RxJava retryWhen操作符实现错误重试机制
业务需求
当我们在app里发起网络请求时，可能会因为各种问题导致失败。如何利用RxJava来实现出现错误后重试若干次，并且可以设定重试的时间间隔。
具体实现
网络请求使用Retrofit来做，请求用户信息接口
@GET("/userinfo?noToken=1")
Observable getUserInfoNoToken() ;请求用户信息接口的逻辑代码
userApi.getUserInfoNoToken()
//总共重试3次，重试间隔3000毫秒
.retryWhen(new RetryWithDelay(3, 3000))
.observeOn(AndroidSchedulers.mainThread())
.subscribeOn(Schedulers.io())
.subscribe(new Action1() {
@Override
public void call(Response response) {
String content = new String(((TypedByteArray) response.getBody()).getBytes());
printLog(tvLogs, "", content);
}
}, new Action1() {
@Override
public void call(Throwable throwable) {
throwable.printStackTrace();
}
}); RetryWithDelay代码：
public class RetryWithDelay implements
Func1<Observableextends Throwable>, Observable> {
private final int maxRetries;
private final int retryDelayMillis;
private int retryCount;
public RetryWithDelay(int maxRetries, int retryDelayMillis) {
this.maxRetries = maxRetries;
this.retryDelayMillis = retryDelayMillis;
}
@Override
public Observable call(Observableextends Throwable> attempts) {
return attempts
.flatMap(new Func1>>() {
@Override
public Observable> call(Throwable throwable) {
if (++retryCount <= maxRetries) {
// When this Observable calls onNext, the original Observable will be retried (i.e. re-subscribed).
printLog(tvLogs, "", "get error, it will try after " + retryDelayMillis
+ " millisecond, retry count " + retryCount);
return Observable.timer(retryDelayMillis,
TimeUnit.MILLISECONDS);
}
// Max retries hit. Just pass the error along.
return Observable.error(throwable);
}
});
}
} 如何模拟重试呢？
方法一：把服务器关闭，关闭服务器后，客户端请求接口的必然会报错，看看是不是重试三次。
运行输出：
'get error, it will try after 3000 millisecond, retry count 1'
Main Thread:false, Thread Name:Retrofit-Idle
'get error, it will try after 3000 millisecond, retry count 2'
Main Thread:false, Thread Name:Retrofit-Idle
'get error, it will try after 3000 millisecond, retry count 3'
Main Thread:false, Thread Name:Retrofit-Idle上面是重试三次了，但是我们怎么知道，如果在服务器启动后，在接下的重试中请求成功呢？接下来试试方法二。
方法二：先把服务器关闭，当点击按钮请求的同时，启动Tomcat服务器。
运行输出：
'get error, it will try after 3000 millisecond, retry count 1'
Main Thread:false, Thread Name:Retrofit-Idle
'get error, it will try after 3000 millisecond, retry count 2'
Main Thread:false, Thread Name:Retrofit-Idle
'username:chiclaim,age:007'
Main Thread:true, Thread Name:main可以发现，在第三次重试的时候，服务器可用了。
转自：http://blog.csdn.net/johnny901114/article/details/51539708