android/179507.html">okhttp是Android6.0推出的網絡框架。由于谷歌在Android6.0的之后，將HttpClient相關屬性取消掉，導致Volley框架不能正常使用。所以才有了今天的Okhttp。
Okhttp進行網絡訪問通常有兩種方式，一種是get請求，還有一種叫做post請求。
1、OKhttp的get請求
通常，我們使用get方式來請求一個網站，是依靠url地址的。Okhttp使用get方式來請求網站通常有如下的步驟：
A、創建OkhttpClient的變量，這個變量相當于是一個全局的執行者。主要的網絡操作是依靠它來進行的。
B、創建一個builder對象。
C、利用builder對象創建一個Request對象。
D、使用全局執行者來創建一個Call對象。
E、通過Call對象來進行網絡連接。
public void doGet(View view) { Request.Builder builder = new Request.Builder(); Request request = builder.get().url(urlString + "userName=pby&userPassword=123").build(); Call newCall = mOkHttpClient.newCall(request); //newCall.execute() newCall.enqueue(new Callback() { @Override public void onFailure(Request request, IOException e) { L.e("失敗了"); } @Override public void onResponse(Response response) throws IOException { String string = response.body().string(); L.e(string); } }); }2、Okhttp的Post請求
Post請求與get請求有些不一樣。get請求主要的功能是從服務器上獲取數據，而Post請求則是向服務器提交數據。
public void doPost(View view) { FormEncodingBuilder requestBodyBuilder = new FormEncodingBuilder(); RequestBody requestBody = requestBodyBuilder.add("userName", "pby").add("userPassword", "123").build(); Request.Builder builder = new Request.Builder(); Request request = builder.url(urlString).post(requestBody).build(); Call newCall = mOkHttpClient.newCall(request); executeCall(newCall); }3、服務器端接收客戶端傳過來的字符串
客戶端的代碼：
public void doPostString(View view) { RequestBody requestBody = RequestBody.create(MediaType.parse("text/plain;charset = utf-8"), "{name = pby, password = 1234}"); Request.Builder builder = new Request.Builder(); Request request = builder.url(urlString + "doPostString").post(requestBody).build(); Call newCall = mOkHttpClient.newCall(request); executeCall(newCall); }服務器端的代碼：
public String doPostString() throws IOException { HttpServletRequest request = ServletActionContext.getRequest(); ServletInputStream inputStream = request.getInputStream(); StringBuilder sb = new StringBuilder(); int len = 0; byte []buff = new byte[1024]; while((len = inputStream.read(buff)) != -1) { sb.append(new String(buff, 0, len)); } System.out.println(sb.toString()); return null; }服務器端如果要接收客戶端的數據，則需要接收request；如果服務器端想要給客戶端傳數據，則需要通過response來傳遞。
4、使用post方式進行文件的傳輸
客戶端的代碼
public void doPost(View view) { FormEncodingBuilder requestBodyBuilder = new FormEncodingBuilder(); RequestBody requestBody = requestBodyBuilder.add("userName", "pby").add("userPassword", "123").build(); Request.Builder builder = new Request.Builder(); Request request = builder.url(urlString + "login").post(requestBody).build(); Call newCall = mOkHttpClient.newCall(request); executeCall(newCall); }關于選擇文件的代碼--抄襲網絡上的代碼，并不是自己寫的
private void showFileChooser() { Intent intent = new Intent(Intent.ACTION_GET_CONTENT); intent.setType("*/*"); intent.addCategory(Intent.CATEGORY_OPENABLE); try { startActivityForResult( Intent.createChooser(intent, "Select a File to Upload"), 1); } catch (android.content.ActivityNotFoundException ex) { Toast.makeText(this, "Please install a File Manager.", Toast.LENGTH_SHORT).show(); } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case 1: if (resultCode == RESULT_OK) { // Get the Uri of the selected file Uri uri = data.getData(); String path = FileUtils.getPath(this, uri); if(path != null) { postFile(path); } } break; } super.onActivityResult(requestCode, resultCode, data); }在進行這個的操作的時候，一定要記住增加讀和寫的權限，否則會上傳失敗的。
服務器端的代碼
public String doPostFile() throws IOException { HttpServletRequest request = ServletActionContext.getRequest(); ServletInputStream inputStream = request.getInputStream(); String dir = ServletActionContext.getServletContext().getRealPath("files"); File file = new File(dir, "abc.jpg"); FileOutputStream fos = new FileOutputStream(file); int len = 0; byte [] buff = new byte[1024]; while((len = inputStream.read(buff)) != -1) { fos.write(buff, 0, len); } fos.flush(); fos.close(); return null; }上面顯示的files文件，在Tomcat的webapps下的工程名名文件下的fies文件夾（才開始是沒有這個文件夾的，需要手動自己創建）。
