OkHttp学习（2）--异步下载图片、文件（拦截器重写Response方法实现下载进度获取）

2024-08-31 23:08
文章标签 实现 学习 方法 图片 重写 异步 拦截器 获取 下载 进度 okhttp response

本文主要是介绍OkHttp学习（2）--异步下载图片、文件（拦截器重写Response方法实现下载进度获取），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

OkHttp学习（1）–>>同步和异步(get、post键值对、post带map、请求头体封装json)

Volley学习链接—想了解Volley的可以看我这5篇

今天来了解下okHttp如何进行图片、文件下载的
首先在OkHttpManger弄一个单利模式，初始化一个OkHttpClient，然后放进去一个handler，线程更新ui使用

private Handler okHttpHandler;private OkHttpClient mOkHttpClient;private OkHttpManger(){this.mOkHttpClient = new OkHttpClient.Builder().connectTimeout(30, TimeUnit.SECONDS)//连接超时限制.writeTimeout(30, TimeUnit.SECONDS)//写入超时.readTimeout(30, TimeUnit.SECONDS)//读取超时.build();this.okHttpHandler = new Handler(Looper.getMainLooper());}public static final OkHttpManger getInstance(){return SingleFactory.manger;}private static final class SingleFactory{private static final OkHttpManger manger = new OkHttpManger();}

然后直接执行下载方法

 public void downloadAsync(final String url, final String destFileDir,final OKHttpUICallback.ProgressCallback downListener) throws IOException {File file = new File(destFileDir,getFileName(url));if(!file.exists()){file.createNewFile();}downloadAsync(url, file, downListener);}

参数1为图片的url，我们这里用了http://img.mukewang.com/55249cf30001ae8a06000338.jpg来测试，
参数2destFileDir这个是下载完毕保存到手机的目录地址，我们传入的参数如下：

Config.getDirFile("download").getAbsolutePath()

这里做了一些目录的设置

public static File getDirFile(String subFileName){if(isSDMounted()){return mkdirsFolder(getSDirAbsolutePath() + "/Seeker/" + subFileName);}return null;}public static boolean isSDMounted(){return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);}public static File mkdirsFolder(String path){File file = new File(path);if(!file.exists()){return file.mkdirs()?file:null;}return file;}public static String getSDirAbsolutePath(){return Environment.getExternalStorageDirectory().getAbsolutePath();}

就是在sd卡根目录下创建Seeker/download文件夹，下载的图片就存在download文件夹下
目录有了，下载完毕图片，我们需要起一个名字把：

 File file = new File(destFileDir,getFileName(url));if(!file.exists()){file.createNewFile();}
 private String getFileName(String url){int lastSeparaorIndex = url.lastIndexOf("/");return (lastSeparaorIndex < 0) ? url : url.substring(lastSeparaorIndex + 1, url.length());}

然后正式进入下载的代码

public void downloadAsync(final String url, final File downFile,final OKHttpUICallback.ProgressCallback downListener) throws IOException {OkHttpClient downLoadClient = mOkHttpClient.newBuilder().addInterceptor(new Interceptor() {@Overridepublic Response intercept(Chain chain) throws IOException {//拦截Response origin = chain.proceed(chain.request());//包装响应体return origin.newBuilder().body(new ProgressBody.ProgressResponseBody(origin.body(), downListener, okHttpHandler)).build();}}).build();final Request request = new Request.Builder().url(url).build();downLoadClient.newCall(request).enqueue(new OKHttpThreadCallback(okHttpHandler,downListener,true).setFile(downFile));}

我们来看下代码里面做了什么操作?我们首先想到的是弄一个接口把
OKHttpUICallback.ProgressCallback downListener接口有3个接口方法，意思很明显。

 public interface ProgressCallback{void onSuccess(Call call, Response response, String path);void onProgress(long byteReadOrWrite, long contentLength, boolean done);void onError(Call call, IOException e);}

okhttp实现了拦截器Interceptor，这个是什么意思呢？

Interceptors area powerful mechanism that can monitor, rewrite, and retry calls.
拦截器可以用来转换，重试，重写请求的机制。这是官方的定义。
一句话就是对请求、相应加上自己的代码，重写方法

