Android中数据文件解析（Json解析【从服务器端获取数据并且解析，显示在客户端上面】）

      前面学习过了使用SAX解析XML数据(点击进入:SAX解析XML数据),今天学习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 getListPerson() {
		List mLists = new ArrayList();
		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 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 getListPerson(String urlPath) throws Exception {
		List mlists = new ArrayList();
		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IP
	private static final String urlPath = "http://10.16.31.207/JsonWeb/JsonServlet";
	private static final String TAG = "MainActivity";
	private List persons;
	@Override
	public 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 {
		@Override
		public void onClick(View v) {
			try {
				// 得到Json解析成功之后数据
				persons = JsonParse.getListPerson(urlPath);
				List> data = new ArrayList>();
				for (int i = 0; i < persons.size(); i++) {
					HashMap map = new HashMap();
					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());

			}
		}
	}

         

   至此服务器端和客户端编码介绍，运行android应用结果截图:

      源代码下载链接:http://download.csdn.net/detail/jiangqq781931404/4087194