Gson解析空字符串异常的处理

时间:2022-11-26 15:32:18

面对一些不规范的json,我们的gson解析经常会抛出各种异常导致app崩溃,这里可以采取一些措施来避免。

我们期望在后台返回的json异常时,也能解析成功,空值对应的转换为默认值,如:newsId=0;
这里排除掉后台开发人员输出时给你做矫正,还是得靠自己啊---

我们写一个针对int值的类型转换器,需要实现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")) {
//定义为int类型,如果后台返回""或者null,则返回0
return ;
}
} 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类型

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")) {
        //定义为long类型,如果后台返回""或者null,则返回0
return ;
}
} 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类型

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")) {
          //定义为double类型,如果后台返回""或者null,则返回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)//设置网络访问框架
.addConverterFactory(GsonConverterFactory.create(buildGson()))//添加json转换框架
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())//让Retrofit支持RxJava
.baseUrl(baseUrl)
.build(); /**
* 增加后台返回""和"null"的处理
* 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;
}