Question

Android应用程序，它将在数据库服务器中显示来自外部数据库（Oracle）的数据。只有 Web服务（RESTful）才能实现，所以我决定用Java / Java EE本身开发Web服务。我不想使用PHP或其他一些技术。请建议我继续这样做。

Answer 1

取决于网络服务。它只是RESTful XML吗？ JAX-WS？ JSON？等等。无论哪种方式，都应该像使用HTTP套接字调用并解析响应一样简单。

要创建网络服务，请点击以下链接

RESTful Web Services

使用HTTPClient

public static String hitService(String host, int port, String path, String postBody) throws IOException {
        HttpHost target = new HttpHost(host, port);
        HttpClient client = new DefaultHttpClient();
        HttpGet get = new HttpGet(path);
        HttpEntity results = null;
        try {
            HttpResponse response=client.execute(target, get);
            results = response.getEntity();
            return EntityUtils.toString(results);
        } catch (Exception e) {
            throw new RuntimeException("Web Service Failure");
        } finally {
            if (results!=null)
                try {
                    results.consumeContent();
                } catch (IOException e) {
                    // empty, Checked exception but don't care
                }
        }
    }

Android Cookbook example

Answer 2

CouchDB现在非常流行，它适用于Android。 Watch this video.

Apache CouchDB是一个面向文档的数据库，可以使用JavaScript以MapReduce方式查询和索引。 CouchDB还提供具有双向冲突检测和解决方案的增量复制。

CouchDB提供的RESTful JSON API可以从允许HTTP请求的任何环境访问。有无数的第三方客户端库可以使您选择的编程语言变得更加容易。

Answer 3

public class RestClient {

    private ArrayList <NameValuePair> params;
    private ArrayList <NameValuePair> headers;

    private String url;

    private int responseCode;
    private String message;

    private String response;

    public String getResponse() {
        return response;
    }

    public String getErrorMessage() {
        return message;
    }

    public int getResponseCode() {
        return responseCode;
    }

    public RestClient(String url)
    {
        this.url = url;
        params = new ArrayList<NameValuePair>();
        headers = new ArrayList<NameValuePair>();
    }

    public void AddParam(String name, String value)
    {
        params.add(new BasicNameValuePair(name, value));
    }

    public void AddHeader(String name, String value)
    {
        headers.add(new BasicNameValuePair(name, value));
    }

    public void Execute(RequestMethod method) throws Exception
    {
        switch(method) {
            case GET:
            {
                //add parameters
                String combinedParams = "";
                if(!params.isEmpty()){
                    combinedParams += "?";
                    for(NameValuePair p : params)
                    {
                        String paramString = p.getName() + "=" + URLEncoder.encode(p.getValue(),”UTF-8″);
                        if(combinedParams.length() > 1)
                        {
                            combinedParams  +=  "&" + paramString;
                        }
                        else
                        {
                            combinedParams += paramString;
                        }
                    }
                }

                HttpGet request = new HttpGet(url + combinedParams);

                //add headers
                for(NameValuePair h : headers)
                {
                    request.addHeader(h.getName(), h.getValue());
                }

                executeRequest(request, url);
                break;
            }
            case POST:
            {
                HttpPost request = new HttpPost(url);

                //add headers
                for(NameValuePair h : headers)
                {
                    request.addHeader(h.getName(), h.getValue());
                }

                if(!params.isEmpty()){
                    request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                }

                executeRequest(request, url);
                break;
            }
        }
    }

    private void executeRequest(HttpUriRequest request, String url)
    {
        HttpClient client = new DefaultHttpClient();

        HttpResponse httpResponse;

        try {
            httpResponse = client.execute(request);
            responseCode = httpResponse.getStatusLine().getStatusCode();
            message = httpResponse.getStatusLine().getReasonPhrase();

            HttpEntity entity = httpResponse.getEntity();

            if (entity != null) {

                InputStream instream = entity.getContent();
                response = convertStreamToString(instream);

                // Closing the input stream will trigger connection release
                instream.close();
            }

        } catch (ClientProtocolException e)  {
            client.getConnectionManager().shutdown();
            e.printStackTrace();
        } catch (IOException e) {
            client.getConnectionManager().shutdown();
            e.printStackTrace();
        }
    }

    private static String convertStreamToString(InputStream is) {

        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}

如何从Android应用程序访问Oracle数据库。

3 个答案: