转载请标明出处：http://www.jianshu.com/p/241e6af94390
本文出自:Jlanglang
前言
找了些文章,发现说的都不是很清楚.设置始终有点问题
这个配置,每个人的需求不一样,实现情况肯定也不一样.
说说我的需求:
1.有网的时候所有接口不使用缓存
2.指定的接口产生缓存文件,其他接口不会产生缓存文件
3.无网的时候指定的接口使用缓存数据.其他接口不使用缓存数据
1.网络拦截器(关键)
提示:只能缓存Get请求
Interceptor cacheInterceptor = new Interceptor() {
@Override
public Response intercept(Chain chain) throws IOException {
//拿到请求体
Request request = chain.request();
//读接口上的@Headers里的注解配置
String cacheControl = request.cacheControl().toString();
//判断没有网络并且添加了@Headers注解,才使用网络缓存.
if (!Utils.isOpenInternet()&&!TextUtils.isEmpty(cacheControl)){
//重置请求体;
request = request.newBuilder()
//强制使用缓存
.cacheControl(CacheControl.FORCE_CACHE)
.build();
}
//如果没有添加注解,则不缓存
if (TextUtils.isEmpty(cacheControl) || "no-store" .contains(cacheControl)) {
//响应头设置成无缓存
cacheControl = "no-store";
} else if (Utils.isOpenInternet()) {
//如果有网络,则将缓存的过期时间,设置为0,获取最新数据
cacheControl = "public, max-age=" + 0;
}else {
//...如果无网络,则根据@headers注解的设置进行缓存.
}
Response response = chain.proceed(request);
HLog.i("httpInterceptor", cacheControl);
return response.newBuilder()
.header("Cache-Control", cacheControl)
.removeHeader("Pragma")
.build();
};
具体接口中的使用,添加headers:
/**
* 只能缓存get请求.
* 这里我设置了1天的缓存时间
* 接口随便写的.哈哈,除了 @Headers(...),其它代码没啥参考价值.
*/
@Headers("Cache-Control: public, max-age=" + 24 * 3600)
@GET("url")
Observable<?> queryInfo(@Query("userName") String userName);
关于Cache-Control头的参数说明:
public 所有内容都将被缓存(客户端和代理服务器都可缓存)
private 内容只缓存到私有缓存中(仅客户端可以缓存，代理服务器不可缓存)
no-cache no-cache是会被缓存的，只不过每次在向客户端（浏览器）提供响应数据时，缓存都要向服务器评估缓存响应的有效性。
no-store 所有内容都不会被缓存到缓存或 Internet 临时文件中
max-age=xxx (xxx is numeric) 缓存的内容将在 xxx 秒后失效, 这个选项只在HTTP 1.1可用, 并如果和Last-Modified一起使用时, 优先级较高
max-stale和max-age一样，只能设置在请求头里面。
同时设置max-stale和max-age，缓存失效的时间按最长的算。(这个其实不用纠结)
还有2个参数:
CacheControl.FORCE_CACHE 强制使用缓存,如果没有缓存数据,则抛出504(only-if-cached)
CacheControl.FORCE_NETWORK 强制使用网络,不使用任何缓存.
这两个设置,不会判断是否有网.需要自己写判断.
设置错误会导致,数据不刷新,或者有网情况下,请求不到数据
这两个很关键..可以根据自己的需求,进行切换.
2.设置OkHttpClient
OkHttpClient client = new OkHttpClient.Builder()
//添加log拦截器,打印log信息,代码后面贴出
.addInterceptor(loggingInterceptor)
//添加上面代码的拦截器,设置缓存
.addNetworkInterceptor(cacheInterceptor)
//这个也要添加,否则无网的时候,缓存设置不会生效
.addInterceptor(cacheInterceptor)
//设置缓存目录,以及最大缓存的大小,这里是设置10M
.cache(new Cache(MyApplication.getContext().getCacheDir(), 10240 * 1024))
.build();
3.完整的代码:
public class RetrofitUtil {
/**
* 服务器地址
*/
private static final String API_HOST = Constant.URLS.BASEURL;
private RetrofitUtil() {
}
public static Retrofit getRetrofit() {
return Instanace.retrofit;
}
private static Retrofit getInstanace() {
HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor(new HttpLoggingInterceptor.Logger() {
@Override
public void log(String message) {
HLog.i("RxJava", message);
}
});
Interceptor cacheInterceptor = new Interceptor() {
@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
//有网的时候,读接口上的@Headers里的注解配置
String cacheControl = request.cacheControl().toString();
//没有网络并且添加了注解,才使用缓存.
if (!Utils.isOpenInternet()&&!TextUtils.isEmpty(cacheControl)){
//重置请求体;
request = request.newBuilder()
.cacheControl(CacheControl.FORCE_CACHE)
.build();
}
//如果没有添加注解,则不缓存
if (TextUtils.isEmpty(cacheControl) || "no-store" .contains(cacheControl)) {
//响应头设置成无缓存
cacheControl = "no-store";
} else if (Utils.isOpenInternet()) {
//如果有网络,则将缓存的过期事件,设置为0,获取最新数据
cacheControl = "public, max-age=" + 0;
}else {
//...如果无网络,则根据@headers注解的设置进行缓存.
