引子

try?{
????????//?创建一个默认的HttpClient
????????HttpClient?httpclient?=new?DefaultHttpClient();
????????//?创建一个GET请求
????????HttpGet?request?=new?HttpGet("www.google.com");
????????//?发送GET请求，并将响应内容转换成字符串
????????String?response?=?httpclient.execute(request,?new?BasicResponseHandler());
????????Log.v("response?text",?response);
????}?catch?(ClientProtocolException?e)?{
????????e.printStackTrace();
????}?catch?(IOException?e)?{
????????e.printStackTrace();
????}

为什么要使用单例HttpClient？

HttpClient?httpclient?=new?DefaultHttpClient();

publicclass?CustomerHttpClient?{
????privatestatic?HttpClient?customerHttpClient;
????
????private?CustomerHttpClient()?{
????}
????
????publicstatic?HttpClient?getHttpClient()?{
????????if(null==?customerHttpClient)?{
????????????customerHttpClient?=new?DefaultHttpClient();
????????}
????????return?customerHttpClient;
????}
}

public?class?CustomerHttpClient?{
????private?staticfinal?String?CHARSET?=?HTTP.UTF_8;
????private?static?HttpClient?customerHttpClient;

????private?CustomerHttpClient()?{
????}

????public?static?synchronized?HttpClient?getHttpClient()?{
????????if?(null==?customerHttpClient)?{
????????????HttpParams?params?=new?BasicHttpParams();
????????????//?设置一些基本参数
????????????HttpProtocolParams.setVersion(params,?HttpVersion.HTTP_1_1);
????????????HttpProtocolParams.setContentCharset(params,????????????????????CHARSET);
????????????HttpProtocolParams.setUseExpectContinue(params,?true);
????????????HttpProtocolParams
????????????????????.setUserAgent(
????????????????????????????params,????????????????????????????"Mozilla/5.0(Linux;U;Android?2.2.1;en-us;Nexus?One?Build.FRG83)?"
????????????????????????????????????+"AppleWebKit/553.1(KHTML,like?Gecko)?Version/4.0?Mobile?Safari/533.1");
????????????//?超时设置
/*?从连接池中取连接的超时时间?*/
????????????ConnManagerParams.setTimeout(params,?1000);
????????????/*?连接超时?*/
????????????HttpConnectionParams.setConnectionTimeout(params,?2000);
????????????/*?请求超时?*/
????????????HttpConnectionParams.setSoTimeout(params,?4000);
????????????
????????????//?设置我们的HttpClient支持HTTP和HTTPS两种模式
????????????SchemeRegistry?schReg?=new?SchemeRegistry();
????????????schReg.register(new?Scheme("http",?PlainSocketFactory
????????????????????.getSocketFactory(),?80));
????????????schReg.register(new?Scheme("https",?SSLSocketFactory
????????????????????.getSocketFactory(),?443));

????????????//?使用线程安全的连接管理来创建HttpClient
????????????ClientConnectionManager?conMgr?=new?ThreadSafeClientConnManager(
????????????????????params,?schReg);
????????????customerHttpClient?=new?DefaultHttpClient(conMgr,?params);
????????}
????????return?customerHttpClient;
????}
}

HttpClient的3种超时说明

/*?从连接池中取连接的超时时间?*/
ConnManagerParams.setTimeout(params,?1000);
/*?连接超时?*/
HttpConnectionParams.setConnectionTimeout(params,?2000);
/*?请求超时?*/
HttpConnectionParams.setSoTimeout(params,?4000);

封装简单的POST请求

privatestaticfinal?String?TAG?="CustomerHttpClient";

publicstatic?String?post(String?url,?NameValuePair...?params)?{
????????try?{
????????????//?编码参数
????????????List<NameValuePair>?formparams?=new?ArrayList<NameValuePair>();?//?请求参数
for?(NameValuePair?p?:?params)?{
????????????????formparams.add(p);
????????????}
????????????UrlEncodedFormEntity?entity?=new?UrlEncodedFormEntity(formparams,????????????????????CHARSET);
????????????//?创建POST请求
????????????HttpPost?request?=new?HttpPost(url);
????????????request.setEntity(entity);
????????????//?发送请求
????????????HttpClient?client?=?getHttpClient();
????????????HttpResponse?response?=?client.execute(request);
????????????if(response.getStatusLine().getStatusCode()?!=?HttpStatus.SC_OK)?{
????????????????thrownew?RuntimeException("请求失败");
????????????}
????????????HttpEntity?resEntity?=??response.getEntity();
????????????return?(resEntity?==null)??null?:?EntityUtils.toString(resEntity,?CHARSET);
????????}?catch?(UnsupportedEncodingException?e)?{
????????????Log.w(TAG,?e.getMessage());
????????????returnnull;
????????}?catch?(ClientProtocolException?e)?{
????????????Log.w(TAG,?e.getMessage());
????????????returnnull;
????????}?catch?(IOException?e)?{
????????????thrownew?RuntimeException("连接失败",?e);
????????}

????}

使用我们的CustomerHttpClient工具类

final?String?url?="http://yourdomain/context/adduser";
????//准备数据
????NameValuePair?param1?=new?BasicNameValuePair("username",?"张三");
????NameValuePair?param2?=new?BasicNameValuePair("password",?"123456");
????int?resultId?=-1;
????try?{
????????//?使用工具类直接发出POST请求,服务器返回json数据，比如"{userid:12}"
????????String?response?=?CustomerHttpClient.post(url,?param1,?param2);
????????JSONObject?root?=new?JSONObject(response);
????????resultId?=?Integer.parseInt(root.getString("userid"));
????????Log.i(TAG,?"新用户ID："+?resultId);
????}?catch?(RuntimeException?e)?{
????????//?请求失败或者连接失败
????????Log.w(TAG,?e.getMessage());
????????Toast.makeText(this,?e.getMessage(),?Toast.LENGTH_SHORT);
????}?catch?(Exception?e)?{
????????//?JSon解析出错
????????Log.w(TAG,?e.getMessage());
????}

结语