編輯:關於Android編程
OKHttp是一款高效的HTTP客戶端,支持連接同一地址的鏈接共享同一個socket,通過連接池來減小響應延遲,還有透明的GZIP壓縮,請求緩存等優勢。(GitHub頁:https://github.com/square/okhttp)
Android為我們提供了兩種HTTP交互的方式:HttpURLConnection 和 Apache HTTP Client,雖然兩者都支持HTTPS,流的上傳和下載,配置超時,IPv6和連接池,已足夠滿足我們各種HTTP請求的需求。但更高效的使用HTTP 可以讓您的應用運行更快、更節省流量。而OkHttp庫就是為此而生。
OkHttp是一個高效的HTTP庫:
如果您的服務器配置了多個IP地址,當第一個IP連接失敗的時候,OkHttp會自動嘗試下一個IP。OkHttp還處理了代理服務器問題和SSL握手失敗問題。
使用 OkHttp 無需重寫您程序中的網絡代碼。OkHttp實現了幾乎和java.net.HttpURLConnection一樣的API。如果您用了 Apache HttpClient,則OkHttp也提供了一個對應的okhttp-apache 模塊。
引入
可以通過下載jar包直接導入工程地址
或者通過構建的方式導入
MAVEN:
<dependency> <groupId>com.squareup.okhttp</groupId> <artifactId>okhttp</artifactId> <version>2.4.0</version> </dependency>
GRADLE:
compile 'com.squareup.okhttp:okhttp:2.4.0'用法
package com.jackchan.test.okhttptest; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.util.Log; import com.squareup.okhttp.Cache; import com.squareup.okhttp.Callback; import com.squareup.okhttp.OkHttpClient; import com.squareup.okhttp.Request; import com.squareup.okhttp.Response; import java.io.File; import java.io.IOException; public class TestActivity extends ActionBarActivity { private final static String TAG = "TestActivity"; private final OkHttpClient client = new OkHttpClient(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_test); new Thread(new Runnable() { @Override public void run() { try { execute(); } catch (Exception e) { e.printStackTrace(); } } }).start(); } public void execute() throws Exception { Request request = new Request.Builder() .url("http://publicobject.com/helloworld.txt") .build(); Response response = client.newCall(request).execute(); if(response.isSuccessful()){ System.out.println(response.code()); System.out.println(response.body().string()); } } }我們通過Request.Builder傳入url,然後直接execute執行得到Response,通過Response可以得到code,message等信息。
private void enqueue(){ Request request = new Request.Builder() .url("http://publicobject.com/helloworld.txt") .build(); client.newCall(request).enqueue(new Callback() { @Override public void onFailure(Request request, IOException e) { } @Override public void onResponse(Response response) throws IOException { //NOT UI Thread if(response.isSuccessful()){ System.out.println(response.code()); System.out.println(response.body().string()); } } }); }就是在同步的基礎上講execute改成enqueue,並且傳入回調接口,但接口回調回來的代碼是在非UI線程的,因此如果有更新UI的操作記得用Handler或者其他方式。
Request request = new Request.Builder() .url("https://api.github.com/repos/square/okhttp/issues") .header("User-Agent", "OkHttp Headers.java") .addHeader("Accept", "application/json; q=0.5") .addHeader("Accept", "application/vnd.github.v3+json") .build();傳入POST參數
RequestBody formBody = new FormEncodingBuilder() .add("platform", "android") .add("name", "bug") .add("subject", "XXXXXXXXXXXXXXX") .build(); Request request = new Request.Builder() .url(url) .post(body) .build();可以看出來,傳入header或者post參數都是傳到Request裡面,因此最後的調用方式也和GET方式一樣
Response response = client.newCall(request).execute(); if (response.isSuccessful()) { return response.body().string(); } else { throw new IOException("Unexpected code " + response); }這個代碼是同步網絡請求,異步就改成enqueue就行了。
package com.jackchan.test.okhttptest; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.util.Log; import com.squareup.okhttp.Cache; import com.squareup.okhttp.CacheControl; import com.squareup.okhttp.Call; import com.squareup.okhttp.Callback; import com.squareup.okhttp.OkHttpClient; import com.squareup.okhttp.Request; import com.squareup.okhttp.Response; import java.io.File; import java.io.IOException; public class TestActivity extends ActionBarActivity { private final static String TAG = "TestActivity"; private final OkHttpClient client = new OkHttpClient(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_test); File sdcache = getExternalCacheDir(); int cacheSize = 10 * 1024 * 1024; // 10 MiB client.setCache(new Cache(sdcache.getAbsoluteFile(), cacheSize)); new Thread(new Runnable() { @Override public void run() { try { execute(); } catch (Exception e) { e.printStackTrace(); } } }).start(); } public void execute() throws Exception { Request request = new Request.Builder() .url("http://publicobject.com/helloworld.txt") .build(); Response response1 = client.newCall(request).execute(); if (!response1.isSuccessful()) throw new IOException("Unexpected code " + response1); String response1Body = response1.body().string(); System.out.println("Response 1 response: " + response1); System.out.println("Response 1 cache response: " + response1.cacheResponse()); System.out.println("Response 1 network response: " + response1.networkResponse()); Response response2 = client.newCall(request).execute(); if (!response2.isSuccessful()) throw new IOException("Unexpected code " + response2); String response2Body = response2.body().string(); System.out.println("Response 2 response: " + response2); System.out.println("Response 2 cache response: " + response2.cacheResponse()); System.out.println("Response 2 network response: " + response2.networkResponse()); System.out.println("Response 2 equals Response 1? " + response1Body.equals(response2Body)); } }okhttpclient有點像Application的概念,統籌著整個okhttp的大功能,通過它設置緩存目錄,我們執行上面的代碼,得到的結果如下