OkHttpClient downLoadClient = mOkHttpClient.newBuilder().addInterceptor(new Interceptor() {@Overridepublic Response intercept(Chain chain) throws IOException {//拦截Response origin = chain.proceed(chain.request());//包装响应体return origin.newBuilder().body(new ProgressBody.ProgressResponseBody(origin.body(), downListener, okHttpHandler)).build();}}).build();

这里就是用到了拦截器，大概意思就是，对请求响应体，进行二次包装，比如请求图片、文件的进度问题
我们看下我们做了什么操作呢？

new ProgressBody.ProgressResponseBody(origin.body(), downListener, okHttpHandler)
  @Overridepublic BufferedSource source() {if(bufferedSource == null){bufferedSource = Okio.buffer(source(responseBody.source()));}return bufferedSource;}/*** 读取，回调进度接口* @return*/private Source source(Source source){return new ForwardingSource(source) {//读取当前获取的字节数long totalBytesRead = 0L;@Overridepublic long read(Buffer sink, long byteCount) throws IOException {final long byteRead =  super.read(sink, byteCount);if(mHandler != null && mListener != null){//增加当前读取的字节数，如果读取完成则返回-1totalBytesRead += byteRead != -1?byteRead:0;//回调，若是contentLength()不知道长度，则返回-1mHandler.post(new Runnable() {@Overridepublic void run() {mListener.onProgress(totalBytesRead, contentLength(), byteRead == -1);}});}return byteRead;}};}

mListener.onProgress(totalBytesRead, contentLength(), byteRead == -1);就是对请求进度的一个对外通讯，告诉ui界面可以做一些操作，比如进度条之类的

然后继续看那个下载的入口方法里面的

downLoadClient.newCall(request).enqueue(new OKHttpThreadCallback(okHttpHandler,downListener,true).setFile(downFile));

这里面做了什么操作呢？

 @Overridepublic void onFailure(final Call call, final IOException e) {if(UICallback != null && UIHandler != null){UIHandler.post(new Runnable() {@Overridepublic void run() {UICallback.onError(call,e);}});}}@Overridepublic void onResponse(Call call, Response response) throws IOException {if(isDownload){download(call,response);}else{postSuccess(call,response);}}

就是在请求相应里面，进行sd写入

private void download(Call call, Response response) throws IOException {if(downFile == null){throw new NullPointerException("downFile == null");}byte[] buffer = new byte[2048];InputStream is = response.body().byteStream();int len;FileOutputStream fos = new FileOutputStream(downFile);while ((len = is.read(buffer)) != -1){fos.write(buffer,0,len);}fos.flush();if(is != null){is.close();}if (fos != null){fos.close();}postSuccess(call,null);}

然后在主界面进行接口方法实现，去实现其他需要处理的

 UICallback.onSuccess(call, response,downFile == null?null:downFile.getAbsolutePath());

如下是下载过程的log

09-01 18:05:55.398 22636-22636/com.example.administrator.myapplication I/MainActivity: downloadAsync
09-01 18:05:55.826 22636-22636/com.example.administrator.myapplication I/MainActivity: byteReadOrWrite:798,contentLength:471776,done:false
................
...............
09-01 18:06:04.795 22636-22636/com.example.administrator.myapplication I/MainActivity: byteReadOrWrite:471776,contentLength:471776,done:true
09-01 18:06:04.797 22636-22636/com.example.administrator.myapplication I/MainActivity: path:/storage/emulated/0/Seeker/download/55249cf30001ae8a06000338.jpg

另外附下载截图一张：
这里写图片描述

//以下是代码堆积区//

MainActivity

package com.example.administrator.myapplication;import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;import java.io.IOException;import okhttp3.Call;
import okhttp3.Response;public class MainActivity extends AppCompatActivity implements View.OnClickListener {Button downloadAsync;ImageView imageView;String url = "http://img.mukewang.com/55249cf30001ae8a06000338.jpg";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);imageView = (ImageView) findViewById(R.id.imageView);downloadAsync = (Button) findViewById(R.id.downloadAsync);downloadAsync.setOnClickListener(this);}@Overridepublic void onClick(View v) {switch (v.getId()){case R.id.downloadAsync:Log.i("MainActivity","downloadAsync");//下载图片try {OkHttpManger.getInstance().downloadAsync(url, Config.getDirFile("download").getAbsolutePath(), new OKHttpUICallback.ProgressCallback() {@Overridepublic void onSuccess(Call call, Response response, String path) {Log.i("MainActivity","path:"+path);}@Overridepublic void onProgress(long byteReadOrWrite, long contentLength, boolean done) {Log.i("MainActivity","byteReadOrWrite:"+byteReadOrWrite+",contentLength:"+contentLength+",done:"+done);}@Overridepublic void onError(Call call, IOException e) {Log.i("MainActivity","onError");}});} catch (IOException e) {e.printStackTrace();}break;}}
}

