Android 中Volley二次封装并实现网络请求缓存

Nita ·

更新时间:2024-11-15

· 509 次阅读

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


/** 
 * @version V1.0 网络请求帮助类 
 * @author: mcoy 
 */ 
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; 
  /** 
   * 使用Jackson请求的方法 
   * @param methodName 
   * @param params 
   * @param handler 
   * @param msgId 
   */ 
  public void jacksonMethodRequest(final String methodName,final HashMap<String,String> 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<String,String> 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); 
  } 
  /** 
   * Url直接请求 
   * @param url 
   * @param params 
   * @param handler 
   * @param msgId 
   */ 
  public void urlRequest(String url,HashMap<String,String> params,JsonParser jsonParser,final Handler handler,final int msgId){ 
    request(url, true, params, jsonParser, handler, msgId); 
  } 
  /** 
   * 通过方法请求 
   * @param methodName 方法名 
   * @param params 请求参数 
   * @param jsonParser Json解析器 
   * @param handler 回调通知 
   * @param msgId 通知的Id 
   */ 
  public void methodRequest(String methodName, final HashMap<String,String> params,final JsonParser jsonParser,final Handler handler,final int msgId){ 
    request(getUrl(methodName),true,params,jsonParser,handler,msgId); 
  } 
  /** 
   * 通过方法请求 
   * @param methodName 方法名 
   * @param params 请求参数 
   * @param jsonParser Json解析器 
   * @param handler 回调通知 
   * @param msgId 通知的Id 
   */ 
  public void methodRequest(String methodName, boolean isLogin,final HashMap<String,String> 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<String,String> params,final JsonParser jsonParser,final Handler handler,final int msgId){ 
    final HashMap<String,String> allParams = Config.setSign(isLogin); 
    allParams.putAll(params); 
    Response.Listener listener = new Response.Listener<String>() { 
      @Override 
      public void onResponse(String response) { 
        /** 
         * 有些请求默认是没有parser传过来的，出参只求String，譬如联合登录等 
         * 所以加了一个else if 
         */ 
        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); 
  } 
  /** 
   * 根据访求名拼装请求的Url 
   * @param methodName 
   * @return 
   */ 
  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


/** 
 * @version V1.0 <缓存管理> 
 * @author: mcoy 
 */ 
public final class CacheManager { 
  /** 
   * 一个方法对应的多个Key，比如分类都是同一个方法，但是请求会不一样，可能都要缓存 
   */ 
  private static HashMap<String, ArrayList<String>> methodKeys; 
  private static final String keyFileName = "keys.pro"; 
  /** 
   * 读取缓存的Key 
   */ 
  public static void readCacheKey() { 
    methodKeys = (HashMap<String, ArrayList<String>>) readObject(keyFileName); 
    if (methodKeys == null) { 
      methodKeys = new HashMap<String, ArrayList<String>>(); 
    } 
  } 
  /** 
   * 保存缓存 
   */ 
  public static void put(String method, HashMap<String, String> 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<String> keys = methodKeys.get(method); 
      keys.add(key); 
    } else { 
      ArrayList<String> 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<String, String> 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<String> 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<String, String> params = new HashMap<>(); 
    params.put("categoryId", "-3"); 
    System.out.println(createKey(method, params)); 
    System.out.println(CacheRule.getCurrentTime()); 
  } 
  /** 
   * 生成Key 
   * 
   * @param method 请求的方法名 
   * @param params 私有参数(除公共参数以外的参数) 
   * @return 
   */ 
  private static String createKey(String method, HashMap<String, String> 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<Map.Entry<String, String>> iterator = params.entrySet().iterator(); 
        while (iterator.hasNext()) { 
          Map.Entry<String, String> 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(); 
  } 
  /** 
   * 将对象写到文件中 
   * 
   * @param object 
   * @param fileName 
   */ 
  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(); 
    } 
  } 
  /** 
   * 读取对象 
   * 
   * @param fileName 
   * @return 
   */ 
  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


/** 
 * @version V1.0 <设置哪些类数据需要缓存> 
 * @author: mcoy 
 */ 
public final class CacheConfig { 
  /**方法对应的缓存有效时间，时间是毫秒*/ 
  private static HashMap<String,Long> methodExpireTimes = new HashMap<String, Long>(); 
  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); 
  } 
  /** 
   * 初始化缓存路径 
   * @param context 
   */ 
  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(); 
  } 
  /**缓存路径*/ 
  public static String getCachePath() { 
    return cachePath; 
  } 
  /** 
   * 获取有方法对应的有效时间，如果方法没有添加缓存或者缓存时间小于0，则不添加缓存 
   * @param method 
   * @return 
   */ 
  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{ 
  /** 有效时间 */ 
  public long expireTime; 
  /** 缓存时间*/ 
  public long cacheTime; 
  /** 缓存数据 */ 
  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(); 
  } 
  /** 
   * 数据是否有效 
   * @return 
   */ 
  public boolean isExpire(){ 
    long curTime = getCurrentTime(); 
    return curTime>(expireTime+cacheTime)?false:true; 
  } 
  /** 
   * 获取当前时间 
   * @return 
   */ 
  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


/** 
 * 网络请求的工具类 
 */ 
public final class NetWorkManager { 
  private RequestQueue requestQueue ; 
  public NetWorkManager(Context context){ 
    requestQueue = Volley.newRequestQueue(context); 
  } 
  /** 
   * 使用Jackson解析请求的方法 
   * @param url 
   * @param params 
   * @param javaType 成功时返回的Java类型 
   * @param listener 
   * @param errorListener 
   */ 
  public void jacksonRequest(final String url,final HashMap<String,String> params,TypeReference javaType, ResponseListener listener, Response.ErrorListener errorListener){ 
    JacksonRequest jacksonRequest = new JacksonRequest(url,javaType,params,listener,errorListener); 
    requestQueue.add(jacksonRequest); 
  } 
  /** 
   * 普通的网络请求，返回的Json 
   * @param url 
   * @param params 
   * @param listener 
   * @param errorListener 
   */ 
  public void request(final String url,final HashMap<String,String> params,Response.Listener listener,Response.ErrorListener errorListener){ 
    StringRequest stringRequest = new StringRequest(Request.Method.POST,url,listener,errorListener){ 
      @Override 
      protected Map<String, String> getParams() throws AuthFailureError { 
        if (PrintLog.DEBUG) { 
          Iterator<Map.Entry<String,String>> iterator = params.entrySet().iterator(); 
          StringBuilder builder = new StringBuilder(url+" "); 
          while (iterator.hasNext()){ 
            Map.Entry<String,String> 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


/** 
 * Created by mcoy 
 */ 
public class JacksonRequest extends Request { 
  private final HashMap<String,String> params; 
  private final ResponseListener listener; 
  private final ObjectMapper mapper; 
  private final TypeReference javaType; 
  public JacksonRequest(String url,TypeReference javaType,HashMap<String,String> 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<String, String> 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。


/** 
 * @version V1.0 <描述当前版本功能> 
 * @author: mcoy 
 */ 
public interface ResponseListener<T> { 
  public void onResponse(T response, boolean isCache); 
}

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