android 客户端访问服务器端

android如何实现服务器和客户端的数据传递

我就以我做的一个无线点菜系统为例，服务器端放在pc上，使用tomcat服务器，用servlet写的服务器端，客户端用android。

1.
首先看客户端在客户端我们要发送请求我要得到什么，那么服务器端就看你出的条件了，所谓条件就是参数，你传参数是不传参数，如果不传参数很好办，传参数也好办，哈哈

现在我们看不传参数怎么办，我们把请求的方法全部写在HttpUitl这个类里边

代码如下：

packagecom.Mobile.util;

importjava.io.BufferedReader;

importjava.io.IOException;

importjava.io.InputStreamReader;

importorg.apache.http.HttpEntity;

importorg.apache.http.HttpResponse;

importorg.apache.http.client.ClientProtocolException;

importorg.apache.http.client.HttpClient;

importorg.apache.http.client.methods.HttpGet;

importorg.apache.http.client.methods.HttpPost;

importorg.apache.http.impl.client.DefaultHttpClient;

importorg.apache.http.params.HttpConnectionParams;

importorg.apache.http.params.HttpParams;

importorg.apache.http.util.EntityUtils;

publicclass HttpUtil {

// 基础URL

Public static final StringBASE_URL="http://10.10.120.147:8080/WirelessOrder_Service/";

// 获得Get请求对象request

public static HttpGet getHttpGet(String url){

HttpGet request = new HttpGet(url);

return request;

}

// 获得Post请求对象request

public static HttpPost getHttpPost(String url){

HttpPost request = new HttpPost(url);

return request;

}

// 根据请求获得响应对象response

public static HttpResponsegetHttpResponse(HttpGet request) throws ClientProtocolException, IOException{

HttpResponse response = newDefaultHttpClient().execute(request);

return response;

}

// 根据请求获得响应对象response

public static HttpResponse getHttpResponse(HttpPostrequest) throws ClientProtocolException, IOException{

HttpResponse response = newDefaultHttpClient().execute(request);

return response;

}

// 发送Post请求，获得响应查询结果

public static String queryStringForPost(Stringurl){

// 根据url获得HttpPost对象

HttpPost request =HttpUtil.getHttpPost(url);

String result = null;

try {

// 获得响应对象

HttpResponse response =HttpUtil.getHttpResponse(request);

// 判断是否请求成功

if(response.getStatusLine().getStatusCode()==200){

// 获得响应

result =EntityUtils.toString(response.getEntity());

return result;

}

} catch (ClientProtocolException e) {

e.printStackTrace();

result = "网络异常!";

return result;

} catch (IOException e) {

e.printStackTrace();

result = "网络异常!";

return result;

}

return null;

}

// 获得响应查询结果

public static StringqueryStringForPost(HttpPost request){

String result = null;

try {

// 获得响应对象

HttpResponse response =HttpUtil.getHttpResponse(request);

// 判断是否请求成功

if(response.getStatusLine().getStatusCode()==200){

// 获得响应

result =EntityUtils.toString(response.getEntity());

return result;

}

} catch (ClientProtocolException e) {

e.printStackTrace();

result = "网络异常！";

return result;

} catch (IOException e) {

e.printStackTrace();

result = "网络异常！";

return result;

}

return null;

}

// 发送Get请求，获得响应查询结果

public static
String queryStringForGet(String url){

// 获得HttpGet对象

HttpGet request =HttpUtil.getHttpGet(url);

String result = null;

try {

// 获得响应对象

HttpResponse response =HttpUtil.getHttpResponse(request);

// 判断是否请求成功

if(response.getStatusLine().getStatusCode()==200){

// 获得响应

result =EntityUtils.toString(response.getEntity());

return result;

}

} catch (ClientProtocolException e) {

e.printStackTrace();

result = "网络异常！";

return result;

} catch (IOException e) {

e.printStackTrace();

result = "网络异常！";

return result;

}

return null;

}

//这个方法是用jSON请求获得JSON

public static String getContent(String url)

{

StringBuilder sb=new StringBuilder();

HttpClient client=newDefaultHttpClient();

HttpParamshttpparams=client.getParams();

HttpConnectionParams.setConnectionTimeout(httpparams,3000);

HttpConnectionParams.setSoTimeout(httpparams,5000);

try {

HttpResponseresponse=client.execute(new HttpGet(url));

HttpEntityentity=response.getEntity();

if(entity!=null)

{

BufferedReaderreader=new BufferedReader(new InputStreamReader(entity.getContent(),"utf8"),8192);

String line=null;

while((line=reader.readLine())!=null)

{

sb.append(line+"\n");

}

reader.close();

}

} catch (ClientProtocolException e) {

// TODO Auto-generated catchblock

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catchblock

e.printStackTrace();

}

return sb.toString();

}

}

下面的代码是客户端请求，插入用户信息

ArrayList<NameValuePair>list=new ArrayList<NameValuePair>();

list.add(new BasicNameValuePair("username",us));

list.add(new BasicNameValuePair("password",pw));

list.add(new BasicNameValuePair("name",na));

list.add(new BasicNameValuePair("weight",we));

list.add(new BasicNameValuePair("sex",se));

UrlEncodedFormEntity entity1=null;

try {

entity1=
new UrlEncodedFormEntity(list,HTTP.UTF_8);

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

}

String url=HttpUtil.BASE_URL+"/InsertServlet";

HttpPostrequest = HttpUtil.getHttpPost(url);

下面是用JSON获得订单的例子

String url=HttpUtil.BASE_URL+"/SelectOrderListServlet?"+"orderid="+orde;

String body=HttpUtil.getContent(url);//这个方法在HttpUtil类里边

try {

JSONArray array=new JSONArray(body);

for(int i=0;i<array.length();i++)

{

JSONObject obj=array.getJSONObject(i);

HashMap m=new HashMap<String,Object>();

m.put("name", obj.getString("name"));

m.put("price", obj.getString("price"));

m.put("num",obj.getString("num"));

m.put("menuid",obj.getString("menuid"));

orderlist.add(m);

}

} catch (JSONException e) {

//TODO Auto-generatedcatch block

e.printStackTrace();

}