高效正确的使用Gson

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gson的基本用法：

反序列化:将json转换为类Gson gson = new Gson();Data i = gson.fromJson("100", Data.class); <pre class="html" name="code"> List<对象类>list=gson.fromJson(json，new TypeToken<List<Food>>() {}.getType());   <span style="color:#33cc00;">//将json转换为集合</span>

<pre class="hljs java"><code class="java">String[] strings = gson.fromJson(jsonArray, String[].class);</code>            <span style="color:#33cc00;">//将json转换为数组</span>

序列化:将类转换为jsonGson gson = new Gson();String jsonNumber = gson.toJson(100);       // 100

@SerializedNamer注解：将JSON字段的值解析到emailAddress中

//设置单个字段名@SerializedName("email_address")public String emailAddress;<span style="color:#33cc00;">  //当alternate数组中出现任意一个时，都可以得到正确结构</span>@SerializedName(value = "emailAddress", alternate = {"email", "email_address"})public String emailAddress;

泛型：

直接看例子

public class UserResponse {    public int code;    public String message;    public User data;}public class UserResponse {    public int code;    public String message;    public Client data;}<pre class="html" name="code">public class Result<T> {    public int code;    public String message;    public T data;}

//请求数据

<pre class="hljs php"><code class="php">Type userListType = <span class="hljs-keyword">new</span> TypeToken<Result<<span class="hljs-keyword">List</span><User>>>(){}.getType();Result<<span class="hljs-keyword">List</span><User>> userListResult = gson.fromJson(json,userListType);<span class="hljs-keyword">List</span><User> users = userListResult.data;</code>

TypeAdapter：接管序列化和反序列化过程

自定义gson解析的过程，并且会大大提高性能

 Gson gson=new GsonBuilder().registerTypeAdapter(Tb.class, new TypeAdapter<Tb>() {        @Override        public void write(JsonWriter jsonWriter, Tb tb) throws IOException {  <span style="color:#33cc00;">//将对象转为字符串</span>            jsonWriter.beginObject();            jsonWriter.name("name").value(tb.name);            jsonWriter.name("age").value(tb.age);            jsonWriter.endObject();        }        @Override        public Tb read(JsonReader jsonReader) throws IOException {               <span style="color:#33cc00;"> //将字符串转为类</span>            Tb user = new Tb();            jsonReader.beginObject();            while (jsonReader.hasNext()) {                switch (jsonReader.nextName()) {                    case "name":                        user.name = jsonReader.nextString();                        break;                    case "age":                        user.age = jsonReader.nextInt();                        break;                }            }            jsonReader.endObject();            return user;        }    }).create();        Log.e("dddd",gson.toJson(new Tb("哈哈",20)));

注册了 TypeAdapter之后，@SerializedName 、FieldNamingStrategy、Since、Until、Expos都失去了效果，只会调用我们实现的UserTypeAdapter.write(JsonWriter, User) 方法

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