Android利用Gson解析嵌套多层的Json的简单介绍
2016-07-24 17:06
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讲一个比较简单点的例子，帮助理解Gson的简单的使用方法：
比如我们要解析一个下面这种的Json：
String json = {"a":"100","b":[{"b1":"b_value1","b2":"b_value2"},{"b1":"b_value1","b2":"b_value2"}]，"c":{"c1":"c_value1","c2":"c_value2"}}
首先我们需要定义一个序列化的Bean，这里采用内部类的形式，看起来会比较清晰一些：
public class JsonBean {
public String a;
public List<B> b;
public C c;
public static class B {
public String b1;
public String b2;
}
public static class C {
public String c1;
public String c2;
}
}
很多时候大家都是不知道这个Bean是该怎么定义，这里面需要注意几点：
1、内部嵌套的类必须是static的，要不然解析会出错；
2、类里面的属性名必须跟Json字段里面的Key是一模一样的；
3、内部嵌套的用[]括起来的部分是一个List，所以定义为 public List<B> b，而只用{}嵌套的就定义为 public C c，
具体的大家对照Json字符串看看就明白了，不明白的我们可以互相交流，本人也是开发新手！
Gson gson = new Gson();
java.lang.reflect.Type type = new TypeToken<JsonBean>() {}.getType();//通过TypeToken获取泛型参数的类型
JsonBean jsonBean = gson.fromJson(json, type);
然后想拿数据就很简单了，直接在jsonBean里面取就可以了！
如果需要解析的Json嵌套了很多层，同样可以可以定义一个嵌套很多层内部类的Bean，需要细心的对照Json字段来定义。
下面我将以一个具体的列子来说明通过Gson方式解析复杂的json数据
1.将要解析的数据如下面的格式
{
"error": 0,
"status": "success",
"date": "2014-05-10",
"results": [
{
"currentCity": "南京",
"weather_data": [
{
"date": "周六(今天, 实时：19℃)",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/dayu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/dayu.png",
"weather": "大雨",
"wind": "东南风5-6级",
"temperature": "18℃"
},
{
"date": "周日",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/zhenyu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",
"weather": "阵雨转多云",
"wind": "西北风4-5级",
"temperature": "21 ~ 14℃"
}
]
}
]
}
2.必须定义如下一些的javaBean数据
Status.java
[java] view
plain copy
public class Status
{
private String error;
private String status;
private String date;
private List<Results> results;
public String getError()
{
return error;
}
public void setError(String error)
{
this.error = error;
}
public String getStatus()
{
return status;
}
public void setStatus(String status)
{
this.status = status;
}
public String getDate()
{
return date;
}
public void setDate(String date)
{
this.date = date;
}
public List<Results> getResults()
{
return results;
}
public void setResults(List<Results> results)
{
this.results = results;
}
@Override
public String toString()
{
return "Status [error=" + error + ", status=" + status
+ ", date=" + date + ", results=" + results + "]";
}
</span>
Results.java
public class Results
{
private String currentCity;
private List<Weather> weather_data;
public String getCurrentCity()
{
return currentCity;
}
public void setCurrentCity(String currentCity)
{
this.currentCity = currentCity;
}
public List<Weather> getWeather_data()
{
return weather_data;
}
public void setWeather_data(List<Weather> weather_data)
{
this.weather_data = weather_data;
}
@Override
public String toString()
{
return "Results [currentCity=" + currentCity + ", weather_data="
+ weather_data + "]";
}
Weather.java
public class Weather {
private String date;
private String dayPictureUrl;
private String nightPictureUrl;
private String weather;
private String wind;
private String temperature;
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getDayPictureUrl() {
return dayPictureUrl;
}
public void setDayPictureUrl(String dayPictureUrl) {
this.dayPictureUrl = dayPictureUrl;
}
public String getNightPictureUrl() {
return nightPictureUrl;
}
public void setNightPictureUrl(String nightPictureUrl) {
this.nightPictureUrl = nightPictureUrl;
}
public String getWeather() {
return weather;
}
public void setWeather(String weather) {
this.weather = weather;
