Gson解析空字符串異常的處理

面對一些不規範的json,咱們的gson解析常常會拋出各類異常致使app崩潰,這裏能夠採起一些措施來避免。

咱們指望在後臺返回的json異常時,也能解析成功,空值對應的轉換爲默認值,如:newsId=0;
這裏排除掉後臺開發人員輸出時給你作矯正,仍是得靠本身啊---

咱們寫一個針對int值的類型轉換器,須要實現Gson的JsonSerializer<T>接口和JsonDeserializer<T>,即序列化和反序列化接口

public class IntegerDefault0Adapter implements JsonSerializer<Integer>, JsonDeserializer<Integer> {

    @Override
    public Integer deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {
        try {
            if (json.getAsString().equals("") || json.getAsString().equals("null")) {
                //定義爲int類型,若是後臺返回""或者null,則返回0
                return 0;
            }
        } catch (Exception ignore) {
        }
        try {
            return json.getAsInt();
        } catch (NumberFormatException e) {
            throw new JsonSyntaxException(e);
        }
    }
 
    @Override
    public JsonElement serialize(Integer src, Type typeOfSrc, JsonSerializationContext context) {
        return new JsonPrimitive(src);
    }
}

同理Long類型

public class LongDefault0Adapter implements JsonSerializer<Long>, JsonDeserializer<Long> {

    @Override
    public Long deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {
        try {
            if (json.getAsString().equals("") || json.getAsString().equals("null")) {
　　　　　　　    //定義爲long類型,若是後臺返回""或者null,則返回0
                return 0;
            }
        } catch (Exception ignore) {
        }
        try {
            return json.getAsLong();
        } catch (NumberFormatException e) {
            throw new JsonSyntaxException(e);
        }
    }
 
    @Override
    public JsonElement serialize(Long src, Type typeOfSrc, JsonSerializationContext context) {
        return new JsonPrimitive(src);
    }
}

 同理Double類型

public class DoubleDefault0Adapter implements JsonSerializer<Double>, JsonDeserializer<Double> {

    @Override
    public Double deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) 
            throws JsonParseException {
        try {
            if (json.getAsString().equals("") || json.getAsString().equals("null")) {
　　　　　　　　　 //定義爲double類型,若是後臺返回""或者null,則返回0.00
                return 0.00;
        　　 }
        } catch (Exception ignore) {
        }
        try {
            return json.getAsDouble();
        } catch (NumberFormatException e) {
            throw new JsonSyntaxException(e);
        }
    }
 
    @Override
    public JsonElement serialize(Double src, Type typeOfSrc, JsonSerializationContext context) {
        return new JsonPrimitive(src);
    }
}

 使用方法

return new Retrofit.Builder()
       .client(okHttpClient)//設置網絡訪問框架
       .addConverterFactory(GsonConverterFactory.create(buildGson()))//添加json轉換框架
       .addCallAdapterFactory(RxJavaCallAdapterFactory.create())//讓Retrofit支持RxJava
       .baseUrl(baseUrl)
       .build();
 
/**
 * 增長後臺返回""和"null"的處理
 * 1.int=>0
 * 2.double=>0.00
 * 3.long=>0L
 *
 * @return
 */
public static Gson buildGson() {
    if (gson == null) {
        gson = new GsonBuilder()
                .registerTypeAdapter(Integer.class, new IntegerDefault0Adapter())
                .registerTypeAdapter(int.class, new IntegerDefault0Adapter())
                .registerTypeAdapter(Double.class, new DoubleDefault0Adapter())
                .registerTypeAdapter(double.class, new DoubleDefault0Adapter())
                .registerTypeAdapter(Long.class, new LongDefault0Adapter())
                .registerTypeAdapter(long.class, new LongDefault0Adapter())
                .create();
    }
    return gson;
}