OkHttpManger

package com.example.administrator.myapplication;import android.os.Handler;
import android.os.Looper;
import android.util.Log;import com.alibaba.fastjson.JSON;import java.io.File;
import java.io.IOException;
import java.net.FileNameMap;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.FormBody;
import okhttp3.Headers;
import okhttp3.Interceptor;
import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;/*** OkHttp 工具类，* get的同步异步请求* post的json字符串同步异步上传* post的键值对同步异步上传* post文件异步上传，回调结果以及进度* 异步下载文件，回调结果以及进度** Created by Seeker on 2016/6/24.*/
public final class OkHttpManger {private static final String TAG = "OkHttpManger";private static final MediaType JSON_TYPE = MediaType.parse("application/json; charset=utf-8");private Handler okHttpHandler;private OkHttpClient mOkHttpClient;private OkHttpManger(){this.mOkHttpClient = new OkHttpClient.Builder().connectTimeout(30, TimeUnit.SECONDS)//连接超时限制.writeTimeout(30, TimeUnit.SECONDS)//写入超时.readTimeout(30, TimeUnit.SECONDS)//读取超时.build();this.okHttpHandler = new Handler(Looper.getMainLooper());}public static final OkHttpManger getInstance(){return SingleFactory.manger;}private static final class SingleFactory{private static final OkHttpManger manger = new OkHttpManger();}/*** 异步下载文件,实现了下载进度的提示** @param url* @param destFileDir 文件存储根路径* @param downListener*/public void downloadAsync(final String url, final String destFileDir,final OKHttpUICallback.ProgressCallback downListener) throws IOException {File file = new File(destFileDir,getFileName(url));if(!file.exists()){file.createNewFile();}downloadAsync(url, file, downListener);}/*** 获取文件名** @param path*/private String getFileName(String url){int lastSeparaorIndex = url.lastIndexOf("/");return (lastSeparaorIndex < 0) ? url : url.substring(lastSeparaorIndex + 1, url.length());}/*** 异步下载文件,实现了下载进度的提示* @param url* @param downFile:存储文件(文件存储绝对路径文件)* @param downListener* @throws IOException*/public void downloadAsync(final String url, final File downFile,final OKHttpUICallback.ProgressCallback downListener) throws IOException {OkHttpClient downLoadClient = mOkHttpClient.newBuilder().addInterceptor(new Interceptor() {@Overridepublic Response intercept(Chain chain) throws IOException {//拦截Response origin = chain.proceed(chain.request());//包装响应体return origin.newBuilder().body(new ProgressBody.ProgressResponseBody(origin.body(), downListener, okHttpHandler)).build();}}).build();final Request request = new Request.Builder().url(url).build();downLoadClient.newCall(request).enqueue(new OKHttpThreadCallback(okHttpHandler,downListener,true).setFile(downFile));}}

ProgressBody

package com.example.administrator.myapplication;import android.os.Handler;
import java.io.IOException;
import okhttp3.MediaType;
import okhttp3.RequestBody;
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;/*** Created by Safly on 2016/9/1.*/
public final class ProgressBody {/*** 包装响应体，用于处理提示下载进度** Created by Seeker on 2016/6/29.*/public static final class ProgressResponseBody extends ResponseBody {//实际待包装的响应体private final ResponseBody responseBody;//进度回调接口private OKHttpUICallback.ProgressCallback mListener;//包装完成的BufferedSourceprivate BufferedSource bufferedSource;//传递下载进度到主线程private Handler mHandler;public ProgressResponseBody(ResponseBody responseBody, OKHttpUICallback.ProgressCallback listener, Handler handler){this.responseBody = responseBody;this.mListener = listener;this.mHandler = handler;}@Overridepublic MediaType contentType() {return responseBody.contentType();}@Overridepublic long contentLength() {return responseBody.contentLength();}@Overridepublic BufferedSource source() {if(bufferedSource == null){bufferedSource = Okio.buffer(source(responseBody.source()));}return bufferedSource;}/*** 读取，回调进度接口* @return*/private Source source(Source source){return new ForwardingSource(source) {//读取当前获取的字节数long totalBytesRead = 0L;@Overridepublic long read(Buffer sink, long byteCount) throws IOException {final long byteRead =  super.read(sink, byteCount);if(mHandler != null && mListener != null){//增加当前读取的字节数，如果读取完成则返回-1totalBytesRead += byteRead != -1?byteRead:0;//回调，若是contentLength()不知道长度，则返回-1mHandler.post(new Runnable() {@Overridepublic void run() {mListener.onProgress(totalBytesRead, contentLength(), byteRead == -1);}});}return byteRead;}};}}}

