实例：下载服务器zip资源（Json，Png，多种文件）
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一、前期基础知识储备
1）OKGO库地址：https://github.com/jeasonlzy/okhttp-OkGo
作者已停止维护，所以使用时需要在文档基础上，做必要的修改。
2）笔者用以下载服务器上一些简单的资源，比如Json，Png，这些资源都是打包成zip包的形式，尽量减小包体，便以传输。
3）由于是zip的形式传输，所以资源下载到本地之后，会有一个解压缩保存本地的过程，解压缩完毕得到对应资源后，需要删去zip包。
4）涉及到Json解析的时候，使用Gson库进行解析。
二、上代码，具体实现
1）引入依赖库；
def gsonVersion = "2.6.2"
def okgoVersion = "3.0.4"
implementation "com.google.code.gson:gson:$gsonVersion" // 解析Gson
implementation "com.lzy.net:okgo:$okgoVersion" // 下载资源
implementation "com.blankj:utilcode:1.25.9" // 万能工具库2）初始化OKGO；
public class ArtApp extends Application
@Override
public void onCreate()
super.onCreate();
if (isMainProcess())
OkHttpClient.Builder builder = new OkHttpClient.Builder();
//全局的读取超时时间
builder.readTimeout(30000L, TimeUnit.MILLISECONDS);
//全局的写入超时时间
builder.writeTimeout(30000L, TimeUnit.MILLISECONDS);
//全局的连接超时时间
builder.connectTimeout(100000L, TimeUnit.MILLISECONDS);
builder.proxy(Proxy.NO_PROXY);
builder.hostnameVerifier(new HostnameVerifier()
@Override
public boolean verify(String hostname, SSLSession session)
try
if (TextUtils.isEmpty(hostname) || TextUtils.isEmpty(session.getPeerHost()))
return false;
return hostname.equals(session.getPeerHost());
catch (Exception e)
return false;
);
OkGo.getInstance().init(this).setOkHttpClient(builder.build()).setRetryCount(3);
private String getCurrentProcessName()
int pid = android.os.Process.myPid();
String processName = "";
ActivityManager manager = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
for (ActivityManager.RunningAppProcessInfo process : manager.getRunningAppProcesses())
if (process.pid == pid)
processName = process.processName;
return processName;
public boolean isMainProcess()
return getApplicationContext().getPackageName().equals(getCurrentProcessName());
进入Android 29之后，OKGO需要补充一些声明，要不然会遇到一些 HostnameVerifier 错误；
3）Manifest文件中新增；
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<application
android:name=".ArtApp"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:requestLegacyExternalStorage="true"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme"
android:usesCleartextTraffic="true">
... ...
</application>①需要新增两项权限，后续需要了解网络状态，以做出不同的处理；
②处理不安全的网络访问，由于资源是放在“http”下，需要做下面处理，要不然访问不到；
android:requestLegacyExternalStorage="true"
android:usesCleartextTraffic="true"4）下载一份放置Png的zip包；
private static final String URL = "http://121.40.46.187/ts_paint_color/texture_001_png.zip";
private static final String FILENAME = "templatePng";
onDownLoadAndSavePNG(URL, "texture_001_png");
/*下载填充用的纹理图片*/
private void onDownLoadAndSavePNG(String pngUrl, final String fileName)
if (Utils.isNetWorkEnable(this))
OkGo.<File>get(pngUrl)
.execute(new FileCallback(this.getExternalFilesDir(FILENAME).getAbsolutePath()
+ File.separator, fileName + ".zip")
@Override
public void onSuccess(com.lzy.okgo.model.Response<File> response)
String zipFileName = getExternalFilesDir(FILENAME).getAbsolutePath()
+ File.separator + File.separator + fileName + ".zip";
String svgUnzipPath = ZipAndReadJsonUtils.unZipDownlaodSvgToSdCard(OkgoActivity.this, zipFileName);
txt.setText(svgUnzipPath);
File f = response.body();
if (f != null && f.exists())
Log.d(TAG, "onSuccess: file_Download success file exists 11,," + svgUnzipPath);
