概述
随着Google对HttpClient 摒弃,和Volley的逐渐没落,OkHttp开始异军突起,而Retrofit则对okHttp进行了强制依赖。
Retrofit是由Square公司出品的针对于Android和Java的类型安全的Http客户端，
如果看源码会发现其实质上就是对okHttp的封装，使用面向接口的方式进行网络请求，利用动态生成的代理类封装了网络接口请求的底层,
其将请求返回javaBean，对网络认证 REST API进行了很好对支持此，使用Retrofit将会极大的提高我们应用的网络体验。
REST
既然是RESTful架构,那么我们就来看一下什么是REST吧。
REST(REpresentational State Transfer)是一组架构约束条件和原则。
RESTful架构都满足以下规则：
（1）每一个URI代表一种资源；
（2）客户端和服务器之间，传递这种资源的某种表现层；
（3）客户端通过四个HTTP动词，对服务器端资源进行操作，实现”表现层状态转化”。
下面话不多说了，来开始本文的正文吧
1. 需求与前提
base url
默认base url: https://cloud.devwiki.net
测试版 url : https://dev.devwiki.net
私有云版本url: https://private.devwiki.net
rest 版本
- /rest/v1/
- /rest/v2/
- /rest/v3/
需求点
- 大部分接口使用 cloud host, 部分接口使用 private host
- 大部分接口使用 rest/v3 版本, 部分接口使用 v2, v1版本.
- 每个host 都有可能存在 rest v1, v2, v3的接口
2. 实现思路
okhttp 可以添加拦截器, 可在发起访问前进行拦截, 通常我们会在 拦截器中统一添加 header, 比如:
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class HeaderInterceptor implements Interceptor { private static final String ENCODING_GZIP = "gzip"; private static final String CONTENT_TYPE_JSON = "application/json;charset=UTF-8"; private static final String HEADER_CONTENT_TYPE = "Content-Type"; private static final String HEADER_ACCEPT_TYPE = "application/json"; private static final String HEADER_CONTENT_ENCODING = "Content-Encoding"; private final static String CHARSET = "UTF-8"; @Override public Response intercept(Chain chain) throws IOException { Request originRequest = chain.request(); Request.Builder newBuilder = originRequest.newBuilder(); newBuilder.addHeader("Accept", HEADER_ACCEPT_TYPE); newBuilder.addHeader("Accept-Charset", CHARSET); newBuilder.addHeader("Accept-Encoding", ENCODING_GZIP); newBuilder.addHeader("Accept-Language", Locale.getDefault().toString().replace("_", "-")); newBuilder.addHeader(HEADER_CONTENT_TYPE, CONTENT_TYPE_JSON); return chain.proceed(newBuilder.build()); }} |
同理我们也可以在所有请求中添加统一的uuid 或者 key 进行防劫持或者认证. 比如:
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Request originRequest = chain.request();if (paramsMap != null) { HttpUrl originUrl = originRequest.url(); HttpUrl.Builder newBuilder = originUrl.newBuilder(); for (String key : paramsMap.keySet()) { newBuilder.addEncodedQueryParameter(key, paramsMap.get(key)); } HttpUrl newUrl = newBuilder.build(); Request newRequest = originRequest.newBuilder().url(newUrl).build(); return chain.proceed(newRequest);}return chain.proceed(originRequest); |
那么, 同样我们可以再拦截器中进行host 和 path的替换, 那么怎么替换呢?
3. 实现过程
3.1 定义host 类型和 rest 版本
host类型:
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interface HostName { String CLOUD = "CLOUD"; String PRIVATE = "PRIVATE"; String DEV = "DEV";} interface HostValue { String CLOUD = "https://www.baidu.com"; String PRIVATE = "https://private.bidu.com"; String DEV = "https://dev.baidu.com";} |
rest 版本:
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interface RestVersionCode { String EMPTY = "EMPTY"; String V1 = "V1"; String V2 = "V2"; String PRIVATE = "PRIVATE";} /** * path 前缀值 */interface RestVersionValue { String EMPTY = ""; String V1 = "rest/v1"; String V2 = "rest/v2"; String PRIVATE = "rest/private";} |
设置一个默认的 host 和 rest 版本, 然后在需要更改host和rest 版本的请求接口处添header, 根据header设置来变更.