}
public String getWind() {
return wind;
}
public void setWind(String wind) {
this.wind = wind;
}
public String getTemperature() {
return temperature;
}
public void setTemperature(String temperature) {
this.temperature = temperature;
}
@Override
public String toString() {
return "Weather [date=" + date + ", dayPictureUrl="
+ dayPictureUrl + ", nightPictureUrl="
+ nightPictureUrl + ", weather=" + weather
+ ", wind=" + wind + ", temperature=" + temperature
+ "]";
}
然后具体的javabean定义好了就将解析数据了，下面就是我的解析数据类
public class MainActivity extends Activity
{
private Button tojson;
RequestQueue mQueue;
StringRequest stringRequest;
Gson gson;
String str;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tojson = (Button)findViewById(R.id.tojson);
gson = new Gson();
mQueue = Volley.newRequestQueue(MainActivity.this);
//http://10.19.20.12/upgrade/test.txt是测试使用的json数据
stringRequest = new StringRequest("http://10.19.20.12/upgrade/test.txt",
new Response.Listener<String>()
{
@Override
public void onResponse(String response)
{
Log.d("TAG", response);
System.out.println("response="+response);
Status status = gson.fromJson(response, Status.class);
System.out.println("status="+status);
System.out.println("-------------------------------------");
List<Results> result = status.getResults();
System.out.println("result="+result);
}
},
new Response.ErrorListener()
{
@Override
public void onErrorResponse(VolleyError error)
{
Log.e("TAG", error.getMessage(), error);
}
});
tojson.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
mQueue.add(stringRequest);
}
});
}
}
其中上面的RequestQueue是开源网络库Volley的使用，如果你对该库的使用还不熟悉的话可以参考http://blog.csdn.net/guolin_blog/article/details/17482095，该作者对Volley库的使用讲解得非常的细致和深入
大家可以仔细的去拜读。
转载自：http://blog.csdn.net/lanxingfeifei/article/details/50736955
比如我们要解析一个下面这种的Json：
String json = {"a":"100","b":[{"b1":"b_value1","b2":"b_value2"},{"b1":"b_value1","b2":"b_value2"}]，"c":{"c1":"c_value1","c2":"c_value2"}}
首先我们需要定义一个序列化的Bean，这里采用内部类的形式，看起来会比较清晰一些：
public class JsonBean {
public String a;
public List<B> b;
public C c;
public static class B {
public String b1;
public String b2;
}
public static class C {
public String c1;
public String c2;
}
}
很多时候大家都是不知道这个Bean是该怎么定义，这里面需要注意几点：
1、内部嵌套的类必须是static的，要不然解析会出错；
2、类里面的属性名必须跟Json字段里面的Key是一模一样的；
3、内部嵌套的用[]括起来的部分是一个List，所以定义为 public List<B> b，而只用{}嵌套的就定义为 public C c，
具体的大家对照Json字符串看看就明白了，不明白的我们可以互相交流，本人也是开发新手！
Gson gson = new Gson();
java.lang.reflect.Type type = new TypeToken<JsonBean>() {}.getType();//通过TypeToken获取泛型参数的类型
JsonBean jsonBean = gson.fromJson(json, type);
然后想拿数据就很简单了，直接在jsonBean里面取就可以了！
如果需要解析的Json嵌套了很多层，同样可以可以定义一个嵌套很多层内部类的Bean，需要细心的对照Json字段来定义。
下面我将以一个具体的列子来说明通过Gson方式解析复杂的json数据
1.将要解析的数据如下面的格式
{
"error": 0,
"status": "success",
"date": "2014-05-10",
"results": [
{
"currentCity": "南京",
"weather_data": [
{
"date": "周六(今天, 实时：19℃)",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/dayu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/dayu.png",
"weather": "大雨",
"wind": "东南风5-6级",
"temperature": "18℃"
},
{
"date": "周日",
"dayPictureUrl": "http://api.map.baidu.com/images/weather/day/zhenyu.png",
"nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",
"weather": "阵雨转多云",
"wind": "西北风4-5级",
"temperature": "21 ~ 14℃"
}
]
}
]
}
2.必须定义如下一些的javaBean数据
Status.java
[java] view
plain copy
public class Status
{
private String error;
private String status;
private String date;
private List<Results> results;
public String getError()
{
return error;
}
public void setError(String error)
{