/*/storage/emulated/0/Android/data/camera.editor.art.paintsplash/files/templatePng/texture_001_png.zip*/
String jsonPath = getExternalFilesDir(FILENAME).getAbsolutePath() + File.separator + fileName;
Log.d(TAG, "onSuccess: file_Download success file exists 22,," + jsonPath);
/*/storage/emulated/0/Android/data/camera.editor.art.paintsplash/files/templatePng/texture_001_png*/
// 下载完毕删除zip包资源
File zipFile = response.body();
if (zipFile != null && zipFile.exists())
zipFile.delete();
@Override
public void onError(Response<File> response)
Log.d(TAG, "onError: file_Download file出错,," + response + ",," + response.body()
+ ",," + response.message() + ",," + response.getException() + ",," + response.isSuccessful());
@Override
public void downloadProgress(Progress progress)
);
else
/*没有联网 下载出错 解析出错 都要初始化本地数据*/
1）excute方法中，定义好下载后的资源存储处，下载成功监听中再处理；
2）onSuccess方法中，拿到下载好zip的资源存储处地址，然后调用解压缩的方法进行处理；
3）解压缩的方法中，输入参数为“需要解压缩文件所在地址”，输出的参数为“解压缩后得到的文件地址”；
解压缩方法如下：
public static String unZipDownlaodSvgToSdCard(Context context, String zipFileName)
String svgUnzipPath = "";
File zipFile = new File(zipFileName);
Log.d(TAG, "unZipDownlaodToSdCard: 需要解压缩文件所在地址," + zipFile.getAbsolutePath());
String fileName = "";
File saveJsonFile = context.getExternalFilesDir("templatePng");
if (saveJsonFile != null)
fileName = saveJsonFile.getAbsolutePath();
File file = new File(fileName);
try
ZipUtils.unzipFile(zipFile, file);
List<File> files = FileUtils.listFilesInDir(file);
svgUnzipPath = files.get(0).getAbsolutePath();
Log.d(TAG, "unZipDownlaodToSdCard: 解压缩后得到的文件地址，" + files.get(0).getAbsolutePath());
catch (IOException e)
Log.e(TAG, "unZipDownlaodSvgToSdCard: " + e.getMessage() );
e.printStackTrace();
return svgUnzipPath;
5）下载一份放置Json文件的zip包；
下载解压缩部分如上，此外多加一步处理——解析下载好的Json文件：
private JsonParser parser = new JsonParser();
private static final String CATEGORY = "artphoto";
private static final String CONTENT = "classic";
private static final String VERSION = "version";
/*下载Json文件*/
private void onDownLoadAndSaveJson(String svgUrl, String fileName)
if (Utils.isNetWorkEnable(getActivity()))
OkGo.<File>get(svgUrl)
.execute(new FileCallback(getActivity().getExternalFilesDir("templateJson").getAbsolutePath()
+ File.separator, fileName + ".zip")
@Override
public void onSuccess(com.lzy.okgo.model.Response<File> response)
String zipFileName = getActivity().getExternalFilesDir("templateJson").getAbsolutePath()
+ File.separator + File.separator + fileName + ".zip";
String svgUnzipPath = ZipAndReadJsonUtils.unZipDownlaodSvgToSdCard(getActivity(), zipFileName);
File f = response.body();
if (f != null && f.exists())
String jsonPath = getActivity().getExternalFilesDir("templateJson").getAbsolutePath() + File.separator + "templates.json";
String jsonText = Utils.jsonTransformFromFile(jsonPath);
JsonObject netRootObject = null;
List<StyleEntity> entities = LitePal.select("name").find(StyleEntity.class); /*只查询name这一列 其他字段为null*/
List<String> entitieNames = new ArrayList<>();
for (int i = 0; i < entities.size(); i++)
entitieNames.add(entities.get(i).getNmae());
try
netRootObject = (JsonObject) parser.parse(jsonText);
JsonObject netCategoryObject = netRootObject.getAsJsonObject(CATEGORY);
JsonArray netJsonArray = netCategoryObject.getAsJsonArray(CONTENT);
String netVersion = netCategoryObject.getAsJsonPrimitive(VERSION).getAsString();
