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億速云。
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