this.error = error;
}
public String getStatus()
{
return status;
}
public void setStatus(String status)
{
this.status = status;
}
public String getDate()
{
return date;
}
public void setDate(String date)
{
this.date = date;
}
public List<Results> getResults()
{
return results;
}
public void setResults(List<Results> results)
{
this.results = results;
}
@Override
public String toString()
{
return "Status [error=" + error + ", status=" + status
+ ", date=" + date + ", results=" + results + "]";
}
</span>
Results.java
public class Results
{
private String currentCity;
private List<Weather> weather_data;
public String getCurrentCity()
{
return currentCity;
}
public void setCurrentCity(String currentCity)
{
this.currentCity = currentCity;
}
public List<Weather> getWeather_data()
{
return weather_data;
}
public void setWeather_data(List<Weather> weather_data)
{
this.weather_data = weather_data;
}
@Override
public String toString()
{
return "Results [currentCity=" + currentCity + ", weather_data="
+ weather_data + "]";
}
Weather.java
public class Weather {
private String date;
private String dayPictureUrl;
private String nightPictureUrl;
private String weather;
private String wind;
private String temperature;
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getDayPictureUrl() {
return dayPictureUrl;
}
public void setDayPictureUrl(String dayPictureUrl) {
this.dayPictureUrl = dayPictureUrl;
}
public String getNightPictureUrl() {
return nightPictureUrl;
}
public void setNightPictureUrl(String nightPictureUrl) {
this.nightPictureUrl = nightPictureUrl;
}
public String getWeather() {
return weather;
}
public void setWeather(String weather) {
this.weather = weather;
}
public String getWind() {
return wind;
}
public void setWind(String wind) {
this.wind = wind;
}
public String getTemperature() {
return temperature;
}
public void setTemperature(String temperature) {
this.temperature = temperature;
}
@Override
public String toString() {
return "Weather [date=" + date + ", dayPictureUrl="
+ dayPictureUrl + ", nightPictureUrl="
+ nightPictureUrl + ", weather=" + weather
+ ", wind=" + wind + ", temperature=" + temperature
+ "]";
}
然后具体的javabean定义好了就将解析数据了，下面就是我的解析数据类
public class MainActivity extends Activity
{
private Button tojson;
RequestQueue mQueue;
StringRequest stringRequest;
Gson gson;
String str;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tojson = (Button)findViewById(R.id.tojson);
gson = new Gson();
mQueue = Volley.newRequestQueue(MainActivity.this);
//http://10.19.20.12/upgrade/test.txt是测试使用的json数据
stringRequest = new StringRequest("http://10.19.20.12/upgrade/test.txt",
new Response.Listener<String>()
{
@Override
public void onResponse(String response)
{
Log.d("TAG", response);
System.out.println("response="+response);
Status status = gson.fromJson(response, Status.class);
System.out.println("status="+status);
System.out.println("-------------------------------------");
List<Results> result = status.getResults();
System.out.println("result="+result);
}
},
new Response.ErrorListener()
{
@Override
public void onErrorResponse(VolleyError error)
{
Log.e("TAG", error.getMessage(), error);
}
});
tojson.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
mQueue.add(stringRequest);
}
});
}
}
其中上面的RequestQueue是开源网络库Volley的使用，如果你对该库的使用还不熟悉的话可以参考http://blog.csdn.net/guolin_blog/article/details/17482095，该作者对Volley库的使用讲解得非常的细致和深入
大家可以仔细的去拜读。
转载自：http://blog.csdn.net/lanxingfeifei/article/details/50736955
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