网络框架-Volley

Volley概述:

Volley是Google 2013年I/O大会推出的针对Android的HTTP网络请求框架，让网络请求更简单，更快。

特点：

• 自动调度网络请求
• 支持并发网络连接
• 支持标准的HTTP缓存协议（由服务器来决定是否缓存数据）
• 支持请求优先级设置
• 支持取消单个或多个请求
• 易于定制，扩展性强。比如Retry&Backoff机制
• 强大的网络请求能力让你轻松的发送异步请求来填充UI数据
• 提供调试和跟踪工具
  优点:
  擅长将RPC(远程过程调用协议,C/S模式)类型的操作，用来展示服务器数据。比如以某种数据格式获取一页搜索结果。支持任意的数据传输格式，比如图片，字符串，json，你也可以定义自己的数据格式。其实就是自定义Request。Volley让你不再写这些重复的模板代码（网络请求逻辑，不再重复造轮子），这样你就可以专注于你应用本身的业务逻辑.
  缺点:
  由于Volley都是在内存中解析和处理数据，所以不适合大数据量的下载操作。如果需要下载大文件，可以考虑使用系统的DownloadManager

注意事项:

• 如果自己编译Volley的话,compileSdkVersion需要<=22,直接使用Volley框架
• 如果大于等于22，需要引入：useLibrary “org.apache.http.legacy”，集成httpClinet的Api(这是因为在Android6.0中Google移除了httpClient相关的API)
• Volley仅适合用于通信频繁数据量小的网络操作
• 大数据量的网络操作并不适合Volley

基本使用

发送get请求

//获取最新博客列表String url = "http://www.oschina.net/action/api/blog_list?pageIndex=0&pageSize=20&type=latest";//构建请求队列RequestQueue requestQueue = Volley.newRequestQueue(this);//构建请求对象Request<? extends Object> request = new StringRequest(url, new Response.Listener<String>() {@Overridepublic void onResponse(String response) {        Toast.makeText(GetActivity.this, "结果 = " + response, Toast.LENGTH_SHORT).show();    }}, new Response.ErrorListener() {@Overridepublic void onErrorResponse(VolleyError error) {        Toast.makeText(GetActivity.this, "错误 = " + error, Toast.LENGTH_SHORT).show();    }});//添加到请求队列中,并执行请求requestQueue.add(request);

发送post请求

String url = "http://www.oschina.net/action/api/login_validate";//封装请求参数final Map<String, String> params = new HashMap<>();params.put("keep_login", "1");params.put("username", "xxx.com");params.put("pwd", "xxx");//构建请求队列RequestQueue requestQueue = Volley.newRequestQueue(this);//构建请求对象,并重写request内部方法getParams,设置请求参数Request<? extends Object> request = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {@Overridepublic void onResponse(String response) {        Toast.makeText(PostActivity.this, "登录成功 = " + response, Toast.LENGTH_SHORT).show();    }}, new Response.ErrorListener() {@Overridepublic void onErrorResponse(VolleyError error) {        Toast.makeText(PostActivity.this, "登录失败 = ", Toast.LENGTH_SHORT).show();    }}) {@Overrideprotected Map<String, String> getParams() throws AuthFailureError {        return params;    }};//将请求对象添加到请求队列中,并执行请求requestQueue.add(request);

自定义请求对象(Request)

 /**     * 自定义Request     */    private class MyRequest extends Request<String>{        private Response.Listener<String>mListener;        private Map<String, String>params;        private Map<String, String>headers;        public MyRequest(int method, String url, Map<String, String>  params, Map<String, String> headers, Response.Listener<String> listener,                         Response.ErrorListener errorListener) {            super(method, url, errorListener);            mListener = listener;            this.params = params;            this.headers = headers;        }        //设置请求参数        @Override        protected Map<String, String> getParams() throws AuthFailureError {            if(params == null){                params = Collections.EMPTY_MAP;            }            return params;        }        //设置请求头信息        @Override        public Map<String, String> getHeaders() throws AuthFailureError {            if(headers == null){                headers = Collections.EMPTY_MAP;            }            return headers;        }        //处理响应结果        @Override        protected Response<String> parseNetworkResponse(NetworkResponse response) {            String parsed;            try {                parsed = new String(response.data, HttpHeaderParser.parseCharset(response.headers));            } catch (UnsupportedEncodingException e) {                parsed = new String(response.data);            }            return Response.success(parsed, HttpHeaderParser.parseCacheHeaders(response));        }        //将响应结果分发给客户端        @Override        protected void deliverResponse(String response) {            mListener.onResponse(response);        }    }

自定义请求列队

    DiskBasedCache diskBaseCache = new DiskBasedCache(getCacheDir(), 10 * 1024 * 1024);    BasicNetwork newtwork = new BasicNetwork(new HurlStack());    //自定义请求队列    RequestQueue  requestQueue = new RequestQueue(            diskBaseCache,//缓存工具, 将请求的响应结果,进行缓存            newtwork    );    //获取最新博客列表    String url = "http://www.oschina.net/action/api/blog_list?pageIndex=0&pageSize=20&type=latest";    Request<? extends Object> request = new StringRequest(url, new Response.Listener<String>() {        @Override        public void onResponse(String response) {            Toast.makeText(RequestQueueActivity.this, "结果 = " + response, Toast.LENGTH_SHORT).show();        }    }, new Response.ErrorListener() {        @Override        public void onErrorResponse(VolleyError error) {            Toast.makeText(RequestQueueActivity.this, "错误 = " + error, Toast.LENGTH_SHORT).show();        }    });//添加到请求队列中requestQueue.add(request);//执行请求requestQueue.start();

上传文件

  String url = "http://www.oschina.net/action/apiv2/resource_image";    RequestQueue requestQueue = Volley.newRequestQueue(this);    Map<String, Object> params = new HashMap<>();params.put("resource", new File(Environment.getExternalStorageDirectory().getPath() + "/bear.png"));    MultipartRequest multipartRequest = new MultipartRequest(            url,            null,            params,            new Response.Listener<String>(){                @Override                public void onResponse(String response) {                    Toast.makeText(PostActivity.this, "登录成功 = " + response, Toast.LENGTH_SHORT).show();                }            },            new Response.ErrorListener(){                @Override                public void onErrorResponse(VolleyError error) {                    Toast.makeText(PostActivity.this, "登录失败 = ", Toast.LENGTH_SHORT).show();                }            }    );requestQueue.add(multipartRequest);//这里需要自定义MultipartRequestpublic class MultipartRequest extends Request<String> {        private MultipartEntity entity;        private final Response.Listener<String>mListener;        private List<Part>partList = new ArrayList<Part>();        private Map<String, String>mHeaders;        public MultipartRequest(String url,                                Response.ErrorListener errorListener,//                                Response.Listener<String> listener,//                                Map<String, Object> params,//                                Map<String, String> headers        ) {            super(Method.POST, url, errorListener);            mHeaders = headers;            mListener = listener;            if (params != null && params.size() >0) {                for (Map.Entry<String, Object> entry : params.entrySet()) {                    String key = entry.getKey();                    Object o = entry.getValue();                    if (o instanceof File) {                        try {                            partList.add(new FilePart(key, (File) o));                        } catch (FileNotFoundException e) {                            e.printStackTrace();                        }                    } else {                        partList.add(new StringPart(key, (String) o));                    }                }            }            buildMultipartEntity();        }        private void buildMultipartEntity() {            try {                entity = new MultipartEntity(partList.toArray(new Part[partList.size()]));            } catch (Exception e) {                VolleyLog.e("UnsupportedEncodingException");            }        }        @Override        public String getBodyContentType() {            return entity.getContentType().getValue();        }        @Override        public byte[] getBody() throws AuthFailureError {            ByteArrayOutputStream bos = new ByteArrayOutputStream();            try {                entity.writeTo(bos);            } catch (IOException e) {                VolleyLog.e("IOException writing to ByteArrayOutputStream");            }            return bos.toByteArray();        }        @Override        protected Response<String> parseNetworkResponse(NetworkResponse response) {            String parsed;            try {                parsed = new String(response.data,                        HttpHeaderParser.parseCharset(response.headers));                ALog.d(parsed);            } catch (UnsupportedEncodingException e) {                parsed = new String(response.data);            }            return Response.success(parsed,                    HttpHeaderParser.parseCacheHeaders(response));        }        /*             * (non-Javadoc)             *             * @see com.android.volley.Request#getHeaders()             */        @Override        public Map<String, String> getHeaders() throws AuthFailureError {            if (mHeaders == null || mHeaders.equals(Collections.emptyMap())) {                mHeaders = new HashMap<String, String>();            }            return mHeaders;        }        @Override        protected void deliverResponse(String response) {            mListener.onResponse(response);        }

自我感觉好繁琐...