Json的生成和解析

json是常见的数据格式，生成和解析是常用的操作。Android中，默认提供orgJson供我们使用，除此之外，google也提供了Gson库方便我们开发。

Json样例类

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package com.fxb.jsontest;   import android.content.Context; import android.util.Log; import android.widget.Toast; import com.google.gson.Gson; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject;     public class JsonUtils {       public static String createJson(){         try {             JSONObject json = new JSONObject();             json.put("key1", "value1");             json.put("key2", "value2");               JSONObject json1 = new JSONObject();             json1.put("key3", "value3");             json1.put("key4", "value4");             json.put("child1", json1);               JSONObject json2 = new JSONObject();             json2.put("key5", "value5");             json2.put("key6", "value6");             json1.put("child2", json2);               JSONObject json3 = new JSONObject();             json3.put("key7", "value7");             json3.put("key8", "value8");             json2.put("child2", json3);               JSONArray arr = new JSONArray();             JSONObject json4 = new JSONObject();             json4.put("key9", "value9");             json4.put("key10", "value10");             arr.put(json4);               JSONObject json5 = new JSONObject();             json5.put("key11", "value11");             json5.put("key12", "value12");             arr.put(json5);               json3.put("child3", arr);   //            Log.i("JsonTest", json.toString());             return json.toString();         } catch (JSONException e) {             e.printStackTrace();             return null;         }     }       public static void orgJsonTest(Context context){         String str = "{\"key1\":\"value1\",\"key2\":\"value2\",\"child1\":{\"key3\":\"value3\",\"key4\":\"value4\",\"child2\":{\"key5\":\"value5\",\"key6\":\"value6\",\"child3\":{\"key7\":\"value7\",\"key8\":\"value8\",\"child4\":[{\"key9\":\"value9\",\"key10\":\"value10\"},{\"key11\":\"value11\",\"key12\":\"value12\"}]}}}}";         try {             JSONObject jsonRoot = new JSONObject(str);             JSONObject jsonChild3 = jsonRoot.getJSONObject("child1").getJSONObject("child2").getJSONObject("child3");             if(jsonChild3 != null){                 String str7 = jsonChild3.getString("key7");                 String str8 = jsonChild3.getString("key8");                   JSONArray jsonArr = jsonChild3.getJSONArray("child4");                 JSONObject jsonChild4_1 = jsonArr.getJSONObject(0);                 String str9 = jsonChild4_1.getString("key9");                 String str10 = jsonChild4_1.getString("key10");   //                Log.i(MainActivity.TAG, "str7:"+str7+", str8:"+str8); //                Log.i(MainActivity.TAG, "str9:"+str9+", str10:"+str10);                 String strShow = "str7:"+str7+", str8:"+str8 + "\n"+"str9:"+str9+", str10:"+str10;                 showToast(context, strShow);             }             else{                 Log.i(MainActivity.TAG, "empty");             }         } catch (JSONException e) {             e.printStackTrace();         }     }       public static void gsonTest(Context context){         Gson gson = new Gson();         int i = gson.fromJson("100", int.class);         double d = gson.fromJson("1.234", double.class);         boolean b = gson.fromJson("true", boolean.class);           final String strPerson = "{\"id\":5678,\"name\":\"Jack\",\"isWell\":\"true\",\"adress\":\"beijing\"}";           Person person = gson.fromJson(strPerson, Person.class);         Toast.makeText(context, "i:" + i + "\nd:" + d + "\nb:" + b + "\nperson\n" + person.show(), Toast.LENGTH_SHORT).show();       }       public static void showToast(Context context, String str){         Toast.makeText(context, str, Toast.LENGTH_SHORT).show();     }         public static class Person{         private int id;         private String name;         private boolean isWell;         private String adress;           public String show(){             return "id="+id+", isWell="+ isWell +", adress="+adress;         }     }   }

测试Activity类

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package com.fxb.jsontest;   import android.app.Activity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button;   public class MainActivity extends Activity implements View.OnClickListener {       public static final String TAG = "JsonTest";     private Button btnCreateJson, btnOrgJson, btnGson, btnFastJson;       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         initView();     }       private void initView(){         btnCreateJson = (Button)findViewById(R.id.btnCreateJson);         btnOrgJson = (Button)findViewById(R.id.btnOrgJson);         btnGson = (Button)findViewById(R.id.btnGson);         btnFastJson = (Button)findViewById(R.id.btnFastJson);           btnCreateJson.setOnClickListener(this);         btnOrgJson.setOnClickListener(this);         btnGson.setOnClickListener(this);         btnFastJson.setOnClickListener(this);     }       @Override     public void onClick(View v) {         if(v == btnCreateJson){             String str = JsonUtils.createJson();             Log.i(TAG, str);         }         else if(v == btnOrgJson){             JsonUtils.orgJsonTest(this);         }         else if(v == btnGson){           }         else if(v == btnFastJson){           }     } }

　　样例中，成功创建了json字符串，并实现了解析。