}
Response response = chain.proceed(request);
HLog.i("httpInterceptor", cacheControl);
return response.newBuilder()
.header("Cache-Control", cacheControl)
.removeHeader("Pragma")
.build();
}
};
OkHttpClient client = new OkHttpClient.Builder()
.addInterceptor(loggingInterceptor)
.addNetworkInterceptor(cacheInterceptor)
.addInterceptor(cacheInterceptor)
.cache(new Cache(MyApplication.getContext().getCacheDir(), 10240 * 1024))
.build();
return new Retrofit.Builder()
.client(client)
.baseUrl(API_HOST)
.addConverterFactory(FastjsonConverterFactory.create())
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.build();
}
private static class Instanace {
private static final Retrofit retrofit = getInstanace();
}
}
附上HttpLoggingInterceptor
/**
* Created by Sunflower on 2016/1/12.
*/
public class HttpLoggingInterceptor implements Interceptor {
private static final Charset UTF8 = Charset.forName("UTF-8");
public enum Level {
/**
* No logs.
*/
NONE,
/**
* Logs request and response lines.
* <p/>
* Example:
* <pre>{@code
* --> POST /greeting HTTP/1.1 (3-byte body)
* <p/>
* <-- HTTP/1.1 200 OK (22ms, 6-byte body)
* }</pre>
*/
BASIC,
/**
* Logs request and response lines and their respective headers.
* <p/>
* Example:
* <pre>{@code
* --> POST /greeting HTTP/1.1
* Host: example.com
* Content-Type: plain/text
* Content-Length: 3
* --> END POST
* <p/>
* <-- HTTP/1.1 200 OK (22ms)
* Content-Type: plain/text
* Content-Length: 6
* <-- END HTTP
* }</pre>
*/
HEADERS,
/**
* Logs request and response lines and their respective headers and bodies (if present).
* <p/>
* Example:
* <pre>{@code
* --> POST /greeting HTTP/1.1
* Host: example.com
* Content-Type: plain/text
* Content-Length: 3
* <p/>
* Hi?
* --> END GET
* <p/>
* <-- HTTP/1.1 200 OK (22ms)
* Content-Type: plain/text
* Content-Length: 6
* <p/>
* Hello!
* <-- END HTTP
* }</pre>
*/
BODY
}
public interface Logger {
void log(String message);
/**
* A {@link Logger} defaults output appropriate for the current platform.
*/
Logger DEFAULT = new Logger() {
@Override
public void log(String message) {
Platform.get().log(Platform.WARN,message,null);
}
};
}
public HttpLoggingInterceptor() {
this(Logger.DEFAULT);
}
public HttpLoggingInterceptor(Logger logger) {
this.logger = logger;
}
private final Logger logger;
private volatile Level level = Level.BODY;
/**
* Change the level at which this interceptor logs.
*/
public HttpLoggingInterceptor setLevel(Level level) {
if (level == null) throw new NullPointerException("level == null. Use Level.NONE instead.");
this.level = level;
return this;
}
@Override
public Response intercept(Chain chain) throws IOException {
Level level = this.level;
Request request = chain.request();
if (level == Level.NONE) {
return chain.proceed(request);
}
boolean logBody = level == Level.BODY;
boolean logHeaders = logBody || level == Level.HEADERS;
RequestBody requestBody = request.body();
boolean hasRequestBody = requestBody != null;
String requestStartMessage = request.method() + ' ' + request.url();
if (!logHeaders && hasRequestBody) {
requestStartMessage += " (" + requestBody.contentLength() + "-byte body)";
}
logger.log(requestStartMessage);
if (logHeaders) {
if (!logBody || !hasRequestBody) {
logger.log("--> END " + request.method());
} else if (bodyEncoded(request.headers())) {
logger.log("--> END " + request.method() + " (encoded body omitted)");
} else if (request.body() instanceof MultipartBody) {
//如果是MultipartBody，会log出一大推乱码的东东
} else {
Buffer buffer = new Buffer();
requestBody.writeTo(buffer);
Charset charset = UTF8;
MediaType contentType = requestBody.contentType();
if (contentType != null) {
contentType.charset(UTF8);
}
logger.log(buffer.readString(charset));
// logger.log(request.method() + " (" + requestBody.contentLength() + "-byte body)");
}
}
long startNs = System.nanoTime();
Response response = chain.proceed(request);
long tookMs = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNs);
logger.log(response.code() + ' ' + response.message() + " (" + tookMs + "ms" + ')');
return response;
}
private boolean bodyEncoded(Headers headers) {
String contentEncoding = headers.get("Content-Encoding");
return contentEncoding != null && !contentEncoding.equalsIgnoreCase("identity");
}
private static String protocol(Protocol protocol) {
return protocol == Protocol.HTTP_1_0 ? "HTTP/1.0" : "HTTP/1.1";
}
}
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