我目前无法连接到android上的web服务。我使用jackson-core / databind / annotation-2.2.4和Spring RESTWebService。如果我从浏览器访问URL，我可以看到JSON响应:(服务器返回List \ Shop \看起来像：）
[{"id":1,"product_tmpl_id":1,"message_last_post":null,"ean13":null,"default_code":null,"name_template":"Service","image_variant":null,"active":true,"create_uid":1,"create_date":1463633587963,"write_date":1463633587963,"write_uid":1}]
从客户端端点（Android应用程序）收到此错误消息：
06-14 15:18:34.702 14597-14639/? E/MainActivity: Could not read JSON: Can not deserialize instance of stpi.com.rest.Products out of START_ARRAY token
at [Source: com.android.okhttp.internal.http.HttpTransport$ChunkedInputStream@41da0398; line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of stpi.com.rest.Products out of START_ARRAY token
at [Source: com.android.okhttp.internal.http.HttpTransport$ChunkedInputStream@41da0398; line: 1, column: 1]
org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not deserialize instance of stpi.com.rest.Products out of START_ARRAY token
at [Source: com.android.okhttp.internal.http.HttpTransport$ChunkedInputStream@41da0398; line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of stpi.com.rest.Products out of START_ARRAY token
at [Source: com.android.okhttp.internal.http.HttpTransport$ChunkedInputStream@41da0398; line: 1, column: 1]
at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.readInternal(MappingJackson2HttpMessageConverter.java:126)
at org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:147)
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:76)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:484)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:439)
at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:237)
at stpi.com.rest.MainActivity$HttpRequestTask.doInBackground(MainActivity.java:83)
at stpi.com.rest.MainActivity$HttpRequestTask.doInBackground(MainActivity.java:76)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$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:841)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of stpi.com.rest.Products out of START_ARRAY token
at [Source: com.android.okhttp.internal.http.HttpTransport$ChunkedInputStream@41da0398; line: 1, column: 1]
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:691)
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:685)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromArray(BeanDeserializerBase.java:1215)
at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:151)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:126)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2993)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2158)
at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.readInternal(MappingJackson2HttpMessageConverter.java:123)
... 13 more
06-14 15:18:34.707 14597-14597/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: stpi.com.rest, PID: 14597
java.lang.NullPointerException
at stpi.com.rest.MainActivity$HttpRequestTask.onPostExecute(MainActivity.java:96)
at stpi.com.rest.MainActivity$HttpRequestTask.onPostExecute(MainActivity.java:76)
at android.os.AsyncTask.finish(AsyncTask.java:632)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
我在Android应用中的主要活动：
package stpi.com.rest;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.client.RestTemplate;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
@Override
protected void onStart() {
super.onStart();
new HttpRequestTask().execute();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_refresh) {
new HttpRequestTask().execute();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.content_main, container, false);
return rootView;
}
}
private class HttpRequestTask extends AsyncTask<Void, Void, Products> {
@Override
protected Products doInBackground(Void... params) {
try {
final String url = "http://164.164.36.11:443/seis/productController/getProduct";
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
Products greeting = restTemplate.getForObject(url, Products.class);
return greeting;
} catch (Exception e) {
Log.e("MainActivity", e.getMessage(), e);
}
return null;
}
@Override
protected void onPostExecute(Products greeting) {
TextView greetingIdText = (TextView) findViewById(R.id.id_value);
TextView greetingContentText = (TextView) findViewById(R.id.content_value);
greetingIdText.setText(greeting.getId());
greetingContentText.setText(greeting.getname_template());
greetingContentText.setText(greeting.getproduct_tmpl_id());
greetingContentText.setText(greeting.getmessage_last_post());
greetingContentText.setText(greeting.getean13());
greetingContentText.setText(greeting.getdefault_code());
greetingContentText.setText(greeting.getimage_variant());
greetingContentText.setText(greeting.getactive());
greetingContentText.setText(greeting.getcreate_uid());
greetingContentText.setText(greeting.getcreate_date());
greetingContentText.setText(greeting.getwrite_date());
greetingContentText.setText(greeting.getwrite_uid());
}
}
}
这是我在其他类产品中添加id，rest变量和getter。
package stpi.com.rest;
/**
* Created by Admin on 6/14/2016.
*/
public class Products {
private String id;
private String name_template;
private String product_tmpl_id;
private String message_last_post;
private String ean13;
private String default_code;
private String image_variant;
private String active;
private String create_uid;
private String create_date;
private String write_date;
private String write_uid;
public String getId() {
return this.id;
}
public String getname_template() {
return this.name_template;
}
public String getproduct_tmpl_id() {
return this.product_tmpl_id;
}
public String getmessage_last_post() {
return this.message_last_post;
}
public String getean13() {
return this.ean13;
}
public String getdefault_code() {
return this.default_code;
}
public String getimage_variant() {
return this.image_variant;
}
public String getactive() {
return this.active;
}
public String getcreate_uid() {
return this.create_uid;
}
public String getcreate_date() {
return this.create_date;
}
public String getwrite_date() {
return this.write_date;
}
public String getwrite_uid() {
return this.write_uid;
}
}
有人可以帮我解决这个问题吗？
答案 0 :(得分：1)
当我们获取对象集合以获取单个对象时，我使用了Product []并且它正常工作。
private class HttpRequestTask extends AsyncTask<Void, Void, Products> {
Products[] greeting;
@Override
protected Products doInBackground(Void... params) {
try {
final String url = "http://164.164.36.11:443/seis/productController/getProduct";
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
greeting = restTemplate.getForObject(url, Products[].class);
return greeting[0];
} catch (Exception e) {
Log.e("MainActivity", e.getMessage(), e);
}
return null;
}
@Override
protected void onPostExecute(Products greeting) {
TextView greetingIdText = (TextView) findViewById(R.id.id_value);
TextView greetingContentText = (TextView) findViewById(R.id.content_value);
Log.i("post exe active", greeting.getname_template());
greetingIdText.setText(greeting.getId());
greetingContentText.setText(greeting.getname_template());