Android 中Volley二次封装并实现网络请求缓存

Android 中Volley二次封装并实现网络请求缓存

Android目前很多同学使用Volley请求网络数据，但是Volley没有对请求过得数据进行缓存，因此需要我们自己手动缓存。一下就是我的一种思路，仅供参考

具体使用方法为：

HashMap params = new HashMap<>();
params.put("id", "1");
params.put("user", "mcoy");
new NetWorkHelper(getActivity()).jacksonMethodRequest
("method_id", params, new TypeReference>(){}, handler, msgId);

NetWorkHelper---对Volley的封装，首先调用CacheManager.get(methodName, params);方法获取缓存中的数据，如果数据为null，

则继续发送网络请求。

 
public final class NetWorkHelper { 
 
  private NetWorkManager netWorkUtils; 
 
  public NetWorkHelper(Context context){ 
    netWorkUtils = new NetWorkManager(context); 
  } 
 
  public static final String COMMON_ERROR_MSG = "连接超时，请稍后重试"; 
  public static final int COMMON_ERROR_CODE = 2; 
 
 
   
  public void jacksonMethodRequest(final String methodName,final HashMap params,TypeReference javaType, final Handler handler,final int msgId){ 
 
    ResponseListener listener =  new ResponseListener(){ 
      @Override 
      public void onResponse(Object response, boolean isCache) { 
 PrintLog.log(response.toString()); 
 if (isCache){ 
   CacheManager.put(methodName, params, response); 
 } 
 if (handler != null) { 
   Message message = handler.obtainMessage(); 
   message.what = msgId; 
   message.obj = response; 
   handler.sendMessage(message); 
 } 
      } 
    }; 
 
    Object respone = CacheManager.get(methodName, params); 
    if(respone != null){ 
      listener.onResponse(respone,false); 
      return; 
    } 
 
    HashMap allParams = Config.setSign(true); 
    allParams.putAll(params); 
    Response.ErrorListener errorListener = new Response.ErrorListener() { 
      @Override 
      public void onErrorResponse(VolleyError error) { 
 error.printStackTrace(); 
 if (handler != null) { 
   Message message = handler.obtainMessage(); 
   message.what = msgId; 
   message.obj = COMMON_ERROR_MSG; 
   handler.sendMessage(message); 
 } 
      } 
    }; 
    netWorkUtils.jacksonRequest(getUrl(methodName), allParams,javaType, listener, errorListener); 
  } 
 
   
  public void urlRequest(String url,HashMap params,JsonParser jsonParser,final Handler handler,final int msgId){ 
 
    request(url, true, params, jsonParser, handler, msgId); 
  } 
 
   
  public void methodRequest(String methodName, final HashMap params,final JsonParser jsonParser,final Handler handler,final int msgId){ 
    request(getUrl(methodName),true,params,jsonParser,handler,msgId); 
  } 
 
   
  public void methodRequest(String methodName, boolean isLogin,final HashMap params,final JsonParser jsonParser,final Handler handler,final int msgId){ 
    request(getUrl(methodName),isLogin,params,jsonParser,handler,msgId); 
  } 
 
 
 
 
  private void request(final String url, boolean isLogin,final HashMap params,final JsonParser jsonParser,final Handler handler,final int msgId){ 
    final HashMap allParams = Config.setSign(isLogin); 
    allParams.putAll(params); 
    Response.Listener listener = new Response.Listener() { 
      @Override 
      public void onResponse(String response) { 
  
 Object result; 
 PrintLog.log(response); 
 if (jsonParser != null ) { 
   jsonParser.json2Obj(response); 
   jsonParser.temple.description = jsonParser.temple.getResultDescription(); 
   result = jsonParser.temple; 
 } else { 
   ReturnTemple temple = new ReturnTemple(); 
   temple.issuccessful = false; 
   temple.description = COMMON_ERROR_MSG; 
   temple.result = -100; 
   result = temple; 
 } 
 if (handler != null) { 
   Message message = handler.obtainMessage(); 
   message.what = msgId; 
   message.obj = result; 
   handler.sendMessage(message); 
 } 
      } 
    }; 
 
