java无法反序列化启动数组JSON/Spring MVC之外的对象实例

Question

我编写了一个简单的web应用程序，可以连接到我的数据库。我在安卓上有一个应用程序，它发送一个请求来获取数据库的内容

一开始，我使用了一个普通的字符串，但很快意识到它没有给我任何东西，我必须使用hibernate创建的类对象

我的任务有一个代码：

private class  DatabaseLoaderTask extends AsyncTask<Void, Void, Void> {

        TextView testText;
        TacticsEntity content = new TacticsEntity();

        @Override
        protected void onPreExecute() {
            testText = (TextView) findViewById(R.id.textView);
        }

        @Override
        protected Void doInBackground(Void... urls) {
            RestTemplate restTemplate = new RestTemplate();
            content = restTemplate.getForObject("http://192.168.0.105:8080/SpringMVCApp/api/tactics", TacticsEntity.class);
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    testText.setText(content.getId());
                }
            });
            return null;
        }
    }

但当我运行我的应用程序时，我出现了以下错误：

java.lang.RuntimeException: An error occured while executing doInBackground()
            at 安卓.os.AsyncTask$3.done(AsyncTask.java:300)
            at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
            at java.util.concurrent.FutureTask.run(FutureTask.java:242)
            at 安卓.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)
     Caused by: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not deserialize instance of com.example.jarek.stratcaller.TacticsEntity out of START_ARRAY token
            at [Source: buffer(com.安卓.okhttp.internal.http.HttpConnection$ChunkedSource@2325082d).inputStream(); line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of com.example.jarek.stratcaller.TacticsEntity out of START_ARRAY token
            at [Source: buffer(com.安卓.okhttp.internal.http.HttpConnection$ChunkedSource@2325082d).inputStream(); line: 1, column: 1]
            at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.readJavaType(MappingJackson2HttpMessageConverter.java:182)
            at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.read(MappingJackson2HttpMessageConverter.java:174)
            at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:89)
            at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:544)
            at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:499)
            at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:264)
            at com.example.jarek.stratcaller.MainMenuActivity$DatabaseLoaderTask.doInBackground(MainMenuActivity.java:31)
            at com.example.jarek.stratcaller.MainMenuActivity$DatabaseLoaderTask.doInBackground(MainMenuActivity.java:18)
            at 安卓.os.AsyncTask$2.call(AsyncTask.java:288)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at 安卓.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)
     Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of com.example.jarek.stratcaller.TacticsEntity out of START_ARRAY token
            at [Source: buffer(com.安卓.okhttp.internal.http.HttpConnection$ChunkedSource@2325082d).inputStream(); line: 1, column: 1]
            at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:854)
            at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:850)
            at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromArray(BeanDeserializerBase.java:1258)
            at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:155)
            at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:134)
            at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3702)
            at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2798)
            at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.readJavaType(MappingJackson2HttpMessageConverter.java:179)
            at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.read(MappingJackson2HttpMessageConverter.java:174)
            at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:89)
            at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:544)
            at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:499)
            at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:264)
            at com.example.jarek.stratcaller.MainMenuActivity$DatabaseLoaderTask.doInBackground(MainMenuActivity.java:31)
            at com.example.jarek.stratcaller.MainMenuActivity$DatabaseLoaderTask.doInBackground(MainMenuActivity.java:18)
            at 安卓.os.AsyncTask$2.call(AsyncTask.java:288)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at 安卓.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)

在我看来，这可能是因为我的Web应用程序返回了一个数组：

  @ResponseBody
    @RequestMapping(value = "/api/tactics", method = RequestMethod.GET, produces = "application/json; charset=utf-8")
    public Object[] listTacticsJson(ModelMap model) throws JSONException {
        return tacticsRepository.findAll().toArray();
    }

TacticsRepository类：

package com.springapp.mvc;

import org.springframework.data.jpa.repository.JpaRepository;

public interface TacticsRepository extends JpaRepository<TacticsEntity, Long> {
}

有办法解决吗