android解析json

最近客户端需求变更，服务器发送json格式的数据解析，但是我在做javaEE的时候，发现json是可以直接得到List ，class对象这些的，而在本身的android里面，省略了这些，所以这些需要自己来写，个人觉得，如果封装一个工具类就好了，如果使用反射机制就可以封装出来一个，但是实体类的字段就必须是public的！

下面是这个工具类的代码：

[java] view
plaincopy

<p>package com.zhangkeinfo.json.util;</p><p>

import java.lang.reflect.Field;

import java.lang.reflect.Type;

import java.util.ArrayList;

import java.util.List;</p><p>import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;</p><p>import android.util.Log;

/**

* json util class ,use in for analyzing json

* @author spring sky

* Email:vipa1888@163.com

* QQ:840950105

* 2011-12-14 15:39:51

*

*/

public class JsonUtil {

private static final String TAG = "jsonUtil";

private JSONObject jsonObject;

private JsonUtil(String json)

{

Log.e(TAG, "json="+json);

jsonObject = getJsonObject(json);

if(jsonObject==null)

{

Log.e(TAG, "jsonobject is null");

}

}

private JsonUtil() {

super();

}</p><p> public static JsonUtil newJsonUtil(String json)

{

JsonUtil util = new JsonUtil(json);

return util;

}

/**

* get json object

* @param json json data

* @return JOSNObject

*/

public JSONObject getJsonObject(String json)

{

JSONObject jsonObject = null;

try {

jsonObject = new JSONObject(json);

} catch (JSONException e) {

Log.e(TAG, "create jsonobject exception");

e.printStackTrace();

}

return jsonObject;

}

/**

* get String data

* @param json json data

* @param key param

* @return String data

* @throws JSONException

*/

public String getString(String key)

{

if(jsonObject!= null)

{

try {

return jsonObject.getString(key);

} catch (Exception e) {

e.printStackTrace();

return null;

}

}else{

return null;

}

}

/**

* get String data

* @param json json data

* @param key param

* @return int data

* @throws JSONException

*/

public int getInt(String key)

{

if(jsonObject!= null)

{

try {

return jsonObject.getInt(key);

} catch (Exception e) {

e.printStackTrace();

return -1;

}

}else{

return -1;

}

}

/**

* get Double data

* @param json json data

* @param key param

* @return double data

* @throws JSONException

*/

public double getDouble(String key)

{

if(jsonObject!= null)

{

try {

return jsonObject.getDouble(key);

} catch (Exception e) {

e.printStackTrace();

return -1;

}

}else{

return -1;

}

}

/**

* This Method use in jsonObject get current class with object

* @param jsonObject

* @param c class

* @return object

* @throws Exception

*/

public Object getObject(Class<?> c)

{

if(jsonObject!=null)

{

try {

return getObject(c.getSimpleName().toLowerCase(),c);

} catch (Exception e) {

e.printStackTrace();

return null;

}

}else{

return null;

}

}

/**

* This Method use in jsonObject get current class with object

* @param jsonObject

* @param key query key

* @param c class

* @return object

* @throws Exception

*/

public Object getObject(String key,Class<?> c)

{

if(jsonObject!=null)

{

try {

return getObject(jsonObject, key, c);

} catch (Exception e) {

e.printStackTrace();

return null;

}

}else{

return null;

}

}

public Object getObject(JSONObject jsonObject,Class<?> c)

{

try {

return getObject(jsonObject, c.getSimpleName().toLowerCase(), c);

} catch (Exception e) {

e.printStackTrace();

return null;

}

}

/**

* This Method use in jsonObject get current class with object

* @param jsonObject

* @param key query key

* @param c class

* @return object

* @throws InstantiationException

* @throws IllegalAccessException

* @throws Exception

*/

public Object getObject(JSONObject jsonObject, String key,Class<?> c) throws IllegalAccessException, InstantiationException

{

Log.e(TAG,"key == " + key);

Object bean =null ;

if(jsonObject!=null)

{

JSONObject jo = null;

if(key!=null)

{

try {

jo = jsonObject.getJSONObject(key);

} catch (JSONException e) {

e.printStackTrace();

jo = null;

}

}else{

jo = jsonObject;

}

if(jo!=null)

{

if(c.equals(null))

{

Log.e(TAG, "class is null");

try {

bean = jo.get(key);

} catch (JSONException e) {

e.printStackTrace();

bean = null;

}

}else{

bean = c.newInstance();

Field[] fs = c.getDeclaredFields();

for (int i = 0; i < fs.length; i++) {

Field f = fs[i];

f.setAccessible(true);

Type type = f.getGenericType();

String value;

try {

value = jo.getString(f.getName());

} catch (Exception e) {

value =null;

}

Log.e(TAG,f.getName()+"="+value);

if(type.equals(int.class))

{

f.setInt(bean,value==null?-1:Integer.valueOf(value));