OKHttpThreadCallback

package com.example.administrator.myapplication;import android.os.Handler;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Response;public final class OKHttpThreadCallback implements Callback {private Handler UIHandler;private OKHttpUICallback.ProgressCallback UICallback;private boolean isDownload;private File downFile;public OKHttpThreadCallback(Handler handler, OKHttpUICallback.ProgressCallback callback, boolean isDownload){this.UIHandler = handler;this.UICallback = callback;this.isDownload = isDownload;}@Overridepublic void onFailure(final Call call, final IOException e) {if(UICallback != null && UIHandler != null){UIHandler.post(new Runnable() {@Overridepublic void run() {UICallback.onError(call,e);}});}}@Overridepublic void onResponse(Call call, Response response) throws IOException {if(isDownload){download(call,response);}else{postSuccess(call,response);}}/*** 设置保存file* @param file*/public OKHttpThreadCallback setFile(File file){this.downFile = file;return this;}/*** 获取下载数据并写入文件* @param response*/private void download(Call call, Response response) throws IOException {if(downFile == null){throw new NullPointerException("downFile == null");}byte[] buffer = new byte[2048];InputStream is = response.body().byteStream();int len;FileOutputStream fos = new FileOutputStream(downFile);while ((len = is.read(buffer)) != -1){fos.write(buffer,0,len);}fos.flush();if(is != null){is.close();}if (fos != null){fos.close();}postSuccess(call,null);}/*** 回调成功信息* @param call* @param response*/private void postSuccess(final Call call, final Response response){if(UICallback != null && UIHandler != null){UIHandler.post(new Runnable() {@Overridepublic void run() {UICallback.onSuccess(call, response,downFile == null?null:downFile.getAbsolutePath());}});}}
}

Config

package com.example.administrator.myapplication;import android.os.Environment;import java.io.File;public class Config {public static File getDirFile(String subFileName){if(isSDMounted()){return mkdirsFolder(getSDirAbsolutePath() + "/Seeker/" + subFileName);}return null;}public static boolean isSDMounted(){return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);}public static File mkdirsFolder(String path){File file = new File(path);if(!file.exists()){return file.mkdirs()?file:null;}return file;}public static String getSDirAbsolutePath(){return Environment.getExternalStorageDirectory().getAbsolutePath();}}

最后看一个接口

package com.example.administrator.myapplication;import java.io.IOException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;import okhttp3.Call;
import okhttp3.Response;/*** Created by safly on 2016/9/1.* 回调主线程的接口*/
public class OKHttpUICallback {/*** 带有进度的上传、下载回调接口*/public interface ProgressCallback{void onSuccess(Call call, Response response, String path);void onProgress(long byteReadOrWrite, long contentLength, boolean done);void onError(Call call, IOException e);}
}

这篇关于OkHttp学习（2）--异步下载图片、文件（拦截器重写Response方法实现下载进度获取）的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！


http://www.chinasem.cn/article/1125252。

相关文章

Nginx安全防护的多种方法

Nginx安全防护的多种方法

《Nginx安全防护的多种方法》在生产环境中,需要隐藏Nginx的版本号,以避免泄漏Nginx的版本,使攻击者不能针对特定版本进行攻击,下面就来介绍一下Nginx安全防护的方法,感兴趣的可以了解一下... 目录核心安全配置1.编译安装 Nginx2.隐藏版本号3.限制危险请求方法4.请求限制（CC攻击防御）
阅读更多...
python生成随机唯一id的几种实现方法

python生成随机唯一id的几种实现方法

《python生成随机唯一id的几种实现方法》在Python中生成随机唯一ID有多种方法,根据不同的需求场景可以选择最适合的方案,文中通过示例代码介绍的非常详细,需要的朋友们下面随着小编来一起学习学习... 目录方法 1：使用 UUID 模块（推荐）方法 2：使用 Secrets 模块（安全敏感场景）方法
阅读更多...
一文详解如何使用Java获取PDF页面信息

