Question

我正在调用一个服务，它将响应作为json返回，并使用Gson将它们转换为Java对象。在50个案例中的47个案例中，我得到了Java对象，但在其中3个案例中，我收到以下错误：

com.google.gson.JsonSyntaxException: Expecting number, got: STRING
    at com.google.gson.internal.bind.TypeAdapters$11.read(TypeAdapters.java:304)
    at com.google.gson.internal.bind.TypeAdapters$11.read(TypeAdapters.java:293)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:93)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:172)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:40)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:81)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:93)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:172)
    at com.google.gson.Gson.fromJson(Gson.java:795)
    at com.google.gson.Gson.fromJson(Gson.java:761)
    at com.google.gson.Gson.fromJson(Gson.java:710)
    at com.google.gson.Gson.fromJson(Gson.java:682)

在这里可以看到一个失败的json响应：http://ec2-50-112-212-186.us-west-2.compute.amazonaws.com/ske.json。我的Java bean如下：

import java.util.List;

import com.google.gson.annotations.SerializedName;

public class WordSketch{

    @SerializedName("Gramrels")
    private List<Gramrel> gramrels;

    public List<Gramrel> getGramrels(){
        return this.gramrels;
    }
    public void setGramrels(List<Gramrel> gramrels){
        this.gramrels = gramrels;
    }

    public static class Gramrel {

        @SerializedName("Words")
        private List<Word> words;
        private Number count;
        private String name;
        private Number score;
        private Number seek;

        public List<Word> getWords(){
            return this.words;
        }
        public void setWords(List<Word> words){
            this.words = words;
        }
        public Number getCount(){
            return this.count;
        }
        public void setCount(Number count){
            this.count = count;
        }
        public String getName(){
            return this.name;
        }
        public void setName(String name){
            this.name = name;
        }
        public Number getScore(){
            return this.score;
        }
        public void setScore(Number score){
            this.score = score;
        }
        public Number getSeek(){
            return this.seek;
        }
        public void setSeek(Number seek){
            this.seek = seek;
        }
    }

    public static class Word {
        private Number count;
        private Number id;
        private String lempos;
        private Number score;
        private Number seek;
        private String word;

        public Number getCount(){
            return this.count;
        }
        public void setCount(Number count){
            this.count = count;
        }
        public Number getId(){
            return this.id;
        }
        public void setId(Number id){
            this.id = id;
        }
        public String getLempos(){
            return this.lempos;
        }
        public void setLempos(String lempos){
            this.lempos = lempos;
        }
        public Number getScore(){
            return this.score;
        }
        public void setScore(Number score){
            this.score = score;
        }
        public Number getSeek(){
            return this.seek;
        }
        public void setSeek(Number seek){
            this.seek = seek;
        }
        public String getWord(){
            return this.word;
        }
        public void setWord(String word){
            this.word = word;
        }
    }
}

，实际的gson调用是gson.fromJson(json, WordSketch.class)。

任何人都可以指出什么是错的，或者至少让我对如何调试（快速）有所了解，因为我不知道json的哪个部分，gson失败了？

非常感谢，

Answer 1

通过观察你的JSON，我意识到一些字段通常有一个数值，有时候它们有一个空字符串作为值。

例如，响应中的第三个 gramrel 是：

{
    "count": "",
    "colbreak": 1,
    "name": "unary rels",
    "score": "",
    "Words": [
        {
            "count": 6,
            "word": "prp_għaċ-",
            "name": "prp_għaċ-",
            "score": 9.1,
            "Words": [ ],
            "seek": 2231297
        }
    ],
    "seek": 0
},

在课堂上，您定义了count和score类型Number，GSON会抱怨！

编辑：我建议您让班级中的所有字段都为String类型，然后您可以根据需要进行转换...我的意思是，您可以使用您只是作为响应包类编写的类，然后从该响应类创建实际的类...

WordSketch ws = gson.fromJson(json, WordSketch.class);
for (Gramrel g in ws.getGramrels) {
    Number count = //convert the String into Number...
    //etc...
    MyGrammel myGrammel = new MyGrammel(count, ...);
}

在此示例中，您的Gramrel类只是包装响应的临时类，MyGramrel是您将使用的实际类（具有类型Number）的属性....

将json解析为java对象时出错：期待数字，得到字符串

1 个答案: