編輯：關於Android編程
自述：在此以前，自己從來沒有寫過博客，今天是第一次寫，真心是有點小激動，正要下筆卻不知道應該從何說起，若是寫的不好，請各位見諒吧！關於網絡請求，我自認為自己是一個菜鳥，沒有任何經驗，之前做的項目都是別人封裝好，告訴我怎麼調用就好了。至於怎麼封裝邏輯的，真是一竅不通，可近來比較閒，就學習封裝了一下OkHttp 。
OkHttp分為同步和異步請求；請求方式常用的有 get和post兩種方式，封裝請求的大致步驟為：
1、首先 創建 一個mOkHttpClient = new OkHttpClient()對象；
2、構建Request請求對象（根據get和post不同的請求方式分別創建）；
3、如果是 post請求還需要 構建 請求參數 Params，RequestBody requestBody = buildFormData(params); builder.post(requestBody).build;；
4、進行網絡異步請求mOkHttpClient.newCall(request).enqueue(new Callback() {} ），如果是同步請求，則改為 Response response = mOkHttpClient.newCall(request).execute()進行 ；
具體實現就不細說了，直接上代碼如下：
public class OkHttpManager {
private static OkHttpManager mOkHttpManager;
private OkHttpClient mOkHttpClient;
private Gson mGson;
private Handler handler;
private OkHttpManager() {
mOkHttpClient = new OkHttpClient();
mOkHttpClient.newBuilder().connectTimeout(10, TimeUnit.SECONDS).readTimeout(10, TimeUnit.SECONDS)
.writeTimeout(10, TimeUnit.SECONDS);
mGson = new Gson();
handler = new Handler(Looper.getMainLooper());
}
//創建 單例模式（OkHttp官方建議如此操作）
public static OkHttpManager getInstance() {
if (mOkHttpManager == null) {
mOkHttpManager = new OkHttpManager();
}
return mOkHttpManager;
}
/***********************
* 對外公布的可調方法
************************/
public void getRequest(String url, final BaseCallBack callBack) {
Request request = buildRequest(url, null, HttpMethodType.GET);
doRequest(request, callBack);
}
public void postRequest(String url, final BaseCallBack callBack, Map params) {
Request request = buildRequest(url, params, HttpMethodType.POST);
doRequest(request, callBack);
}
public void postUploadSingleImage(String url, final BaseCallBack callback, File file, String fileKey, Map params) {
Param[] paramsArr = fromMapToParams(params);
try {
postAsyn(url, callback, file, fileKey, paramsArr);
} catch (IOException e) {
e.printStackTrace();
}
}
public void postUploadMoreImages(String url, final BaseCallBack callback, File[] files, String[] fileKeys, Map params) {
Param[] paramsArr = fromMapToParams(params);
try {
postAsyn(url, callback, files, fileKeys, paramsArr);
} catch (IOException e) {
e.printStackTrace();
}
}
/***********************
* 對內方法
************************/
//單個文件上傳請求 不帶參數
private void postAsyn(String url, BaseCallBack callback, File file, String fileKey) throws IOException {
Request request = buildMultipartFormRequest(url, new File[]{file}, new String[]{fileKey}, null);
doRequest(request, callback);
}
//單個文件上傳請求 帶參數
private void postAsyn(String url, BaseCallBack callback, File file, String fileKey, Param... params) throws IOException {
Request request = buildMultipartFormRequest(url, new File[]{file}, new String[]{fileKey}, params);
doRequest(request, callback);
}
//多個文件上傳請求 帶參數
private void postAsyn(String url, BaseCallBack callback, File[] files, String[] fileKeys, Param... params) throws IOException {
Request request = buildMultipartFormRequest(url, files, fileKeys, params);
doRequest(request, callback);
}
//異步下載文件
public void asynDownloadFile(final String url, final String destFileDir, final BaseCallBack callBack) {
final Request request = buildRequest(url, null, HttpMethodType.GET);
callBack.OnRequestBefore(request); //提示加載框
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
callBack.onFailure(call, e);
}
@Override
public void onResponse(Call call, Response response) throws IOException {
// callBack.onResponse(response);
InputStream is = null;
byte[] buf = new byte[1024*2];
