本篇记录的是Android开发中OkHttp框架的使用。OkHttp是Java中用于网络请求的一个库,主页为:http://square.github.io/okhttp/, github地址为:https://github.com/square/okhttp
下面介绍OkHttp库的用法,本篇会给出OkHttp的使用demo,demo中包含了常用的get请求、post请求、文件的上传和下载,demo运行的效果如下图所示:
下面上代码一一说明:
要使用OkHttp,必须在项目中先导入OkHttp,在app模块的build.gradle文件中,加入下面的代码:
dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) testCompile 'junit:junit:4.12' compile 'com.android.support:appcompat-v7:23.1.1' compile 'com.squareup.okhttp3:okhttp:3.2.0' }
这样就将OkHttp导入到项目中了。
(1)GET请求
最简单的GET请求用法如下:
//简单的Get请求,不带参数 public void simpleGetClick(View view) { okHttpClient = new OkHttpClient(); Request request = new Request.Builder() .url("http://192.168.1.170:8088/okhttp/test_simple_get.php") .build(); okHttpClient.newCall(request).enqueue(callback); }
如果请求中要添加Header头和参数,可以用下面的方式:
//带参数的Get请求 public void addParamGetClick(View view) { okHttpClient = new OkHttpClient(); Request request = new Request.Builder() .addHeader("token", "asdlfjkasdljfaskdjfalsjkljalk") //请求头中加入参数 .url("http://192.168.1.170:8088/okhttp/test_param_get.php?username=zhangsan&phone=13888888888") //携带参数 .build(); okHttpClient.newCall(request).enqueue(callback); }
需要注意的是,上面的代码中,callback是请求后的回调接口,代码如下:
//请求后的回调接口 private Callback callback = new Callback() { @Override public void onFailure(Call call, IOException e) { setResult(e.getMessage(), false); } @Override public void onResponse(Call call, Response response) throws IOException { setResult(response.body().string(), true); } };
这个回调接口需要注意的是,onResponse和onFailure都不是在UI线程中执行的,所以如果我们要在onResponse或onFailure中进行UI相关的操作,需要在UI线程中进行。
(2)POST请求
比较简单的POST请求,用法如下:
//简单的带参数和Header的post请求 public void simplePostClick(View view) { okHttpClient = new OkHttpClient(); RequestBody requestBody = new FormBody.Builder() .add("username", "wangwu") .add("password", "hello12345") .add("gender", "female") .build(); Request request = new Request.Builder() .url("http://192.168.1.170:8088/okhttp/test_simple_post.php") .post(requestBody) .addHeader("token", "helloworldhelloworldhelloworld") .build(); okHttpClient.newCall(request).enqueue(callback); }
这里我们需要先构造一个RequestBody,然后把需要携带的参数放到RequestBody中,然后使用这个RequestBody构建一个Request请求,最后将这个请求放入队列中执行
如果我们的POST请求稍微复杂点,比如携带的参数既有文本类型的,又有文件类型的,那么可以用下面的方式来请求:
//带文本参数和文件参数的post请求 public void filePostClick(View view) { RequestBody fileBody = RequestBody.create(MediaType.parse("text/plain; charset=utf-8"), tempFile); RequestBody requestBody = new MultipartBody.Builder() .setType(MultipartBody.FORM) .addFormDataPart("username", "wangwu") .addFormDataPart("password", "hello12345") .addFormDataPart("gender", "female") .addFormDataPart("file", "info.txt", fileBody) .build(); Request request = new Request.Builder() .url("http://192.168.1.170:8088/okhttp/test_param_post.php") .post(requestBody) .addHeader("token", "helloworldhelloworldhelloworld") .build(); okHttpClient.newCall(request).enqueue(callback); }
上面的代码中,tempFile是一个文本文件,为了POST提交文件和一些其他的参数,我们使用MultipartBody来构建一个请求体,需要注意的是,因为POST的内容含有文件,所以我们必须为这个请求体设置setType(MultipartBody.FORM)
(3)文件的上传
文件上传并显示进度,这个代码稍微有些复杂,下面直接上代码:
package com.test.testokhttp; import android.os.Environment; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.ProgressBar; import android.widget.TextView; import android.widget.Toast; import java.io.File; import java.io.IOException; import java.util.concurrent.TimeUnit; import okhttp3.Call; import okhttp3.Callback; import okhttp3.Interceptor; import okhttp3.MediaType; import okhttp3.MultipartBody; import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.RequestBody; import okhttp3.Response; import okhttp3.ResponseBody; import okio.Buffer; import okio.BufferedSink; import okio.BufferedSource; import okio.ForwardingSink; import okio.ForwardingSource; import okio.Okio; import okio.Sink; import okio.Source; public class UploadActivity extends AppCompatActivity { private OkHttpClient okHttpClient; private TextView resultTextView; private ProgressBar progressBar; private File tempFile; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_upload); setTitle("上传文件并显示进度"); resultTextView = (TextView) findViewById(R.id.result_textview); progressBar = (ProgressBar) findViewById(R.id.progress_bar); progressBar.setMax(100); okHttpClient = new OkHttpClient.Builder() .readTimeout(30, TimeUnit.SECONDS) .connectTimeout(10, TimeUnit.SECONDS) .writeTimeout(60, TimeUnit.SECONDS) .build(); } //点击按钮开始上传文件 public void startUploadClick(View view) { tempFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "test.pdf"); RequestBody requestBody = new MultipartBody.Builder() .setType(MultipartBody.FORM) .addFormDataPart("file", "test.pdf", RequestBody.create(MediaType.parse("application/pdf; charset=utf-8"), tempFile)) .build(); ProgressRequestBody progressRequestBody = new ProgressRequestBody(requestBody, progressListener); Request request = new Request.Builder() .url("http://192.168.1.170:8088/okhttp/test_upload_file.php") .post(progressRequestBody) .build(); okHttpClient.newCall(request).enqueue(callback); } //通过实现进度回调接口中的方法,来显示进度 private ProgressListener progressListener = new ProgressListener() { @Override public void update(long bytesRead, long contentLength, boolean done) { int progress = (int) (100.0 * bytesRead / contentLength); progressBar.setProgress(progress); } }; //请求后的回调方法 private Callback callback = new Callback() { @Override public void onFailure(Call call, IOException e) { setResult(e.getMessage(), false); } @Override public void onResponse(Call call, Response response) throws IOException { setResult(response.body().string(), true); } }; //显示请求返回的结果 private void setResult(final String msg, final boolean success) { runOnUiThread(new Runnable() { @Override public void run() { if (success) { Toast.makeText(UploadActivity.this, "请求成功", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(UploadActivity.this, "请求失败", Toast.LENGTH_SHORT).show(); } resultTextView.setText(msg); } }); } //自定义的RequestBody,能够显示进度 public class ProgressRequestBody extends RequestBody { //实际的待包装请求体 private final RequestBody requestBody; //进度回调接口 private final ProgressListener progressListener; //包装完成的BufferedSink private BufferedSink bufferedSink; /** * 构造函数,赋值 * * @param requestBody 待包装的请求体 * @param progressListener 回调接口 */ public ProgressRequestBody(RequestBody requestBody, ProgressListener progressListener) { this.requestBody = requestBody; this.progressListener = progressListener; } /** * 重写调用实际的响应体的contentType * * @return MediaType */ @Override public MediaType contentType() { return requestBody.contentType(); } /** * 重写调用实际的响应体的contentLength * * @return contentLength * @throws IOException 异常 */ @Override public long contentLength() throws IOException { return requestBody.contentLength(); } /** * 重写进行写入 * * @param sink BufferedSink * @throws IOException 异常 */ @Override public void writeTo(BufferedSink sink) throws IOException { if (bufferedSink == null) { //包装 bufferedSink = Okio.buffer(sink(sink)); } //写入 requestBody.writeTo(bufferedSink); //必须调用flush,否则最后一部分数据可能不会被写入 bufferedSink.flush(); } /** * 写入,回调进度接口 * * @param sink Sink * @return Sink */ private Sink sink(Sink sink) { return new ForwardingSink(sink) { //当前写入字节数 long bytesWritten = 0L; //总字节长度,避免多次调用contentLength()方法 long contentLength = 0L; @Override public void write(Buffer source, long byteCount) throws IOException { super.write(source, byteCount); if (contentLength == 0) { //获得contentLength的值,后续不再调用 contentLength = contentLength(); } //增加当前写入的字节数 bytesWritten += byteCount; //回调 progressListener.update(bytesWritten, contentLength, bytesWritten == contentLength); } }; } } //进度回调接口 interface ProgressListener { void update(long bytesRead, long contentLength, boolean done); } }
上面需要注意的是,上传文件需要实现自定义的RequestBody,也就是上面的ProgressRequestBody,在ProgressRequestBody中获取上传的进度。
(4)文件的下载
下载和上传类似,区别在于,需要我们实习自定义的ResponseBody而不是RequestBody了,下面上代码:
import android.os.Environment; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.ProgressBar; import android.widget.TextView; import android.widget.Toast; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.concurrent.TimeUnit; import okhttp3.Call; import okhttp3.Callback; import okhttp3.Interceptor; import okhttp3.MediaType; import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.Response; import okhttp3.ResponseBody; import okio.Buffer; import okio.BufferedSource; import okio.ForwardingSource; import okio.Okio; import okio.Source; public class DownloadActivity extends AppCompatActivity { private OkHttpClient okHttpClient; private TextView resultTextView; private ProgressBar progressBar; private File tempFile; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_download); setTitle("下载文件并显示进度"); okHttpClient = new OkHttpClient.Builder() .addNetworkInterceptor(new Interceptor() { @Override public Response intercept(Interceptor.Chain chain) throws IOException { Response originalResponse = chain.proceed(chain.request()); return originalResponse.newBuilder() .body(new ProgressResponseBody(originalResponse.body(), progressListener)) .build(); } }) .connectTimeout(5, TimeUnit.SECONDS) .readTimeout(300, TimeUnit.SECONDS) .writeTimeout(30, TimeUnit.SECONDS) .build(); resultTextView = (TextView) findViewById(R.id.result_textview); progressBar = (ProgressBar) findViewById(R.id.progress_bar); tempFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + System.currentTimeMillis() + ".pdf"); } //下载文件 public void startDownloadClick(View view) { Request request = new Request.Builder() .url("http://192.168.1.170:8088/okhttp/test.pdf") .build(); okHttpClient.newCall(request).enqueue(callback); } private ProgressListener progressListener = new ProgressListener() { @Override public void update(long bytesRead, long contentLength, boolean done) { int progress = (int) (100.0 * bytesRead / contentLength); progressBar.setProgress(progress); } }; //请求后的回调方法 private Callback callback = new Callback() { @Override public void onFailure(Call call, IOException e) { setResult(e.getMessage(), false); } @Override public void onResponse(Call call, Response response) throws IOException { if(response != null) { //下载完成,保存数据到文件 InputStream is = response.body().byteStream(); FileOutputStream fos = new FileOutputStream(tempFile); byte[] buf = new byte[1024]; int hasRead = 0; while((hasRead = is.read(buf)) > 0) { fos.write(buf, 0, hasRead); } fos.close(); is.close(); setResult("下载成功", true); } } }; //显示请求返回的结果 private void setResult(final String msg, final boolean success) { runOnUiThread(new Runnable() { @Override public void run() { if (success) { Toast.makeText(DownloadActivity.this, "请求成功", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(DownloadActivity.this, "请求失败", Toast.LENGTH_SHORT).show(); } resultTextView.setText(msg); } }); } //自定义的ResponseBody,在其中处理进度 private static class ProgressResponseBody extends ResponseBody { private final ResponseBody responseBody; private final ProgressListener progressListener; private BufferedSource bufferedSource; public ProgressResponseBody(ResponseBody responseBody, ProgressListener progressListener) { this.responseBody = responseBody; this.progressListener = progressListener; } @Override public MediaType contentType() { return responseBody.contentType(); } @Override public long contentLength() { return responseBody.contentLength(); } @Override public BufferedSource source() { if (bufferedSource == null) { bufferedSource = Okio.buffer(source(responseBody.source())); } return bufferedSource; } private Source source(Source source) { return new ForwardingSource(source) { long totalBytesRead = 0L; @Override public long read(Buffer sink, long byteCount) throws IOException { long bytesRead = super.read(sink, byteCount); // read() returns the number of bytes read, or -1 if this source is exhausted. totalBytesRead += bytesRead != -1 ? bytesRead : 0; progressListener.update(totalBytesRead, responseBody.contentLength(), bytesRead == -1); return bytesRead; } }; } } //进度回调接口 interface ProgressListener { void update(long bytesRead, long contentLength, boolean done); } }
如果我们在项目中直接使用上面的代码来进行http请求的话,势必会比较麻烦,所以这里我们需要封装上面的代码,尽量在项目中能用简短的代码完成网络请求。另外,一个项目中肯定会有很多个网络请求,我们没必要在每次网络请求中都创建一个OkHttpClient对象,所有的请求公用一个OkHttpClient就可以了。
参考:http://blog.csdn.net/lmj623565791/article/details/47911083