HttpClient之Http请求步骤
apache为客户端http请求提供了一套有用的API,在安卓端编写http请求操作的时候可以使用该API,下面总结一下请求步骤.
壹.创建List<NameValuePair>对象,为表单提供用list存放的参数:
List<NameValuePair> list=getRequestParams(requestParams);
//将请求的Map转换成List
private static List<NameValuePair> getRequestParams(Map<String,String> requestParams){
List<NameValuePair> list=null;
list=new ArrayList<NameValuePair>();
//生成迭代器
Iterator iterator=requestParams.entrySet().iterator();
while (iterator.hasNext()){
//Map.Entry接口,将键值对分隔
Map.Entry<String,String>entry =(Map.Entry<String,String>)iterator.next();
list.add(new BasicNameValuePair(entry.getKey(),entry.getValue()));
}
return list;
}
贰.用singleton模式创建httpclient对象:
HttpClient mHttpClient =SingleTonHttpClients.getInstanceHttpClients();
public class SingleTonHttpClients {
private SingleTonHttpClients(){}
private static final HttpClient mHttpClient=new DefaultHttpClient();
public static HttpClient getInstanceHttpClients(){
return mHttpClient;
}
}
叁.创建HttpPost对象,以post形式提交表单:
HttpPost post=buildHttpPost(list,requestPath);
private static HttpPost buildHttpPost(List<NameValuePair> list,String requestPath){
HttpPost post=null;
try{
UrlEncodedFormEntity postEntity=new UrlEncodedFormEntity(list,"utf-8");
post=new HttpPost(requestPath);
post.setEntity(postEntity);
}
catch (UnsupportedEncodingException e){
e.printStackTrace();
}
return post;
}
肆.执行post方法,请求服务器,返回数据流(创建HttpResponse对象,用以接收服务器返回;HttpEntity对象,用以得到服务器返回内容并以流的形式返回)
InputStream serverInputStream =getSeverResponse(mHttpClient,post)
private static InputStream getSeverResponse(HttpClient mHttpClient,HttpPost post){
try {
HttpResponse mResponse=mHttpClient.execute(post);
HttpEntity mEntity=mResponse.getEntity();
return mEntity.getContent();
}
catch (SocketTimeoutException e){
e.printStackTrace();
}
catch (IOException e){
e.printStackTrace();
}
return null;
}
伍.将输入流读入,并处理成字符串
private static InputStream getSeverResponse(HttpClient mHttpClient,HttpPost post)
private static InputStream getSeverResponse(HttpClient mHttpClient,HttpPost post){
try {
HttpResponse mResponse=mHttpClient.execute(post);
HttpEntity mEntity=mResponse.getEntity();
return mEntity.getContent();
}
catch (SocketTimeoutException e){
e.printStackTrace();
}
catch (IOException e){
e.printStackTrace();
}
return null;
}
完整代码如下:
public class HttpUtils {
/**
*
* @param requestPath 服务器请求路径
* @param requestParams 请求参数
* @param requestEncode 请求表单的编码格式
* @param responseEncode 请求返回体的编码格式
* @return
*/
public static String getResponseString(String requestPath,
Map<String,String>requestParams,String requestEncode,String responseEncode){
//将请求参数转换成list
List<NameValuePair> list=getRequestParams(requestParams);
if(list!=null) {
//创建HttpPost对象,以post形式提交表单
HttpPost post=buildHttpPost(list,requestPath);
//创建httpclient对象
HttpClient mHttpClient =SingleTonHttpClients.getInstanceHttpClients();
if(mHttpClient!=null){
//将服务器返回结果以流的形式读取
InputStream serverInputStream =getSeverResponse(mHttpClient,post);
if (serverInputStream!=null){
//将服务器返回结果转换成字符串
return (getStreamToString(serverInputStream,responseEncode));
}
else {
return "internetexception";
}
}
else {
return "singletonexception";
}
}
else return "paramsexception";
}
/**
* 将请求的Map转换成List
* @param requestParams
* @return
*/
private static List<NameValuePair> getRequestParams(Map<String,String> requestParams){
List<NameValuePair> list=null;
list=new ArrayList<NameValuePair>();
//生成迭代器
Iterator iterator=requestParams.entrySet().iterator();
while (iterator.hasNext()){
//Map.Entry接口,将键值对分隔
Map.Entry<String,String>entry =(Map.Entry<String,String>)iterator.next();
list.add(new BasicNameValuePair(entry.getKey(),entry.getValue()));
}
return list;
}
/**
* 将list放入请求表单中
* 实例化HttpPost对象
* @param list
* @param requestPath
* @return
*/
private static HttpPost buildHttpPost(List<NameValuePair> list,String requestPath){
HttpPost post=null;
try{
UrlEncodedFormEntity postEntity=new UrlEncodedFormEntity(list,"utf-8");
post=new HttpPost(requestPath);
post.setEntity(postEntity);
}
catch (UnsupportedEncodingException e){
e.printStackTrace();
}
return post;
}
/**
* 执行post方法,请求服务器,返回数据流
* @param mHttpClient
* @param post
* @return
*/
private static InputStream getSeverResponse(HttpClient mHttpClient,HttpPost post){
try {
HttpResponse mResponse=mHttpClient.execute(post);
HttpEntity mEntity=mResponse.getEntity();
return mEntity.getContent();
}
catch (SocketTimeoutException e){
e.printStackTrace();
}
catch (IOException e){
e.printStackTrace();
}
return null;
}
/**
* 将网络中的数据流转换成字符串
* @param inputStream
* @param encode
* @return
*/
private static String getStreamToString(InputStream inputStream,String encode){
StringBuffer stringBuffer=new StringBuffer();
try {
BufferedReader mBufferedReader=new BufferedReader(new InputStreamReader(inputStream,encode));
String tmp=new String();
while ((tmp=mBufferedReader.readLine())!=null){
stringBuffer.append(tmp);
}
mBufferedReader.close();
return stringBuffer.toString();
}
catch (UnsupportedEncodingException e){
e.printStackTrace();
return "switchexception";
}
catch (IOException e){
e.printStackTrace();
return "switchexception";
}
}
}
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