因为之前参与的网络开发项目都遇到一些相同的问题：
- 大量的并发请求造成堵塞，特别是遇上让人无语的
3G网络，无限loading。。。 - 一般来说一个网络请求都会用使用到一个异步线程，大量的线程创建、运行、销毁又造成了系统资源的浪费
- 请求结束得到结果后，如果需要更新
UI，一个不小心忘了返回UI线程，各种崩溃。。。
前些日子跟同事商量能不能做个请求队列去进行控制，于是趁着热度没消退说干就干，建了个模型，以备日后使用。
在这个模型中，有高中低三个优先级信道如下：高优先级–1，中优先级–3，低优先级–2
规则：
1.正常情况下各个优先级使用各自信道（线程）
2.高级信道满载、中、低级信道空置，则高级请求可使用低级信道
构思：
UI线程将期望的网络请求url和参数通过一个封装好的Runnable提交给Service处理（当然也可以交给一个Thread处理，本例使用Service），Service接收到请求，判断优先级，加入到相应线程池中排队。线程池启动线程发起网络请求，最后通过监听器将结果返回给Service，Service发送广播通知UI线程，UI线程更新相关界面，结束。
废话说完，上例子，首先是封装好的Runnable：
public class HttpConnRunnable implements Runnable, Parcelable {
public static final int HIGH_LEVEL = 0;
public static final int NORMAL_LEVEL = 1;
public static final int LOW_LEVEL = 2;
private int mPriority = NORMAL_LEVEL;//优先级，默认为普通
private String mUrl = "";
private HttpConnListener mListener;//监听器
public HttpConnRunnable() {
super();
}
public HttpConnRunnable(int priority) {
super();
mPriority = priority;
}
@Override
public void run() {
Log.i(Thread.currentThread().getName(), "----Start to connect:" + mUrl + ", priority:" + mPriority + "-----");
try {
Thread.sleep(10000);
//TODO:进行网络请求相关操作，并通过listener返回结果
mListener.onSucceed("Connected to " + mUrl + " succeed!");
}
catch (InterruptedException e) {
e.printStackTrace();
}
Log.i(Thread.currentThread().getName(), "----Finish to connect:" + mUrl + ", priority:" + mPriority + "-----");
}
public int getPriority() {
return mPriority;
}
public void setPriority(int priority) {
mPriority = priority;
}
public String getURL() {
return mUrl;
}
public void setURL(String url) {
mUrl = url;
}
public void setHttpConnListener(HttpConnListener listener) {
mListener = listener;
}
//序列化，为了传递给Service，如果是使用Thread处理本例，则无需序列化
public static final Parcelable.Creator<HttpConnRunnable> CREATOR = new Creator<HttpConnRunnable>() {
@Override
public HttpConnRunnable createFromParcel(Parcel source) {
HttpConnRunnable data = null;
Bundle bundle = source.readBundle();
if(bundle != null) {
data = new HttpConnRunnable(bundle.getInt("PRIORITY"));
data.mUrl = bundle.getString("URL");
}
return data;
}
@Override
public HttpConnRunnable[] newArray(int size) {
return new HttpConnRunnable[size];
}
};
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
Bundle bundle = new Bundle();
bundle.putInt("PRIORITY", mPriority);
bundle.putString("URL", mUrl);
dest.writeBundle(bundle);
}
}
然后是Service的处理:
public class HttpConnService extends Service implements HttpConnListener {
public static final String HTTP_POOL_PARAM_KEYWORD = "HttpPoolParam"; //网络参数传递的关键字
private final int HIGH_POOL_SIZE = 1;
private final int NORMAL_POOL_SIZE = 3;
private final int LOW_POOL_SIZE = 2;
// 可重用固定线程数的线程池
private ThreadPoolExecutor mHighPool;
private ThreadPoolExecutor mNormalPool;
private ThreadPoolExecutor mLowPool;
@Override
public void onCreate() {
//初始化所有
mHighPool = (ThreadPoolExecutor) Executors.newFixedThreadPool(HIGH_POOL_SIZE);
mNormalPool = (ThreadPoolExecutor) Executors.newFixedThreadPool(NORMAL_POOL_SIZE);
mLowPool = (ThreadPoolExecutor) Executors.newFixedThreadPool(LOW_POOL_SIZE);
super.onCreate();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
//接受到来自UI线程的请求
//取出Runnable，并加入到相应队列
Bundle bundle = intent.getExtras();
HttpConnRunnable httpConnRunnable = bundle.getParcelable(HTTP_POOL_PARAM_KEYWORD);
if (httpConnRunnable != null) {
httpConnRunnable.setHttpConnListener(HttpConnService.this);
int level = httpConnRunnable.getPriority();
switch (level) {
case HttpConnRunnable.HIGH_LEVEL:
//如果高级池满而低级池未满交由低级池处理
//如果高级池满而普通池未满交由普通池处理
//如果高级池未满则交给高级池处理，否则，交由高级池排队等候