    Response.ErrorListener errorListener = new Response.ErrorListener() { 
      @Override 
      public void onErrorResponse(VolleyError error) { 
 Object result; 
 if (jsonParser != null) { 
   ReturnTemple temple = new ReturnTemple(); 
   temple.issuccessful = false; 
   temple.description = COMMON_ERROR_MSG; 
   temple.result = COMMON_ERROR_CODE; 
   result = temple; 
 } else { 
   result = COMMON_ERROR_MSG; 
 } 
 if (handler != null) { 
   Message message = handler.obtainMessage(); 
   message.what = msgId; 
   message.obj = result; 
   handler.sendMessage(message); 
 } 
      } 
    }; 
    netWorkUtils.request(url, allParams, listener, errorListener); 
  } 
 
   
  private String getUrl(String methodName){ 
    String url = Config.getUrl(); 
    if (!StringUtil.isNullOrEmpty(methodName)) { 
      url = url + "?method=" + methodName; 
    } 
    return url; 
  } 
}

CacheManager---将针对某一method所请求的数据缓存到本地文件当中，主要是将CacheRule写到本地文件当中

 
public final class CacheManager { 
   
  private static HashMap> methodKeys; 
  private static final String keyFileName = "keys.pro"; 
 
   
  public static void readCacheKey() { 
    methodKeys = (HashMap>) readObject(keyFileName); 
    if (methodKeys == null) { 
      methodKeys = new HashMap>(); 
    } 
  } 
 
   
  public static void put(String method, HashMap params, Object object) { 
    long expireTime = CacheConfig.getExpireTime(method); 
    if (expireTime <= 0 || methodKeys == null) {//有效时间小于0，则不需要缓存 
      return; 
    } 
    String key = createKey(method, params); 
    if (methodKeys.containsKey(method)) { 
      ArrayList keys = methodKeys.get(method); 
      keys.add(key); 
    } else { 
      ArrayList keys = new ArrayList<>(); 
      keys.add(key); 
      methodKeys.put(method, keys); 
    } 
    writeObject(methodKeys, keyFileName); 
    String fileName = key + ".pro"; 
    CacheRule cacheRule = new CacheRule(expireTime, object); 
    LogModel.log(" put " + method + " " + key + " " + cacheRule); 
    writeObject(cacheRule, fileName); 
  } 
 
  public static Object get(String method, HashMap params) { 
    long expireTime = CacheConfig.getExpireTime(method); 
    if (expireTime <= 0 || methodKeys == null || !methodKeys.containsKey(method)) {//有效时间小于0，则不需要缓存 
      return null; 
    } 
    ArrayList keys = methodKeys.get(method); 
//    String saveKey = keys.get(method); 
    String key = createKey(method, params); 
    String fileName = key + ".pro"; 
//    LogModel.log("get"+method+" "+(saveKey.equals(key))+" path:"+fileName); 
 
    CacheRule cacheRule = null; 
    try { 
      if (keys.contains(key)) { 
 cacheRule = (CacheRule) readObject(fileName); 
      } 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
    LogModel.log("get :" + method + " " + key + " " + cacheRule); 
    if (cacheRule != null && cacheRule.isExpire()) { 
      return cacheRule.getData(); 
    } else { 
      return null; 
    } 
  } 
 
 
  public static void main(String[] args) { 
    String method = "category.getCategory"; 
    HashMap params = new HashMap<>(); 
    params.put("categoryId", "-3"); 
    System.out.println(createKey(method, params)); 
    System.out.println(CacheRule.getCurrentTime()); 
  } 
 
