将整数转换为布尔值 [英] Convert ints to booleans

问题描述

有没有办法将int / short值转换为布尔值？我收到的JSON如下所示：

  {is_user：0，is_guest：0} 
  

我试图将它序列化为如下所示的类型：

  class UserInfo {
 
 @SerializedName（is_user）
 private boolean isUser; 
 
 @SerializedName（is_guest）
 private boolean isGuest; 
 
 / * ... * / 
} 
  

我可以让Gson将这些int / short域转换为布尔值吗？ 解决方案

首先获取Gson 2.2.2或更高版本。早期版本（包括2.2）不支持原始类型的类型适配器。接下来，编写一个将整数转换为布尔值的类型适配器：

  private static final TypeAdapter< Boolean> booleanAsIntAdapter = new TypeAdapter< Boolean>（）{
 @Override public void write（JsonWriter out，Boolean value）throws IOException {$ b $ if（value == null）{
 out.nullValue（） ; 
} else {
 out.value（value）; 
 
 
 @Override public Boolean read（JsonReader in）throws IOException {
 JsonToken peek = in.peek（）; 
 switch（peek）{
 case BOOLEAN：
 return in.nextBoolean（）; 
 case NULL：
 in.nextNull（）; 
返回null; 
 case NUMBER：
 return in.nextInt（）！= 0; 
 case STRING：
 return Boolean.parseBoolean（in.nextString（））; 
默认值：
抛出新的IllegalStateException（期望的BOOLEAN或NUMBER，但是+ peek）; 
} 
} 
}; 
  

...然后使用此代码创建Gson实例：

  Gson gson = new GsonBuilder（）
 .registerTypeAdapter（Boolean.class，booleanAsIntAdapter）
 .registerTypeAdapter（boolean.class，booleanAsIntAdapter） 
 .create（）; 
  

Is there a way that I can convert int/short values to booleans? I'm receiving JSON that looks like this:

{ is_user: "0", is_guest: "0" }

I'm trying to serialize it into a type that looks like this:

class UserInfo {

    @SerializedName("is_user")
    private boolean isUser;

    @SerializedName("is_guest")
    private boolean isGuest;

    /* ... */
}

How can I make Gson translate these int/short fields into booleans?

解决方案

Start by getting Gson 2.2.2 or later. Earlier versions (including 2.2) don't support type adapters for primitive types. Next, write a type adapter that converts integers to booleans:

private static final TypeAdapter<Boolean> booleanAsIntAdapter = new TypeAdapter<Boolean>() {
  @Override public void write(JsonWriter out, Boolean value) throws IOException {
    if (value == null) {
      out.nullValue();
    } else {
      out.value(value);
    }
  }
  @Override public Boolean read(JsonReader in) throws IOException {
    JsonToken peek = in.peek();
    switch (peek) {
    case BOOLEAN:
      return in.nextBoolean();
    case NULL:
      in.nextNull();
      return null;
    case NUMBER:
      return in.nextInt() != 0;
    case STRING:
      return Boolean.parseBoolean(in.nextString());
    default:
      throw new IllegalStateException("Expected BOOLEAN or NUMBER but was " + peek);
    }
  }
};

... and then use this code to create the Gson instance:

  Gson gson = new GsonBuilder()
      .registerTypeAdapter(Boolean.class, booleanAsIntAdapter)
      .registerTypeAdapter(boolean.class, booleanAsIntAdapter)
      .create();

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