final long fileLength = response.body().contentLength();
int len = 0;
long readLength = 0;
FileOutputStream fos = null;
try {
is = response.body().byteStream();
File file = new File(destFileDir, getFileName(url));
fos = new FileOutputStream(file);
while ((len = is.read(buf)) != -1) {
fos.write(buf, 0, len);
readLength += len;
int curProgress = (int) (((float) readLength / fileLength) * 100);
Log.e("lgz", "onResponse: >>>>>>>>>>>>>" + curProgress + ", readLength = " + readLength + ", fileLength = " + fileLength);
callBack.inProgress(curProgress, fileLength, 0);
}
fos.flush();
//如果下載文件成功，第一個參數為文件的絕對路徑
callBackSuccess(callBack, call, response, file.getAbsolutePath());
} catch (IOException e) {
callBackError(callBack, call, response.code());
} finally {
try {
if (is != null)
is.close();
} catch (IOException e) {
}
try {
if (fos != null)
fos.close();
} catch (IOException e) {
}
}
}
});
}
//構造上傳圖片 Request
private Request buildMultipartFormRequest(String url, File[] files, String[] fileKeys, Param[] params) {
params = validateParam(params);
MultipartBody.Builder builder = new MultipartBody.Builder().setType(MultipartBody.FORM);
for (Param param : params) {
builder.addPart(Headers.of("Content-Disposition", "form-data; name=\"" + param.key + "\""),
RequestBody.create(MediaType.parse("image/png"), param.value));
}
if (files != null) {
RequestBody fileBody = null;
for (int i = 0; i < files.length; i++) {
File file = files[i];
String fileName = file.getName();
fileBody = RequestBody.create(MediaType.parse(guessMimeType(fileName)), file);
//TODO 根據文件名設置contentType
builder.addPart(Headers.of("Content-Disposition",
"form-data; name=\"" + fileKeys[i] + "\"; filename=\"" + fileName + "\""),
fileBody);
}
}
RequestBody requestBody = builder.build();
return new Request.Builder()
.url(url)
.post(requestBody)
.build();
}
//Activity頁面所有的請求以Activity對象作為tag，可以在onDestory()裡面統一取消,this
public void cancelTag(Object tag) {
for (Call call : mOkHttpClient.dispatcher().queuedCalls()) {
if (tag.equals(call.request().tag())) {
call.cancel();
}
}
for (Call call : mOkHttpClient.dispatcher().runningCalls()) {
if (tag.equals(call.request().tag())) {
call.cancel();
}
}
}
private String guessMimeType(String path) {
FileNameMap fileNameMap = URLConnection.getFileNameMap();
String contentTypeFor = fileNameMap.getContentTypeFor(path);
if (contentTypeFor == null) {
contentTypeFor = "application/octet-stream";
}
return contentTypeFor;
}
private String getFileName(String path) {
int separatorIndex = path.lastIndexOf("/");
return (separatorIndex < 0) ? path : path.substring(separatorIndex + 1, path.length());
}
private Param[] fromMapToParams(Map params) {
if (params == null)
return new Param[0];
int size = params.size();
Param[] res = new Param[size];
Set> entries = params.entrySet();
int i = 0;
for (Map.Entry entry : entries) {
res[i++] = new Param(entry.getKey(), entry.getValue());
}
return res;
}
//去進行網絡 異步 請求
private void doRequest(Request request, final BaseCallBack callBack) {
callBack.OnRequestBefore(request);
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
callBack.onFailure(call, e);
}
@Override
public void onResponse(Call call, Response response) throws IOException {
callBack.onResponse(response);
String result = response.body().string();
if (response.isSuccessful()) {
if (callBack.mType == String.class) {
// callBack.onSuccess(call, response, result);
callBackSuccess(callBack, call, response, result);
} else {
try {
