>> listMap2 = gson.fromJson(gson.toJson(listMap), new TypeToken<List<Map<String, String>>>(){}.getType());
        System.out.println("listMap2---->" + listMap2);
        System.out.println("------------------------------------------------");
    }

person: {"id":1,"name":"xiaoluo","address":"广州"}
Person [id=1, name=xiaoluo, address=广州]
------------------------------------------------
persons: [{"id":1,"name":"xiaoluo","address":"广州"},{"id":2,"name":"android","address":"上海"}]
[Person [id=1, name=xiaoluo, address=广州], Person [id=2, name=android, address=上海]]
------------------------------------------------
String---->["广州","上海","北京"]
list2---->[广州, 上海, 北京]
------------------------------------------------
Map---->[{"id":"001","age":"20","name":"xiaoluo"},{"id":"002","age":"33","name":"android"}]
listMap2---->[{id=001, age=20, name=xiaoluo}, {id=002, age=33, name=android}]
------------------------------------------------

@WebServlet("/CityServlet")
public class CityServlet extends HttpServlet
{
    private static final long serialVersionUID = 1L;

    public CityServlet()
    {
        super();
    }

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

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        PrintWriter writer = response.getWriter();
        
        String type = request.getParameter("type");
        if("json".equals(type))
        {
            List<String> cities = new ArrayList<String>();
            cities.add("广州");
            cities.add("上海");
            cities.add("北京");
            cities.add("湖南");
            Map<String, List<String>> map = new HashMap<String, List<String>>();
            map.put("cities", cities);
            String citiesString = JSON.toJSONString(map);
            writer.println(citiesString);
        }
        
        writer.flush();
        writer.close();
    }

}

<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" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="64dp"
        android:layout_marginTop="64dp"
        android:textSize="20sp"
        android:text="城市" />
    
    <Spinner 
        android:id="@+id/spinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@id/textView1"
        android:layout_toRightOf="@id/textView1"/>

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/spinner"
        android:layout_marginLeft="22dp"
        android:layout_marginTop="130dp"
        android:text="加载数据" />

</RelativeLayout>

public class JsonUtils
{
    /**
     * @param citiesString    从服务器端得到的JSON字符串数据
     * @return    解析JSON字符串数据，放入List当中
     */
    public static List<String> parseCities(String citiesString)
    {
        List<String> cities = new ArrayList<String>();
        
        try
        {
            JSONObject jsonObject = new JSONObject(citiesString);
            JSONArray jsonArray = jsonObject.getJSONArray("cities");
            for(int i = 0; i < jsonArray.length(); i++)
            {
                cities.add(jsonArray.getString(i));
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        
        return cities;
    }
}

public class HttpUtils
{
    /**
     * @param path    请求的服务器URL地址
     * @param encode    编码格式
     * @return    将服务器端返回的数据转换成String
     */
    public static String sendPostMessage(String path, String encode)
    {
        String result = "";
        HttpClient httpClient = new DefaultHttpClient();
        try
        {
            HttpPost httpPost = new HttpPost(path);
            HttpResponse httpResponse = httpClient.execute(httpPost);
            if(httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK)
            {
                HttpEntity httpEntity = httpResponse.getEntity();
                if(httpEntity != null)
                {
                    result = EntityUtils.toString(httpEntity, encode);
                }
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        finally
        {
            httpClient.getConnectionManager().shutdown();
        }
        
        return result;
    }
}

public class MainActivity extends Activity
{
    private Spinner spinner;
    private Button button;
    private ArrayAdapter<String> adapter;
    private ProgressDialog dialog;
    private final String CITY_PATH_JSON = "http://172.25.152.34:8080/httptest/CityServlet?type=json";
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        spinner = (Spinner)findViewById(R.id.spinner);
        button = (Button)findViewById(R.id.button);
        dialog = new ProgressDialog(MainActivity.this);
        button.setOnClickListener(new OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                dialog.setTitle("提示信息");
                dialog.setMessage("loading......");
                dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
                dialog.setCancelable(false);
                
                new MyAsyncTask().execute(CITY_PATH_JSON);
            }
        });
    }

    public class MyAsyncTask extends AsyncTask<String, Void, List<String>>
    {
        @Override
        protected void onPreExecute()
        {
            dialog.show();
        }
        @Override
        protected List<String> doInBackground(String... params)
        {
            List<String> cities = new ArrayList<String>();
            String citiesString = HttpUtils.sendPostMessage(params[0], "utf-8");
            //    解析服务器端的json数据
            cities = JsonUtils.parseCities(citiesString);return cities;
        }
        @Override
        protected void onPostExecute(List<String> result)
        {
            adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_spinner_item, result);
            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            spinner.setAdapter(adapter);
            dialog.dismiss();
        }
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

<uses-permission android:name="android.permission.INTERNET"/>