Android利用Json来进行网络数据传输
最近做一项目，有很多地方得用到网络数据传输与解析，这里采用的是Json方式，它与传统的XML解析方式比起来，有自己的一些优点，首先，它是比XML更轻量级，再一个，写一个XML文件是个烦人的事儿，而Json则相对轻松些。
Android平台有Jsong相关的类来进行Json数据解析，悲剧的是，它们是Android SDK3.0以后才能用的。不过在谷歌网站：http://code.google.com/p/google-gson/里有一个名为Gson的类库，可以用它来解析Json数据，并且，Adroid 3.0平台里其实也就是把这一部分直接整合进Android里了。我们要解析Json数据，直接去网站上下载个jar包，导入到工程里，就可以解析Json数据了。
下面有个例子,很清晰的解释了这种工作方式：
先看看两个我自己封装的类：
HttpUtils.java:
public class HttpUtils { //从服务器端下载到Json数据，也就是个字符串
public static String getData(String url) throws Exception {
StringBuilder sb = new StringBuilder();
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
if (httpEntity != null) {
InputStream instream = httpEntity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(
instream));
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
return sb.toString();
}
return null;
}
JsonUtils.java:
public class JsonUtils {
public static List<Student> parseStudentFromJson(String data) {
Type listType = new TypeToken<LinkedList<Student>>() {
}.getType();
Gson gson = new Gson();
LinkedList<Student> list = gson.fromJson(data, listType);
return list;
}
}
里面的Student是一个JavaBean对象：
public class Student {
private String name;
private int age;
private String id;
public Student() {
super();
}
public Student(String name, int age, String id) {
super();
this.name = name;
this.age = age;
this.id = id;
}
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 getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}
public class MainActivity extends Activity {
private TextView textView;
private List<Student> list;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView = (TextView) findViewById(R.id.textView);
String data = null;
try {
data = HttpUtils
.getData("http://10.16.12.165:8080/JsonTest/JsonTestServlet");
} catch (Exception e) {
e.printStackTrace();
}
String result = "";
list = JsonUtils.parseStudentFromJson(data);
for (Student s : list) {
result += "name: " + s.getName() + " " + "age: " + s.getAge()
+ " " + "id: " + s.getId() + "\n";
}
textView.setText(result);
}
}
这样就可以获取网络数据并加以解析利用了，运行结果如下：