if (mHighPool.getActiveCount() == HIGH_POOL_SIZE && mLowPool.getActiveCount() < LOW_POOL_SIZE) {
mLowPool.execute(httpConnRunnable);
}
else if (mHighPool.getActiveCount() == HIGH_POOL_SIZE && mNormalPool.getActiveCount() < NORMAL_POOL_SIZE) {
mNormalPool.execute(httpConnRunnable);
}
else {
mHighPool.execute(httpConnRunnable);
}
break;
case HttpConnRunnable.NORMAL_LEVEL:
//如果普通池满而低级池未满交由低级池处理
//如果普通池未满则交给普通池处理，否则，交由普通池排队等候
if (mNormalPool.getActiveCount() == NORMAL_POOL_SIZE && mLowPool.getActiveCount() < LOW_POOL_SIZE) {
mLowPool.execute(httpConnRunnable);
}
else {
mNormalPool.execute(httpConnRunnable);
}
break;
case HttpConnRunnable.LOW_LEVEL:
mLowPool.execute(httpConnRunnable);
break;
}
}
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
mHighPool.shutdownNow();
mNormalPool.shutdownNow();
mLowPool.shutdownNow();
mNormalPool = null;
mLowPool = null;
super.onDestroy();
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onSucceed(String result) {
Intent intent = new Intent();
intent.setAction("com.ezstudio.connpool.HttpConnReceiver");
// 要发送的内容
intent.putExtra("RESULT", result);
// 发送 一个无序广播
sendBroadcast(intent);
}
@Override
public void onFailed() {
// TODO Auto-generated method stub
}
}
最后的Receiver处理比较简单：
public class HttpConnReceiver extends BroadcastReceiver {
private HttpConnListener mListener;
public void setHttpConnListener (HttpConnListener listener) {
mListener = listener;
}
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action.equals("com.ezstudio.connpool.HttpConnReceiver")) {
String result = intent.getStringExtra("RESULT");
mListener.onSucceed(result);
}
}
}
ok,流程走完了，写个测试界面：
看结果非常满意：
05-03 16:42:20.225: I/HighPollingThread(2318): ----HighQuqeue is empty-----
05-03 16:42:20.225: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:20.233: I/LowPollingThread(2318): ----LowQuqeue is empty-----
05-03 16:42:20.233: I/HighPollingThread(2318): ----HighQuqeue is empty-----
05-03 16:42:20.233: I/pool-1-thread-1(2318): ----Start to connect:www.0.com, priority:0-----
05-03 16:42:22.374: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:22.374: I/pool-2-thread-1(2318): ----Start to connect:www.1.com, priority:1-----
05-03 16:42:22.780: I/LowPollingThread(2318): ----LowQuqeue is empty-----
05-03 16:42:22.780: I/pool-3-thread-1(2318): ----Start to connect:www.2.com, priority:2-----
05-03 16:42:23.428: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:23.428: I/pool-2-thread-2(2318): ----Start to connect:www.3.com, priority:1-----
05-03 16:42:23.835: I/HighPollingThread(2318): ----HighQuqeue is empty-----
05-03 16:42:23.835: I/pool-3-thread-2(2318): ----Start to connect:www.4.com, priority:0-----
05-03 16:42:24.171: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:24.171: I/pool-2-thread-3(2318): ----Start to connect:www.5.com, priority:1-----
05-03 16:42:24.507: I/LowPollingThread(2318): ----LowQuqeue is empty-----
05-03 16:42:24.764: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:25.030: I/HighPollingThread(2318): ----HighQuqeue is empty-----
05-03 16:42:25.335: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:25.647: I/LowPollingThread(2318): ----LowQuqeue is empty-----
05-03 16:42:25.936: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:26.163: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:26.389: I/NormalPollingThread(2318): ----NormalQuqeue is empty-----
05-03 16:42:26.694: I/LowPollingThread(2318): ----LowQuqeue is empty-----
总结：
如果不算Service一共最多使用了3个线程池，6个线程，或许可以考虑将三个池合并为一个。但却也大量减少了单独发起请求时的线程创建和销毁的消耗。
