如何在Android开发中用HttpClient连接网络数据-
//添加http头信息
httppost.addHeader(Authorization, your token); //认证token
httppost.addHeader(Content-Type, application/json);
httppost.addHeader(User-Agent, imgfornote);
//http post的json数据格式: {name: your name,parentId: id_of_parent}
JSONObject obj = new JSONObject();
obj.put(name, your name);
obj.put(parentId, your parentid);
httppost.setEntity(new StringEntity(obj.toString()));
HttpResponse response;
response = httpclient.execute(httppost);
//检验状态码,如果成功接收数据
int code = response.getStatusLine().getStatusCode();
if (code == 200) {
String rev = EntityUtils.toString(response.getEntity());//返回json格式: {id: 27JpL~j4vsL0LX00E00005,version: abc}
obj = new JSONObject(rev);
String id = obj.getString(id);
String version = obj.getString(version);}} catch (ClientProtocolException e) {
} catch (Exception e) {}}主要用到的类有:org.apache.http.client.HttpClient 、org.apache.http.client.methods.HttpPost 和org.json.JSONObject
1
构造完整的URL
2
设置一段间隔时间参数,保证HTTP连接顺利建立成功
3
构造HttpClient的实例,并传入Httpparams参数
4
创建GET方法的实例,并传入URL地址
5
使用httpclient执行httpGet进行联网,返回httpResponse(带有数据)
6
获得返回结果,并将数据变成String类型,方便使用JSON进行解析
一、HttpClient网络访问:
(一)、简介:
1、Apache组织提供了HttpClient项目,可以实现网络访问。在Android中,成功集成了HttpClient,所以在Android中可以直接使用HttpClient访问网络。
2、与HttpURLConnection相比,HttpClient将前者中的输入、输出流操作,统一封装成HttpGet、HttpPost、HttpRequest类。
HttpClient:网络连接对象;
HttpGet:代表发送GET请求;
HttpPost:代表发送POST请求;
HttpResponse:代表处理服务器响应的对象。
HttpEntity对象:该对象中包含了服务器所有的返回内容。
3、使用步骤:(六部曲)【重点】
创建HttpClient对象:通过实例化DefaultHttpClient获得;
创建HttpGet或HttpPost对象:通过实例化 HttpGet或HttpPost 获得,而构造方法的参数是urlstring(即需要访问的网络url地址)。也可以通过调用setParams()方法来添加请求参数;
调用HttpClient对象的execute()方法,参数是刚才创建的 HttpGet或HttpPost对象 ,返回值是HttpResponse对象;
通过response对象中的getStatusLine()方法和getStatusCode()方法获取服务器响应状态是否是200。
调用 HttpResponse对象的getEntity()方法,返回HttpEntity对象。而该对象中包含了服务器所有的返回内容。
借助EntityUtils的toString()方法或toByteArray()对 HttpEntity对象进行处理,也可以通过IO流对 HttpEntity对象进行操作。
(二)、封装HttpClientHelper工具类:
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:实现网络访问文件,将获取到数据储存在文件流中
*
* @param url
* :访问网络的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:实现网络访问文件,将获取到的数据存在字节数组中
*
* @param url
* :访问网络的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:实现网络访问文件,返回字符串
*
* @param url
* :访问网络的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:实现网络访问文件,先给服务器通过“GET”方式提交数据,再返回相应的数据
*
* @param url
* :访问网络的url地址
* @param params
* String url:访问url时,需要传递给服务器的参数。
* 第二个参数格式为: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:实现网络访问文件,先给服务器通过“POST”方式提交数据,再返回相应的数据
*
* @param url
* :访问网络的url地址
* @param params
* String url:访问url时,需要传递给服务器的参数。 第二个参数为: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:实现网络访问文件,先给服务器通过“POST”方式提交数据,再返回相应的数据
*
* @param url
* :访问网络的url地址
* @param params
* String url:访问url时,需要传递给服务器的参数。 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;
}
}