壹、HttpClient網絡訪問：
（壹）、簡介：
1、Apache組織提供了HttpClient項目，可以實現網絡訪問。在Android中，成功集成了HttpClient，所以在Android中可以直接使用HttpClient訪問網絡。
2、與HttpURLConnection相比，HttpClient將前者中的輸入、輸出流操作，統壹封裝成HttpGet、HttpPost、HttpRequest類。
HttpClient：網絡連接對象；
HttpGet：代表發送GET請求；
HttpPost：代表發送POST請求；
HttpResponse：代表處理服務器響應的對象。
HttpEntity對象：該對象中包含了服務器所有的返回內容。
3、使用步驟：（六部曲）重點
創建HttpClient對象：通過實例化DefaultHttpClient獲得；
創建HttpGet或HttpPost對象：通過實例化 HttpGet或HttpPost 獲得，而構造方法的參數是urlstring（即需要訪問的網絡url地址）。也可以通過調用setParams()方法來添加請求參數；
調用HttpClient對象的execute()方法，參數是剛才創建的 HttpGet或HttpPost對象 ，返回值是HttpResponse對象；
通過response對象中的getStatusLine()方法和getStatusCode()方法獲取服務器響應狀態是否是200。
調用 HttpResponse對象的getEntity()方法，返回HttpEntity對象。而該對象中包含了服務器所有的返回內容。
借助EntityUtils的toString()方法或toByteArray()對 HttpEntity對象進行處理，也可以通過IO流對 HttpEntity對象進行操作。
（二）、封裝HttpClientHelper工具類：
public class HttpClientHelper {
public static HttpClient checkNetwork(String url) {
HttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
HttpResponse httpResponse = null;
try {
httpResponse = httpClient.execute(request);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
return httpClient;
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* 作用：實現網絡訪問文件，將獲取到數據儲存在文件流中
*
* @param url
* ：訪問網絡的url地址
* @return inputstream
*/
public static InputStream loadFileFromURL(String url) {
HttpClient httpClient = new DefaultHttpClient();
HttpGet requestGet = new HttpGet(url);
HttpResponse httpResponse;
try {
httpResponse = httpClient.execute(requestGet);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity entity = httpResponse.getEntity();
return entity.getContent();
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 作用：實現網絡訪問文件，將獲取到的數據存在字節數組中
*
* @param url
* ：訪問網絡的url地址
* @return byte[]
*/
public static byte[] loadByteFromURL(String url) {
HttpClient httpClient = new DefaultHttpClient();
HttpGet requestGet = new HttpGet(url);
try {
HttpResponse httpResponse = httpClient.execute(requestGet);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity httpEntity = httpResponse.getEntity();
return EntityUtils.toByteArray(httpEntity);
}
} catch (Exception e) {
e.printStackTrace();
System.out.println("====>" + e.toString());
}
return null;
}
/**
* 作用：實現網絡訪問文件，返回字符串
*
* @param url
* ：訪問網絡的url地址
* @return String
*/
public static String loadTextFromURL(String url) {
HttpClient httpClient = new DefaultHttpClient();
HttpGet requestGet = new HttpGet(url);
try {
HttpResponse httpResponse = httpClient.execute(requestGet);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity httpEntity = httpResponse.getEntity();
return EntityUtils.toString(httpEntity, "utf-8");
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 作用：實現網絡訪問文件，先給服務器通過“GET”方式提交數據，再返回相應的數據
*
* @param url
* ：訪問網絡的url地址
* @param params
* String url：訪問url時，需要傳遞給服務器的參數。
* 第二個參數格式為：username=wangxiangjun&password=123456
* @return byte[]
*/
public static byte[] doGetSubmit(String url, String params) {
HttpClient httpClient = new DefaultHttpClient();
HttpGet requestGet = new HttpGet(url + "?" + params);
try {
HttpResponse httpResponse = httpClient.execute(requestGet);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity httpEntity = httpResponse.getEntity();
return EntityUtils.toByteArray(httpEntity);
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 作用：實現網絡訪問文件，先給服務器通過“POST”方式提交數據，再返回相應的數據
*
* @param url
* ：訪問網絡的url地址
* @param params
* String url：訪問url時，需要傳遞給服務器的參數。 第二個參數為：List<NameValuePair>
* @return byte[]
*/
public static byte[] doPostSubmit(String url, List<NameValuePair> params) {
HttpClient httpClient = new DefaultHttpClient();
HttpPost requestPost = new HttpPost(url);
try {
requestPost.setEntity(new UrlEncodedFormEntity(params, "utf-8"));
HttpResponse httpResponse = httpClient.execute(requestPost);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity httpEntity = httpResponse.getEntity();
return EntityUtils.toByteArray(httpEntity);
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 作用：實現網絡訪問文件，先給服務器通過“POST”方式提交數據，再返回相應的數據
*
* @param url
* ：訪問網絡的url地址
* @param params
* String url：訪問url時，需要傳遞給服務器的參數。 Map<String , Object>
* @return byte[]
*/
public static byte[] doPostSubmit(String url, Map<String, Object> params) {
HttpClient httpClient = new DefaultHttpClient();
HttpPost requestPost = new HttpPost(url);
List<BasicNameValuePair> parameters = new ArrayList<BasicNameValuePair>();
try {
if (params != null) {
for (Map.Entry<String, Object> entry : params.entrySet()) {
String key = entry.getKey();
String value = entry.getValue().toString();
BasicNameValuePair nameValuePair = new BasicNameValuePair(
key, value);
parameters.add(nameValuePair);
}
}
requestPost
.setEntity(new UrlEncodedFormEntity(parameters, "utf-8"));
HttpResponse httpResponse = httpClient.execute(requestPost);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity httpEntity = httpResponse.getEntity();
return EntityUtils.toByteArray(httpEntity);
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}