安卓网络编程学习——java原生网络编程 _编程

业无高卑志当坚，男儿有求安得闲？这篇文章主要讲述安卓网络编程学习——java原生网络编程相关的知识，希望能为你提供帮助。
写在前面
该博客紧接上篇博客:https://www.cnblogs.com/wushenjiang/p/12937531.html,继续学习post请求,带参数的post和get请求以及文件上传与下载
post请求
其实post请求的方式与get请求差不太多，我们还是先上代码：

public void postRequest(View v) { new Thread(new Runnable() { @Override public void run() { OutputStream outputStream = null; InputStream inputStream = null; try { URL url = new URL(BASE_URL + "/post/comment"); HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); httpURLConnection.setRequestMethod("POST"); httpURLConnection.setConnectTimeout(10000); httpURLConnection.setRequestProperty("Content-Type", "application/json; charset=UTF-8"); httpURLConnection.setRequestProperty("Accept-Language", "zh-CN,zh; q=0.9"); httpURLConnection.setRequestProperty("Accept", "application/json,text/plain,*/*"); CommentItem commentItem = new CommentItem("234134123", "我是评论内容...哈哈"); Gson gson = new Gson(); String jsonStr = gson.toJson(commentItem); byte[] bytes = jsonStr.getBytes("UTF-8"); Log.d(TAG, "bytes==> " + bytes.length); httpURLConnection.setRequestProperty("Content-Length", String.valueOf(bytes.length)); //连接 httpURLConnection.connect(); //把数据给到服务器 outputStream = httpURLConnection.getOutputStream(); outputStream.write(bytes); outputStream.flush(); //拿到结果 int responseCode = httpURLConnection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { inputStream = httpURLConnection.getInputStream(); BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); Log.d(TAG, "result ==> " + bufferedReader.readLine()); } } catch (Exception e) { e.printStackTrace(); } finally { if (outputStream != null) { try { outputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } } }).start(); }

可以看到，与get请求不同的一点就是我们需要添加一个内容，然后把数据写入到服务端，最后关闭所有的流。整体的流程和get基本一致。
带参数的post和get请求
这里其实很类似，我们直接写一个方法统一起来：

private void startRequest(final Map< String, String> params, final String method, final String api) { new Thread(new Runnable() { BufferedReader bufferedReader = null; @Override public void run() { StringBuilder sb = new StringBuilder("?"); try { //组装参数 if (params != null & & params.size() > 0) { Iterator< Map.Entry< String, String> > iterator = params.entrySet().iterator(); while (iterator.hasNext()) { Map.Entry< String, String> next = iterator.next(); sb.append(next.getKey()); sb.append("="); sb.append(next.getValue()); if (iterator.hasNext()) { sb.append("& "); } } Log.d(TAG, "sb result --> " + sb.toString()); } URL url; String paramsStr = sb.toString(); if (paramsStr != null & & paramsStr.length() > 0) { url = new URL(BASE_URL + api + paramsStr); } else { url = new URL(BASE_URL + api); } Log.d(TAG, "url ==> " + url.toString()); HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); httpURLConnection.setRequestMethod(method); httpURLConnection.setRequestProperty("Accept-Language", "zh-CN,zh; q=0.9"); httpURLConnection.setRequestProperty("Accept", "*/*"); httpURLConnection.connect(); int responseCode; responseCode = httpURLConnection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { InputStream inputStream = httpURLConnection.getInputStream(); bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); String json = bufferedReader.readLine(); Log.d(TAG, "result ==> " + json); }} catch (Exception e) { e.printStackTrace(); } finally { if (bufferedReader != null) { try { bufferedReader.close(); } catch (IOException e) { e.printStackTrace(); } } } } }).start(); }

可以看到，我们主要就是需要将url进行一个字符串拼接，我们使用StringBuilder来进行字符串拼接，要更为安全。具体的操作流程请见代码，不用多说了。
文件上传
我们要做文件上传，其实很简单。先来上代码:

public void postFiles(View v) { new Thread(new Runnable() { OutputStream outputStream = null; InputStream inputStream = null; @Override public void run() { try { File fileOne = new File("/storage/emulated/0/Download/shop-ad.png"); File fileTwo = new File("/storage/emulated/0/Download/rBsADV64HDWAI6i_AAhJfxL8eXE287.png"); File fileThree = new File("/storage/emulated/0/Download/rBsADV64ILeAfwQMAAdBpy-0H04021.png"); String fileKey = "files"; String fileType = "image/png"; String BOUNDARY = "--------------------------246140106706876087289187"; //String BOUNDARY = "----------------------------246140106706876087289187"; URL url = new URL(BASE_URL + "/files/upload"); HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); httpURLConnection.setRequestMethod("POST"); httpURLConnection.setConnectTimeout(10000); httpURLConnection.setRequestProperty("User-Agent", "android/" + Build.VERSION.SDK_INT); httpURLConnection.setRequestProperty("Accept", "*/*"); httpURLConnection.setRequestProperty("Cache-Control", "no-cache"); httpURLConnection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY); httpURLConnection.setRequestProperty("Connection", "keep-alive"); httpURLConnection.setDoOutput(true); httpURLConnection.setDoInput(true); //连接 httpURLConnection.connect(); outputStream = httpURLConnection.getOutputStream(); uploadFile(fileOne, fileKey, fileOne.getName(), fileType, BOUNDARY, outputStream, false); uploadFile(fileTwo, fileKey, fileTwo.getName(), fileType, BOUNDARY, outputStream, false); uploadFile(fileThree, fileKey, fileThree.getName(), fileType, BOUNDARY, outputStream, true); outputStream.flush(); //获取返回结果 int responseCode = httpURLConnection.getResponseCode(); Log.d(TAG, "responseCode ==> " + responseCode); if (responseCode == HttpURLConnection.HTTP_OK) { inputStream = httpURLConnection.getInputStream(); BufferedReader bf = new BufferedReader(new InputStreamReader(inputStream)); String result = bf.readLine(); Log.d(TAG, "result ==> " + result); }} catch (Exception e) { e.printStackTrace(); } finally { //if (bfi != null) { //try { //bfi.close(); //} catch (IOException e) { //e.printStackTrace(); //} //} if (outputStream != null) { try { outputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } }private void uploadFile(File file, String fileKey, String fileName, String fileType, String BOUNDARY, OutputStream outputStream, boolean isLast) throws IOException { //准备数据 StringBuilder headerSbInfo = new StringBuilder(); headerSbInfo.append("--"); headerSbInfo.append(BOUNDARY); headerSbInfo.append("\\r\\n"); headerSbInfo.append("Content-Disposition: form-data; name=\\"" + fileKey + "\\"; filename=\\"" + fileName + "\\""); headerSbInfo.append("\\r\\n"); headerSbInfo.append("Content-Type:" + fileType); headerSbInfo.append("\\r\\n"); headerSbInfo.append("\\r\\n"); byte[] headerInfoBytes = headerSbInfo.toString().getBytes("UTF-8"); outputStream.write(headerInfoBytes); //文件内容 FileInputStream fos = new FileInputStream(file); BufferedInputStream bfi = new BufferedInputStream(fos); byte[] buffer = new byte[1024]; int len; while ((len = bfi.read(buffer, 0, buffer.length)) != -1) { outputStream.write(buffer, 0, len); } //写尾部信息 StringBuilder footerSbInfo = new StringBuilder(); footerSbInfo.append("\\r\\n"); footerSbInfo.append("--"); footerSbInfo.append(BOUNDARY); if (isLast) { footerSbInfo.append("--"); footerSbInfo.append("\\r\\n"); } footerSbInfo.append("\\r\\n"); outputStream.write(footerSbInfo.toString().getBytes("UTF-8")); } }).start(); }

仔细看，其实有点复杂。这里解释一下：
首先我们要先设置把本地的一张图设置为File类，而后设置连接的参数。之后是上传的方法可以看到，我们上传文件的方法也是一个字符串拼接，不过拼接的是一种固定格式，我们需要按照规定的格式拼接好才能让我们的服务器识别并上传。之后将图片转换成二进制文件进行读取，之后再拼接尾部格式。之后便是返回结果了。我们通过返回结果来看看是否上传成功，之后在自己的文件夹下看看是否有文件即可。
文件下载
和上传文件相比，下载文件就没有那么复杂了，如下代码:

public void downloadFile(View v) { new Thread(new Runnable() { FileOutputStream fileOutputStream = null; InputStream inputStream = null; @Override public void run() { try { URL url = new URL(BASE_URL + "/download/10"); HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); httpURLConnection.setConnectTimeout(10000); httpURLConnection.setRequestMethod("GET"); httpURLConnection.setRequestProperty("Accept-Language", "zh-CN,zh; q=0.9"); httpURLConnection.setRequestProperty("Accept", "*/*"); httpURLConnection.connect(); int responseCode = httpURLConnection.getResponseCode(); Log.d(TAG,"responseCode ==> "+responseCode); if (responseCode == HttpURLConnection.HTTP_OK) { Map< String, List< String> > headerFields = httpURLConnection.getHeaderFields(); for (Map.Entry< String, List< String> > stringListEntry : headerFields.entrySet()) { Log.d(TAG,stringListEntry.getKey() +"==="+stringListEntry.getValue()); } String headerField = httpURLConnection.getHeaderField("Content-disposition"); Log.d(TAG,"headerField --> "+headerField); //int index = headerField.indexOf("filename="); //String fileName = headerField.substring(index + "filename=".length()); //Log.d(TAG,"fileName ==> "+fileName); String fileName = headerField.replace("attachment; filename=", ""); Log.d(TAG,"fileName ==> "+fileName); File picFile = RequestTestActivity.this.getExternalFilesDir(Environment.DIRECTORY_PICTURES); if (!picFile.exists()) { picFile.mkdirs(); } File file = new File(picFile+fileName); if(!file.exists()){ file.createNewFile(); }fileOutputStream = new FileOutputStream(file); inputStream = httpURLConnection.getInputStream(); byte[] buffer = new byte[1024]; int len; while((len = inputStream.read(buffer,0,buffer.length)) != -1){ fileOutputStream.write(buffer,0,len); } fileOutputStream.flush(); } } catch (Exception e) { e.printStackTrace(); }finally { if (inputStream != null) { IOUtils.ioClose(inputStream); } if (fileOutputStream != null) { IOUtils.ioClose(fileOutputStream); } } } }).start(); }

【安卓网络编程学习——java原生网络编程】我们从服务器请求回文件，然后获取路径，新建文件和路径，然后存储进去即可。
总结
使用java API的编程操作到这里就先告一段落了，可以看到通过原生API编程的不易啊，后面我们马上学习框架使用和线程管理，就更能体会到框架的好处了。