   
  private static String createKey(String method, HashMap params) { 
    try { 
      MessageDigest digest = MessageDigest.getInstance("md5"); 
      digest.digest(method.getBytes("UTF-8")); 
      StringBuilder builder = new StringBuilder(method); 
      if (params != null && params.size() > 0) { 
 Iterator> iterator = params.entrySet().iterator(); 
 while (iterator.hasNext()) { 
   Map.Entry entry = iterator.next(); 
   builder.append(entry.getKey()).append("=").append(entry.getValue()); 
 } 
      } 
      byte[] tempArray = digest.digest(builder.toString().getBytes("UTF-8")); 
      StringBuffer keys = new StringBuffer(); 
      for (byte b : tempArray) { 
 // 与运算 
 int number = b & 0xff;// 加盐 
 String str = Integer.toHexString(number); 
 // System.out.println(str); 
 if (str.length() == 1) { 
   keys.append("0"); 
 } 
 keys.append(str); 
      } 
      return keys.toString().toUpperCase(); 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
    return method.toUpperCase(); 
  } 
 
   
  private static void writeObject(Object object, String fileName) { 
    try { 
      ObjectOutputStream oo = new ObjectOutputStream(new FileOutputStream(new File(CacheConfig.getCachePath() + fileName))); 
      oo.writeObject(object); 
      oo.close(); 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } 
  } 
 
   
  private static Object readObject(String fileName) { 
    Object result = null; 
    try { 
      File file = new File(CacheConfig.getCachePath() + fileName); 
      if (file.exists()) { 
 ObjectInputStream oi = new ObjectInputStream(new FileInputStream(file)); 
 result = oi.readObject(); 
 oi.close(); 
      } 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
    return result; 
  } 
}

CacheConfig---初始化哪些方法需要做缓存处理，以及缓存的有效时间

 
public final class CacheConfig { 
   
  private static HashMap methodExpireTimes = new HashMap(); 
  private static String cachePath = null; 
 
  static { 
    methodExpireTimes.put(ConstMethod.GET_CATEGORY_LIST,30 * 60 * 1000L); 
    methodExpireTimes.put(ConstMethod.GET_NEW_CATEGORY_LIST,30 * 60 * 1000L); 
  } 
 
   
  public static void init(Context context){ 
    cachePath = context.getFilesDir().getPath()+ File.separator+"cache"+File.separator; 
    File file = new File(cachePath); 
    if(!file.exists()){ 
      file.mkdirs(); 
    } 
    CacheManager.readCacheKey(); 
  } 
 
   
  public static String getCachePath() { 
    return cachePath; 
  } 
 
   
  public static long getExpireTime(String method){ 
    if(methodExpireTimes.containsKey(method)){ 
      return methodExpireTimes.get(method); 
    }else { 
      return -1; 
    } 
  } 
}

CacheRule---主要有两个参数，expireTime需要缓存的时间， data需要缓存的数据

public class CacheRule implements Serializable{ 
   
  public long expireTime; 
   
  public long cacheTime; 
   
  private Object data; 
 
  public CacheRule(long expireTime,Object data){ 
    cacheTime = getCurrentTime(); 
    this.expireTime = expireTime; 
    this.data = data; 
  } 
 
  public Object getData() { 
    return data; 
  } 
 
  public void setData(Object data) { 
    this.data = data; 
  } 
 
  @Override 
  public int hashCode() { 
    return BeanTools.createHashcode(expireTime, cacheTime, data); 
  } 
 
  @Override 
  public String toString() { 
    StringBuilder builder = new StringBuilder(); 
    builder.append("expireTime:").append(expireTime).append(" cacheTime:").append(cacheTime) 
 .append(" curTime:").append(getCurrentTime()) 
 .append(" isExpire:").append(isExpire()).append(" data:").append(data==null?"null":data.toString()); 
    return builder.toString(); 
  } 
 
   
  public boolean isExpire(){ 
    long curTime = getCurrentTime(); 
    return curTime>(expireTime+cacheTime)?false:true; 
  } 
 
   
  public static long getCurrentTime(){ 
//    if (Build.VERSION_CODES.JELLY_BEAN_MR1 <= Build.VERSION.SDK_INT) { 
//      return SystemClock.elapsedRealtimeNanos(); 
//    } else { 
      return System.currentTimeMillis(); 
//    } 
  } 
}

