okHttp--Retrofit网络缓存设置总结

内容简介：okHttp--Retrofit网络缓存设置总结

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";
    }
}

您的喜欢与回复是我最大的动力－＿－

以上所述就是小编给大家介绍的《okHttp--Retrofit网络缓存设置总结》，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持！

查看所有标签

猜你喜欢:

• 前端实现设置缓存数据定时失效
• Nginx proxy_pass DNS 缓存设置
• [CentOS7]redis设置开机启动，设置密码
• hadoop地址配置、内存配置、守护进程设置、环境设置
• OpenMediaVault 设置
• scrapy代理的设置

本站部分资源来源于网络，本站转载出于传递更多信息之目的，版权归原作者或者来源机构所有，如转载稿涉及版权问题，请联系我们。