String localVersion = PreferenceManager.getDefaultSharedPreferences(getActivity()).getString("localVer", "0.0");
if (!localVersion.equals(netVersion))
if (netJsonArray != null && netJsonArray.size() > 0)
PreferenceManager.getDefaultSharedPreferences(getActivity()).edit().putString("localVer", netVersion).apply();
for (int i = 0; i < netJsonArray.size(); i++)
JsonObject netObject = netJsonArray.get(i).getAsJsonObject();
String name = netObject.get("name").getAsString();
String index = netObject.get("index").getAsString();
String selected = netObject.get("selected").getAsString();
StyleEntity styleEntity = new StyleEntity(index, name, selected);
if (!entitieNames.contains(name))
styleEntity.save();
styleList.add(styleEntity);
initAdapter();
catch (JsonSyntaxException e)
Log.e(TAG, "onSuccess: 解析出错," + e.getMessage());
initAdapter();
@Override
public void onError(Response<File> response)
Log.d(TAG, "onError: file_Download file出错,," + response + ",," + response.body()
+ ",," + response.message() + ",," + response.getException() + ",," + response.isSuccessful());
initAdapter();
@Override
public void downloadProgress(Progress progress)
);
else
/*没有联网 下载出错 解析出错 都要初始化本地数据*/
initAdapter();
①拿到解析后的Json文件地址，然后读取该地址的Json文件，得到String类型的数据源；
/*将存储在本地Json文件读取出来*/
public static String jsonTransformFromFile(String filePath)
File file = new File(filePath);
StringBuilder stringBuilder = new StringBuilder();
try
FileInputStream fileInputStream = new FileInputStream(file);
BufferedReader bf = new BufferedReader(new InputStreamReader(fileInputStream));
String line;
while ((line = bf.readLine()) != null)
stringBuilder.append(line);
catch (FileNotFoundException e)
e.printStackTrace();
catch (IOException e)
e.printStackTrace();
return stringBuilder.toString();
② 利用Gson库，将Json数据源按照字段，解析为一个个对象；
/**
* Json格式为：
*
* "artphoto":
* "version": "1.0",
* "classic": [
*
* "name": "Forest Air",
* "index": "http://120.55.58.174/artphoto/style30.jpg",
* "selected": "false"
*
* ]
*
*
*/
JsonObject netRootObject = null;
netRootObject = (JsonObject) parser.parse(jsonText);
JsonObject netCategoryObject = netRootObject.getAsJsonObject(CATEGORY);
JsonArray netJsonArray = netCategoryObject.getAsJsonArray(CONTENT);
String netVersion = netCategoryObject.getAsJsonPrimitive(VERSION).getAsString();
if (netJsonArray != null && netJsonArray.size() > 0)
for (int i = 0; i < netJsonArray.size(); i++)
JsonObject netObject = netJsonArray.get(i).getAsJsonObject();
String name = netObject.get("name").getAsString();
String index = netObject.get("index").getAsString();
String selected = netObject.get("selected").getAsString();
StyleEntity styleEntity = new StyleEntity(index, name, selected);
if (!entitieNames.contains(name))
styleEntity.save();
styleList.add(styleEntity);
补充一个判断网络状态的工具类方法：
public static boolean isNetWorkEnable(Context context)
if (context != null)
ConnectivityManager manager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo info = manager.getActiveNetworkInfo();
if (info != null)
return info.isAvailable();
else
return false;
return false;
6）添加混淆；
#okhttp
-dontwarn okhttp3.**
-keep class okhttp3.***;
#okio
-dontwarn okio.**
-keep class okio.***;
# gson
-keepattributes Signature
-keepattributes *Annotation*
-keep class sun.misc.Unsafe *;
结语：笔者OKGO用久了，顺手。不过现在有更高效的联网下载网络资源的方法，之后再更新。
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