NetWorkManager---往RequestQueue中添加JacksonRequest请求，然后Volley会去请求数据

 
public final class NetWorkManager { 
 
 
  private RequestQueue requestQueue ; 
 
  public NetWorkManager(Context context){ 
    requestQueue = Volley.newRequestQueue(context); 
  } 
 
 
 
 
   
  public void jacksonRequest(final String url,final HashMap params,TypeReference javaType, ResponseListener listener, Response.ErrorListener errorListener){ 
    JacksonRequest jacksonRequest = new JacksonRequest(url,javaType,params,listener,errorListener); 
    requestQueue.add(jacksonRequest); 
  } 
 
   
  public void request(final String url,final HashMap params,Response.Listener listener,Response.ErrorListener errorListener){ 
 
    StringRequest stringRequest = new StringRequest(Request.Method.POST,url,listener,errorListener){ 
      @Override 
      protected Map getParams() throws AuthFailureError { 
 if (PrintLog.DEBUG) { 
   Iterator> iterator = params.entrySet().iterator(); 
   StringBuilder builder = new StringBuilder(url+" "); 
   while (iterator.hasNext()){ 
     Map.Entry entry = iterator.next(); 
     builder.append(entry.getKey()+":"+entry.getValue()).append("; "); 
   } 
   PrintLog.log(builder.toString()); 
 } 
 return params; 
      } 
    }; 
    requestQueue.add(stringRequest); 
  } 
 
 
}

JacksonRequest---继承Request，重写deliverResponse方法，并调用ResponseListener的onResponse方法，并通过CacheManager.put(methodName, params, response);将获取的response缓存到CacheManager中。这一步很重要，调用我们自己的listener，而不是Volley提供给我们的Response.Listener

 
public class JacksonRequest extends Request { 
  private final HashMap params; 
  private final ResponseListener listener; 
  private final ObjectMapper mapper; 
  private final TypeReference javaType; 
 
  public JacksonRequest(String url,TypeReference javaType,HashMap params,ResponseListener listener,Response.ErrorListener errorListener){ 
    super(Method.POST,url,errorListener); 
    mapper = new ObjectMapper(); 
    mapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES,true); 
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); 
    this.params = params; 
    this.listener = listener; 
    this.javaType = javaType; 
  } 
 
  @Override 
  protected Map getParams() throws AuthFailureError { 
    return params; 
  } 
 
  @Override 
  protected Response parseNetworkResponse(NetworkResponse response) { 
    String json; 
    try { 
      json = new String(response.data, HttpHeaderParser.parseCharset(response.headers)); 
      PrintLog.log("返回的json:" + json); 
      return Response.success(mapper.readValue(json,javaType), HttpHeaderParser.parseCacheHeaders(response)); 
    }catch (UnsupportedEncodingException e){ 
      json = new String(response.data); 
      PrintLog.log("json:"+json); 
      try { 
 return Response.success(mapper.readValue(json,javaType),HttpHeaderParser.parseCacheHeaders(response)); 
      } catch (IOException e1) { 
 return Response.error(new ParseError(e)); 
      } 
    } catch (JsonParseException e) { 
      PrintLog.log(e.toString()); 
      return Response.error(new ParseError(e)); 
    } catch (JsonMappingException e) {PrintLog.log(e.toString()); 
      return Response.error(new ParseError(e)); 
    } catch (IOException e) {PrintLog.log(e.toString()); 
      return Response.error(new ParseError(e)); 
    } 
  } 
 
  @Override 
  protected void deliverResponse(Object response) { 
    listener.onResponse(response,true); 
  } 
 
}

ResponseListener---自定义的一个listener接口，在发送请求时，需要将其实现。其中才参数中比Volley的提供的listener过了一个isCache的Boolean值，根据此值来决定是否要缓存。

 
public interface ResponseListener { 
  public void onResponse(T response, boolean isCache); 
}

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Android 中Volley二次封装并实现网络请求缓存

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