public void execute() throws Exception { Request request = new Request.Builder() .url("http://publicobject.com/helloworld.txt") .build(); Response response1 = client.newCall(request).execute(); if (!response1.isSuccessful()) throw new IOException("Unexpected code " + response1); String response1Body = response1.body().string(); System.out.println("Response 1 response: " + response1); System.out.println("Response 1 cache response: " + response1.cacheResponse()); System.out.println("Response 1 network response: " + response1.networkResponse()); request = request.newBuilder().cacheControl(CacheControl.FORCE_NETWORK).build(); Response response2 = client.newCall(request).execute(); if (!response2.isSuccessful()) throw new IOException("Unexpected code " + response2); String response2Body = response2.body().string(); System.out.println("Response 2 response: " + response2); System.out.println("Response 2 cache response: " + response2.cacheResponse()); System.out.println("Response 2 network response: " + response2.networkResponse()); System.out.println("Response 2 equals Response 1? " + response1Body.equals(response2Body)); }上面的代碼中
request = request.newBuilder().cacheControl(CacheControl.FORCE_NETWORK).build();我們看看運行結果
protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_test); File sdcache = getExternalCacheDir(); int cacheSize = 10 * 1024 * 1024; // 10 MiB //client.setCache(new Cache(sdcache.getAbsoluteFile(), cacheSize)); new Thread(new Runnable() { @Override public void run() { try { execute(); } catch (Exception e) { e.printStackTrace(); System.out.println(e.getMessage().toString()); } } }).start(); } public void execute() throws Exception { Request request = new Request.Builder() .url("http://publicobject.com/helloworld.txt") .build(); Response response1 = client.newCall(request).execute(); if (!response1.isSuccessful()) throw new IOException("Unexpected code " + response1); String response1Body = response1.body().string(); System.out.println("Response 1 response: " + response1); System.out.println("Response 1 cache response: " + response1.cacheResponse()); System.out.println("Response 1 network response: " + response1.networkResponse()); request = request.newBuilder().cacheControl(CacheControl.FORCE_CACHE).build(); Response response2 = client.newCall(request).execute(); if (!response2.isSuccessful()) throw new IOException("Unexpected code " + response2); String response2Body = response2.body().string(); System.out.println("Response 2 response: " + response2); System.out.println("Response 2 cache response: " + response2.cacheResponse()); System.out.println("Response 2 network response: " + response2.networkResponse()); System.out.println("Response 2 equals Response 1? " + response1Body.equals(response2Body)); }取消操作
public void canceltest() throws Exception { Request request = new Request.Builder() .url("http://httpbin.org/delay/2") // This URL is served with a 2 second delay. .build(); final long startNanos = System.nanoTime(); final Call call = client.newCall(request); // Schedule a job to cancel the call in 1 second. executor.schedule(new Runnable() { @Override public void run() { System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f); call.cancel(); System.out.printf("%.2f Canceled call.%n", (System.nanoTime() - startNanos) / 1e9f); } }, 1, TimeUnit.SECONDS); try { System.out.printf("%.2f Executing call.%n", (System.nanoTime() - startNanos) / 1e9f); Response response = call.execute(); System.out.printf("call is cancel:" + call.isCanceled() + "%n"); System.out.printf("%.2f Call was expected to fail, but completed: %s%n", (System.nanoTime() - startNanos) / 1e9f, response); } catch (IOException e) { System.out.printf("%.2f Call failed as expected: %s%n", (System.nanoTime() - startNanos) / 1e9f, e); } }成功取消
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