RxJava 嵌套回调

RxJava 重构的一个嵌套回调

需求：将百度地图的 js文件缓存到本地。百度地图js API需要引入一个js文件，为了提高地图加载速度，决定将js文件缓存到本地。

1. http://api.map.baidu.com/api?v=2.0&ak=xNUVOanwO3w8XGGPT403G2Ks
2. 访问url 得到一个函数，函数中包含一个script引入一个js文件，截取url下载文件。

一： 传统的方式

        private void getNewFileAddress() {

            httpUtils.send(HttpMethod.GET, address, new RequestCallBack() {

                @Override
                public void onFailure(HttpException exception, String arg1) {
                }

                @Override
                public void onSuccess(ResponseInfo response) {
                    String result = response.result;
                    Matcher m  = Pattern.compile("[a-zA-z]+://[^\\s\"]*").matcher(result); //匹配src
                    if(m.find()){
                        cacheMapFile(m.group());
                        Log.i(TAG, "截取到的ip地址为"+m.group());
                    }

                }
            });
        }
        private void cacheMapFile(String address) {
            // 缓存的map文件
            final File target = new File(Environment.getExternalStorageDirectory(),"baidu-map.js");         
            httpUtils.send(HttpMethod.GET, address, new RequestCallBack() {

                @Override
                public void onFailure(HttpException arg0, String response) {                    
                }

                @Override
                public void onSuccess(ResponseInfo response) {
                    String result = response.result;
                    try {
                        //将js文件保存到本地
                        IOUtils.write(result, new FileOutputStream(target));

                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        }

使用RxJava

public class CacheMapService {
    private String TAG = "debug";
    public void cache(){        
        RestAdapter adapter = new RestAdapter.Builder()
        .setConverter(new CustomConvert())
        .setEndpoint("http://api.map.baidu.com")
        .build();
        GetUrl getUrl = adapter.create(GetUrl.class);
            getUrl.getUrl()
            .map(new Func1() {
                @Override
                public String call(String address) {
                    Matcher m  = Pattern.compile("[a-zA-z]+://[^\\s\"]*").matcher(address); //匹配src
                    if(m.find()){
                        return m.group();
                    }
                    return null;
                }
            })
            .map(new Func1() {

                @Override
                public Boolean call(String url) {
                    RestAdapter adapter = new RestAdapter.Builder()
                    .setConverter(new CustomConvert())
                    .setEndpoint(url)
                    .build();
                    String path = String.format("%s/%s", Environment.getExternalStorageDirectory().getAbsolutePath(),"baidu-map.js");
                    String content = adapter.create(GetCacheFile.class).cacheFile();
                    FileOutputStream out = null;
                    try {
                        out = new FileOutputStream(new File(path));
                        IOUtils.write(content, out);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }finally{
                        IOUtils.closeQuietly(out);
                    }
                    return true;
                }
            }).subscribe(new Action1() {

                @Override
                public void call(Boolean arg0) {
                    Log.i(TAG, "end...."+arg0);
                }
            });
    }
    public interface GetUrl{
        @GET("/api?v=2.0&ak=xNUVOanwO3w8XGGPT403G2Ks")
        Observable getUrl();
    }
    public interface GetCacheFile{
        @GET("/")
        String cacheFile();
    }
    class CustomConvert implements Converter{

        private InputStream in;

        @Override
        public Object fromBody(TypedInput typeInput, Type type)
                throws ConversionException {
            try {
                in = typeInput.in();
            } catch (IOException e) {
                e.printStackTrace();
            }
            String response = null;
            try {
                response = fromString(in);
            } catch (IOException e) {
                e.printStackTrace();
            };
            return response;
        }

        private String fromString(InputStream in) throws IOException {
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            StringBuilder sb = new StringBuilder();
            String line;
            while((line=reader.readLine()) != null){
                sb.append(line);
            }
            return sb.toString();
        }

        @Override
        public TypedOutput toBody(Object obj) {
            return null;
        }

    }
}

对比完，使用RxJava代码可能更加繁琐，但是逻辑确很清晰。