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interface BaiduApiService { @GET("s") Observable<Response<Object>> search(@Query("wd")String wd); @GET("s") @Headers({UrlConstants.Header.REST_VERSION_V1}) Observable<Response<Object>> searchChangePath(@Query("wd")String wd); @GET("s") @Headers({UrlConstants.Header.HOST_DEV}) Observable<Response<Object>> searchChangeHost(@Query("wd")String wd); @Headers({UrlConstants.Header.HOST_PRIVATE, UrlConstants.Header.REST_VERSION_PRIVATE}) @GET("s") Observable<Response<Object>> searchChangeHostPath(@Query("wd")String wd);} |
header 的可选值:
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interface Header { String SPLIT_COLON = ":"; String HOST = "HostName"; String HOST_CLOUD = HOST + SPLIT_COLON + HostName.CLOUD; String HOST_PRIVATE = HOST + SPLIT_COLON + HostName.PRIVATE; String HOST_DEV = HOST + SPLIT_COLON + HostName.DEV; String REST_VERSION = "RestVersion"; String REST_VERSION_V1 = REST_VERSION + SPLIT_COLON + RestVersionCode.V1; String REST_VERSION_V2 = REST_VERSION + SPLIT_COLON + RestVersionCode.V2; String REST_VERSION_PRIVATE = REST_VERSION + SPLIT_COLON + RestVersionCode.PRIVATE; String REST_VERSION_EMPTY = REST_VERSION + SPLIT_COLON + RestVersionCode.EMPTY;} |
然后是解析:
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class RequestInterceptor implements Interceptor { @Override public Response intercept(Chain chain) throws IOException { Request originRequest = chain.request(); HttpUrl originUrl = originRequest.url(); HttpUrl.Builder newBuilder; String hostType = originRequest.header(UrlConstants.Header.HOST); System.out.println("hostType:" + hostType); if (hostType != null && hostType.length() > 0) { String hostValue = UrlManager.getInstance().getHost(hostType); HttpUrl temp = HttpUrl.parse(hostValue); if (temp == null) { throw new IllegalArgumentException(hostType + "对应的host地址不合法:" + hostValue); } newBuilder = temp.newBuilder(); } else { newBuilder = new HttpUrl.Builder() .scheme(originUrl.scheme()) .host(originUrl.host()) .port(originUrl.port()); } String restVersion = originRequest.header(UrlConstants.Header.REST_VERSION); System.out.println("restVersion:" + restVersion); if (restVersion == null) { restVersion = UrlConstants.RestVersionCode.V2; } String restValue = UrlManager.getInstance().getRest(restVersion); if (restValue.contains("/")) { String[] paths = restValue.split("/"); for (String path : paths) { newBuilder.addEncodedPathSegment(path); } } else { newBuilder.addEncodedPathSegment(restValue); } for (int i = 0; i < originUrl.pathSegments().size(); i++) { newBuilder.addEncodedPathSegment(originUrl.encodedPathSegments().get(i)); } newBuilder.encodedPassword(originUrl.encodedPassword()) .encodedUsername(originUrl.encodedUsername()) .encodedQuery(originUrl.encodedQuery()) .encodedFragment(originUrl.encodedFragment()); HttpUrl newUrl = newBuilder.build(); System.out.println("newUrl:" + newUrl.toString()); Request newRequest = originRequest.newBuilder().url(newUrl).build(); return chain.proceed(newRequest); }} |
为了能动态设置host, 我们需要一个map来存储host 类型和值.
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private Map<String, String> hostMap;private Map<String, String> restMap; private UrlManager() { hostMap = new HashMap<>(16); for (UrlConstants.Host host : UrlConstants.Host.values()) { hostMap.put(host.getName(), host.getValue()); } restMap = new HashMap<>(); for (UrlConstants.Rest rest : UrlConstants.Rest.values()) { restMap.put(rest.getVersion(), rest.getValue()); }} //更新host 的值public void setHost(String name, String value) { if (hostMap.containsKey(name)) { HttpUrl httpUrl = HttpUrl.parse(value); if (httpUrl == null) { throw new IllegalArgumentException("要存入的Host " + name + "对应的value:" + value + "不合法!"); } hostMap.put(name, value); } else { throw new NoSuchElementException("没有找到已经定义的Host名称:" + name + ",请先在" + "net.devwiki.manager.UrlConstants.Host中定义!"); }} //根据host 获取值public String getHost(String name) { if (!hostMap.containsKey(name)) { throw new NoSuchElementException("没有找到已经定义的Host名称:" + name + ",请先在" + "net.devwiki.manager.UrlConstants.Host中定义!"); } return hostMap.get(name);} |
这样就可以动态替换host 和 rest版本了.
4.测试运行
测试代码:
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private static void testRequest() { BaiduRest rest = new BaiduRest(); testDefault(rest); testChangeHost(rest); testChangePath(rest); testChangeHostPath(rest);} |
测试运行结果:
ostType:null
restVersion:null
newUrl:https://www.baidu.com/rest/v2/s?wd=123
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://www.baidu.com/rest/v2/s?wd=123 http/1.1
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: <-- 302 Found https://www.baidu.com/rest/v2/s?wd=123 (83ms, 154-byte body)
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: --> GET http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf http/1.1
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: <-- 200 OK http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf (46ms, unknown-length body)
hostType:DEV
restVersion:null
newUrl:https://dev.baidu.com/rest/v2/s?wd=123
九月 07, 2018 11:36:58 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://dev.baidu.com/rest/v2/s?wd=123 http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 302 Found https://dev.baidu.com/rest/v2/s?wd=123 (154ms, 154-byte body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET http://developer.baidu.com/error.html http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 301 Moved Permanently http://developer.baidu.com/error.html (18ms, 73-byte body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://developer.baidu.com/error.html http/1.1
hostType:null
restVersion:V1
newUrl:https://www.baidu.com/rest/v1/s?wd=123
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 200 OK https://developer.baidu.com/error.html (157ms, unknown-length body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET https://www.baidu.com/rest/v1/s?wd=123 http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 302 Found https://www.baidu.com/rest/v1/s?wd=123 (46ms, 154-byte body)
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: --> GET http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf http/1.1
九月 07, 2018 11:36:59 上午 okhttp3.internal.platform.Platform log
信息: <-- 200 OK http://www.baidu.com/s?wd=123&tn=SE_PSStatistics_p1d9m0nf (54ms, unknown-length body)
hostType:PRIVATE
restVersion:PRIVATE
newUrl:https://private.bidu.com/rest/private/s?wd=123
结果按照设置进行了host 和 rest 的变更.
5. 项目代码
项目代码地址: Dev-Wiki/OkHttpDemo
总结
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对服务器之家的支持。
原文链接：http://blog.devwiki.net/index.php/2018/09/08/change-retrofit-base-url-and-rest-version.html
