Android中数据文件解析（Json解析）

首先说一下Json数据的最基本的特点，Json数据是一系列的键值对的集合,和XML数据来比，Json数据的体积更加小，传输效率高，易解析，不过可读性不高;

      因为这次要从服务器端得到Json数据，并且通过解析之后把解析后的数据显示在Android客户端中，首先部署服务器端代码(直接使用Jsp/Servlet):

       构造的Json数据如下:

     [{"name":"张三","address":"北京","age":20},{"name":"李四","address":"上海","age":30},{"name":"王五","address":"深圳","age":35}]

[一]服务器端(Person.java省略):

     ①:数据构造JsonService.java

public class JsonService {public static List<Person> getListPerson() {List<Person> mLists = new ArrayList<Person>();mLists.add(new Person("张三", "北京", 20));mLists.add(new Person("李四", "上海", 30));mLists.add(new Person("王五", "深圳", 35));return mLists;}

②:Servlet的代码（包括构造Json数据，没有使用Json数据转换方法）JsonServlet.java

public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/html");response.setCharacterEncoding("UTF-8");PrintWriter out = response.getWriter();List<Person> persons = JsonService.getListPerson();StringBuffer sb = new StringBuffer();sb.append('[');for (Person person : persons) {sb.append('{').append("\"name\":").append("\""+person.getName()+"\"").append(",");sb.append("\"address\":").append("\""+person.getAddress()+"\"").append(",");sb.append("\"age\":").append(person.getAge());sb.append('}').append(",");}sb.deleteCharAt(sb.length() - 1);sb.append(']');out.write(new String(sb));out.flush();out.close();}

  ③:部署到Tomact 浏览器输入http://localhost/JsonWeb/JsonServlet直接访问结果如下:

       至此服务器端代码编码完成，下面进行客户端代码编写;
  
  (二)客户端(Person类，和展示数据的布局文件因为简单省去)


      ①:获取服务器端的Json数据并且解析的工具类JsonParse.java


  必要的需要导入的包省去   

public class JsonParse {/*** 解析Json数据* * @param urlPath* @return mlists* @throws Exception*/public static List<Person> getListPerson(String urlPath) throws Exception {List<Person> mlists = new ArrayList<Person>();byte[] data = readParse(urlPath);JSONArray array = new JSONArray(new String(data));for (int i = 0; i < array.length(); i++) {JSONObject item = array.getJSONObject(i);String name = item.getString("name");String address = item.getString("address");int age = item.getInt("age");mlists.add(new Person(name, address, age));}return mlists;}/*** 从指定的url中获取字节数组* * @param urlPath* @return 字节数组* @throws Exception*/public static byte[] readParse(String urlPath) throws Exception {ByteArrayOutputStream outStream = new ByteArrayOutputStream();byte[] data = new byte[1024];int len = 0;URL url = new URL(urlPath);HttpURLConnection conn = (HttpURLConnection) url.openConnection();InputStream inStream = conn.getInputStream();while ((len = inStream.read(data)) != -1) {outStream.write(data, 0, len);}inStream.close();return outStream.toByteArray();}}

②:主Activity类

public class MainActivity extends Activity {private Button mButton;private ListView mListView;//使用IP不能使用localhost或者127.0.0.1，因为android模拟器默认绑定这个IP，这里应该访问局域网IPprivate static final String urlPath = "http://10.16.31.207/JsonWeb/JsonServlet";private static final String TAG = "MainActivity";private List<Person> persons;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);mButton = (Button) findViewById(R.id.button1);mListView = (ListView) findViewById(R.id.listView1);mButton.setOnClickListener(new MyOnClickListener());}private class MyOnClickListener implements OnClickListener {@Overridepublic void onClick(View v) {try {// 得到Json解析成功之后数据persons = JsonParse.getListPerson(urlPath);List<HashMap<String, Object>> data = new ArrayList<HashMap<String, Object>>();for (int i = 0; i < persons.size(); i++) {HashMap<String, Object> map = new HashMap<String, Object>();map.put("name", persons.get(i).getName());map.put("address", persons.get(i).getAddress());map.put("age", persons.get(i).getAge());data.add(map);}//初始化适配器，并且绑定数据SimpleAdapter _Adapter = new SimpleAdapter(MainActivity.this,data, R.layout.listview_item, new String[] { "name","address", "age" }, new int[] { R.id.textView1,R.id.textView2, R.id.textView3 });mListView.setAdapter(_Adapter);} catch (Exception e) {Toast.makeText(MainActivity.this, "解析失败", 2000).show();Log.i(TAG, e.toString());}}}