一文详解如何使用Java获取PDF页面信息

《一文详解如何使用Java获取PDF页面信息》了解PDF页面属性是我们在处理文档、内容提取、打印设置或页面重组等任务时不可或缺的一环,下面我们就来看看如何使用Java语言获取这些信息吧... 目录引言一、安装和引入PDF处理库引入依赖二、获取 PDF 页数三、获取页面尺寸（宽高）四、获取页面旋转角度五、判断
阅读更多...
MyBatis-Plus通用中等、大量数据分批查询和处理方法

MyBatis-Plus通用中等、大量数据分批查询和处理方法

《MyBatis-Plus通用中等、大量数据分批查询和处理方法》文章介绍MyBatis-Plus分页查询处理,通过函数式接口与Lambda表达式实现通用逻辑,方法抽象但功能强大,建议扩展分批处理及流式... 目录函数式接口获取分页数据接口数据处理接口通用逻辑工具类使用方法简单查询自定义查询方法总结函数式接口
阅读更多...
MySQL深分页进行性能优化的常见方法

MySQL深分页进行性能优化的常见方法

《MySQL深分页进行性能优化的常见方法》在Web应用中,分页查询是数据库操作中的常见需求,然而,在面对大型数据集时,深分页（deeppagination）却成为了性能优化的一个挑战,在本文中,我们将... 目录引言：深分页，真的只是“翻页慢”那么简单吗？一、背景介绍二、深分页的性能问题三、业务场景分析四、
阅读更多...
JAVA中安装多个JDK的方法

JAVA中安装多个JDK的方法

《JAVA中安装多个JDK的方法》文章介绍了在Windows系统上安装多个JDK版本的方法,包括下载、安装路径修改、环境变量配置（JAVA_HOME和Path）,并说明如何通过调整JAVA_HOME在... 首先去oracle官网下载好两个版本不同的jdk（需要登录Oracle账号，没有可以免费注册）下载完
阅读更多...
Spring StateMachine实现状态机使用示例详解

Spring StateMachine实现状态机使用示例详解

《SpringStateMachine实现状态机使用示例详解》本文介绍SpringStateMachine实现状态机的步骤,包括依赖导入、枚举定义、状态转移规则配置、上下文管理及服务调用示例,重点解... 目录什么是状态机使用示例什么是状态机状态机是计算机科学中的​​核心建模工具​​，用于描述对象在其生命
阅读更多...
Spring Boot 结合 WxJava 实现文章上传微信公众号草稿箱与群发

Spring Boot 结合 WxJava 实现文章上传微信公众号草稿箱与群发

《SpringBoot结合WxJava实现文章上传微信公众号草稿箱与群发》本文将详细介绍如何使用SpringBoot框架结合WxJava开发工具包,实现文章上传到微信公众号草稿箱以及群发功能,... 目录一、项目环境准备1.1 开发环境1.2 微信公众号准备二、Spring Boot 项目搭建2.1 创建
阅读更多...
IntelliJ IDEA2025创建SpringBoot项目的实现步骤

IntelliJ IDEA2025创建SpringBoot项目的实现步骤

《IntelliJIDEA2025创建SpringBoot项目的实现步骤》本文主要介绍了IntelliJIDEA2025创建SpringBoot项目的实现步骤,文中通过示例代码介绍的非常详细,对大家... 目录一、创建 Spring Boot 项目1. 新建项目2. 基础配置3. 选择依赖4. 生成项目5.
阅读更多...
SQL server数据库如何下载和安装

SQL server数据库如何下载和安装

《SQLserver数据库如何下载和安装》本文指导如何下载安装SQLServer2022评估版及SSMS工具,涵盖安装配置、连接字符串设置、C#连接数据库方法和安全注意事项,如混合验证、参数化查... 目录第一步：打开官网下载对应文件第二步：程序安装配置第三部：安装工具SQL Server Manageme
阅读更多...

Copyright China编程 23002807@qq.com

沪ICP备2023033072号-2