}else if(type.equals(double.class)){

f.setDouble(bean,value==null?-1:Double.valueOf(value));

}else if(type.getClass().equals(java.util.List.class)){

Log.e(TAG, "this type is list");

}else{

f.set(bean,value);

}

}

}

}else{

Log.e(TAG, "in jsonobject not key ");

}

}else{

Log.e(TAG, "current param jsonobject is null");

}

return bean;

}

/**

* This method use in jsonObject get list object

* @param key list key

* @param objectKey object key

* @param c object

* @return list

* @throws Exception

*/

public List<Object> getList(String key ,Class<?> c,int total)

{

List<Object> list = null;

try {

if(jsonObject!=null)

{

list = new ArrayList<Object>();

if(total==1)

{

Object object = getObject(key, c);

list.add(object);

}else{

JSONArray jsonArray = jsonObject.getJSONArray(key);

if(!jsonArray.isNull(0))

{

for (int i = 0; i < jsonArray.length(); i++) {

JSONObject jsObject = jsonArray.getJSONObject(i);

Object object = getObject(jsObject, null, c);

if(object!=null)

{

list.add(object);

}

}

}

}

}

} catch (Exception e) {

e.printStackTrace();

list=null;

}

return list;

}

/**

* Test class field value

* @param c

* @param classObject

* @throws IllegalArgumentException

* @throws IllegalAccessException

*/

public static String getFieldValue(Class<?> c,Object classObject) throws IllegalArgumentException, IllegalAccessException

{

StringBuffer sb = new StringBuffer();

Field[] fs = c.getFields();

for (int i = 0; i < fs.length; i++) {

String s = fs[i].getName()+"="+fs[i].get(classObject);

sb.append(s).append("\n");

}

// Log.e(TAG, sb.toString());

return sb.toString();

}

}

</p>

一个测试的实体类：

wallpaper ：

[html] view
plaincopy

package com.zhangkeinfo.json.model.response;

public class Wallpaper{

public int id;

public String name;

public int rank;

public String img;

public String preview1url;

public String preview2url;

public String preview3url;

public String msg;

public int ptotal;

}

Price:

[html] view
plaincopy

package com.zhangkeinfo.json.model.response;

public class Price {

public int id;

public int price ;

public String name;

}

解析测试：

[java] view
plaincopy

package com.zhangkeinfo.json;

import java.lang.reflect.Field;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.zhangkeinfo.json.model.request.ZmxURL;

import com.zhangkeinfo.json.model.response.Price;

import com.zhangkeinfo.json.model.response.Wallpaper;

import com.zhangkeinfo.json.network.NetWorkUtil;

import com.zhangkeinfo.json.util.JsonUtil;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

public class MainActivity1 extends Activity implements OnClickListener{

private static final String TAG = "MainActivity";

Button button1,button2;

TextView text;

/**

* 测试的json数据

*/

public String json = "{\"id\":\"17\",\"res\":\"1\",\"wallpaper\":{\"id\":\"50\",\"name\":\"壁纸1\",\"rank\":\"0\",\"img\":\"img/a.png\",\"preview1url\":\"img/a.png\",\"preview2url\":\"img/a.png\",\"preview3url\":\"img/a.png\",\"msg\":\"\",\"ptotal\":\"1\"},\"price\":[{\"id\":\"1\",\"price\":\"1\",\"name\":\"点播\"},{\"id\":\"2\",\"price\":\"6\",\"name\":\"包月\"}]}";

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

button1 = (Button) this.findViewById(R.id.button1);

button1.setOnClickListener(this);

}

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.button1:

try {

StringBuffer sb = new StringBuffer();

/**

* 得到实例对象

*/

JsonUtil util1 = JsonUtil.newJsonUtil(json);

/*

* 得到list对象 第三个参数是这个list中一共有多少个对象 //ptotal就是获取订阅方式的个数

*/

List<Object> list = util1.getList("prices", Price.class,util1.get("ptotal")); for(int i =0 ;i< list.size();i++)

{

Price price = (Price) list.get(i);

sb.append(JsonUtil.getFieldValue(Price.class, price));

}

/**

* 得到对象

*/

Wallpaper wallpaper = (Wallpaper) util1.getObject( Wallpaper.class);

if(wallpaper!=null)

{

/**

* 反射得到字段的内容

*/

Field[] fs = Wallpaper.class.getFields();

for (int i = 0; i < fs.length; i++) {

String s = fs[i].getName()+"="+fs[i].get(wallpaper);

sb.append(s).append("\n");

}

}else{

sb.append("wallpaper is null");

}

text.setText(sb.toString());

} catch (Exception e) {

e.printStackTrace();

}

break;

}

}

}

上面的代码，复制测试就可以了，本人也只是对反射机制了解一个基础，更深层次的还需要深入的研究的！

（源自：http://blog.csdn.net/vipa1888/article/details/7071389）