5.使用Post方式來上傳文件
客戶端代碼：
private void upLoadFile(String path) { File file = new File(path); if(!file.exists()) { return ; } MultipartBuilder multipartBuilder = new MultipartBuilder(); RequestBody requestBody = multipartBuilder.type(MultipartBuilder.FORM) .addFormDataPart("userName", "pby") .addFormDataPart("userPassword", "123") .addFormDataPart("mFile", file.getName(), RequestBody.create(MediaType.parse("application/octet-stream"), file)).build();// CountingRequestBody countingRequestBody = new CountingRequestBody(requestBody, new CountingRequestBody.MyListener() {// @Override// public void onRequestProgress(int byteWriteCount, int TotalCount) {// L.e(byteWriteCount + " / " + TotalCount);// }// }); Request.Builder builder = new Request.Builder(); //Request request = builder.url(urlString + "doUpLoadFile").post(countingRequestBody).build(); Request request = builder.url(urlString + "doUpLoadFile").post(requestBody).build(); Call newCall = mOkHttpClient.newCall(request); executeCall(newCall); }服務器端的代碼：
public String doUpLoadFile() { if(mFile == null) { System.out.println(mFileFileName+" is null.."); return null; } String dir = ServletActionContext.getServletContext().getRealPath("files"); File file = new File(dir, mFileFileName); try { FileUtils.copyFile(mFile, file); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; }在上傳文件的時候，有一個小細節都注意到：就是Tomcat服務器只允許上傳2m以下的文件。要想上傳大文件，就必須在struct文件中加一句：<constant name="struts.multipart.maxSize" value="1024000000"/>數字表示自定義大小的限制。
6.上傳文件時，進度的顯示問題
在寫代碼的時候我們知道，我們不能直接獲得上傳文件的進度。因為這些數據都是封裝在RequestBody里面的，要想使用只有通過回調接口來實現。
package com.example.android_okhttp;import com.squareup.okhttp.MediaType;import com.squareup.okhttp.RequestBody;import java.io.IOException;import okio.Buffer;import okio.BufferedSink;import okio.ForwardingSink;import okio.Okio;import okio.Sink;/** * Created by 前世訣別的一紙書 on 2017/3/5. */public class CountingRequestBody extends RequestBody { private RequestBody delegate = null; private MyListener mListener= null; private CountingSink mCountSink = null; public interface MyListener { void onRequestProgress(int byteWriteCount, int TotalCount); } public CountingRequestBody(RequestBody requestBody, MyListener listener) { delegate = requestBody; mListener = listener; } @Override public MediaType contentType() { return delegate.contentType(); } @Override public void writeTo(BufferedSink sink) throws IOException { mCountSink = new CountingSink(sink); BufferedSink bs = Okio.buffer(mCountSink); delegate.writeTo(bs); bs.flush(); } private class CountingSink extends ForwardingSink{ private int byteWriteCount = 0; public CountingSink(Sink delegate) { super(delegate); } @Override public void write(Buffer source, long byteCount) throws IOException { super.write(source, byteCount); byteWriteCount += byteCount; mListener.onRequestProgress(byteWriteCount, (int) contentLength()); } } @Override public long contentLength() throws IOException { return delegate.contentLength(); }}MultipartBuilder multipartBuilder = new MultipartBuilder(); RequestBody requestBody = multipartBuilder.type(MultipartBuilder.FORM) .addFormDataPart("userName", "pby") .addFormDataPart("userPassword", "123") .addFormDataPart("mFile", file.getName(), RequestBody.create(MediaType.parse("application/octet-stream"), file)).build(); CountingRequestBody countingRequestBody = new CountingRequestBody(requestBody, new CountingRequestBody.MyListener() { @Override public void onRequestProgress(int byteWriteCount, int TotalCount) { L.e(byteWriteCount + " / " + TotalCount); } }); Request.Builder builder = new Request.Builder(); Request request = builder.url(urlString + "doUpLoadFile").post(countingRequestBody).build(); //Request request = builder.url(urlString + "doUpLoadFile").post(requestBody).build(); Call newCall = mOkHttpClient.newCall(request);以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
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