Object object = mGson.fromJson(result, callBack.mType);//自動轉化為 泛型對象
// callBack.onSuccess(call, response, object);
callBackSuccess(callBack, call, response, object);
} catch (JsonParseException e) {
//json解析錯誤時調用
callBack.onEror(call, response.code(), e);
}
}
} else {
callBack.onEror(call, response.code(), null);
}
}
});
}
//創建 Request對象
private Request buildRequest(String url, Map params, HttpMethodType methodType) {
Request.Builder builder = new Request.Builder();
builder.url(url);
if (methodType == HttpMethodType.GET) {
builder.get();
} else if (methodType == HttpMethodType.POST) {
RequestBody requestBody = buildFormData(params);
builder.post(requestBody);
}
return builder.build();
}
//構建請求所需的參數表單
private RequestBody buildFormData(Map params) {
FormBody.Builder builder = new FormBody.Builder();
builder.add("platform", "android");
builder.add("version", "1.0");
builder.add("key", "123456");
if (params != null) {
for (Map.Entry entry : params.entrySet()) {
builder.add(entry.getKey(), entry.getValue());
}
}
return builder.build();
}
private void callBackSuccess(final BaseCallBack callBack, final Call call, final Response response, final Object object) {
handler.post(new Runnable() {
@Override
public void run() {
callBack.onSuccess(call, response, object);
}
});
}
private void callBackError(final BaseCallBack callBack, final Call call, final int code) {
handler.post(new Runnable() {
@Override
public void run() {
callBack.onEror(call, code, null);
}
});
}
private Param[] validateParam(Param[] params) {
if (params == null)
return new Param[0];
else
return params;
}
public static class Param {
public Param() {
}
public Param(String key, String value) {
this.key = key;
this.value = value;
}
String key;
String value;
}
enum HttpMethodType {
GET, POST
}
}
其中的 BaseCallBack回調機制封裝如下：
public abstract class BaseCallBack{ public Type mType; static Type getSuperclassTypeParameter(Class subclass) { Type superclass = subclass.getGenericSuperclass(); if (superclass instanceof Class) { throw new RuntimeException("Missing type parameter."); } ParameterizedType parameterized = (ParameterizedType) superclass; return $Gson$Types.canonicalize(parameterized.getActualTypeArguments()[0]); } public BaseCallBack() { mType = getSuperclassTypeParameter(getClass()); } protected abstract void OnRequestBefore(Request request); protected abstract void onFailure(Call call, IOException e); protected abstract void onSuccess(Call call, Response response, T t); protected abstract void onResponse(Response response); protected abstract void onEror(Call call, int statusCode, Exception e); protected abstract void inProgress(int progress, long total , int id); }
上面這個類OkHttpManager 是我根據網絡上各家資源學習封裝好的，copy進代碼可以直接使用，並且根據okhttp3.0以後的版本，對之前的一下請求參數設置進行了最新的修改，具體如下：
1、設置請求超時參數；
okhttp3.0以前的版本是這樣設置的
new OkHttpClient();
mHttpClient.setConnectTimeout(10, TimeUnit.SECONDS);
mHttpClient.setReadTimeout(10,TimeUnit.SECONDS);
mHttpClient.setWriteTimeout(30,TimeUnit.SECONDS);
之後的版本是這樣設置的：
new OkHttpClient.Builder()
.readTimeout(READ_TIMEOUT,TimeUnit.SECONDS)//設置讀取超時時間
.writeTimeout(WRITE_TIMEOUT,TimeUnit.SECONDS)//設置寫的超時時間
.connectTimeout(CONNECT_TIMEOUT,TimeUnit.SECONDS)//設置連接超時時間
2、post方式請求時，構建表單對象參數；
okhttp3.0以前的版本是這樣構建的：new FormEncodingBuilder（）對象，然後向裡面add (key,value)參數；
之後的版本更改為：FormBody body = new FormBody.Builder()，.add(key, value)；即是FormEncodingBuilder已被FormBody取代；
至於BaseCallBack類，根據請求數據的功能的不同，還需要對此進行封裝，集成自己需要的方法實現；
一、進行一般的數據加載請求，可直接調用如下：
模擬用戶登錄：
