上一篇专题Android开发之网络请求通信专题（一）：基于HttpURLConnection的请求通信我们讲解了如何使用httpurlconnection来实现基本的文本数据传输。一般在实际开发中我们可以用于传输xml或者json格式的数据。今天我们来讲解另外一种http网络请求的方式:httpclient，并实现文件的上传和下载。
在这里插个题外话，其实这些网络请求有很多第三方jar包可以使用，这些包都封装得很好了。如果只是想使用，我们就直接拿别人得jar包来用就好。博主这里推荐一个叫xutils的工具类，这个玩意其实好用，相信很多人都知道，这个工具类是博主的一个同学的同事写的。后续博主还会写一个图片专题中，也会讲解到xutils里面的图片类的实现原理。好了，进入今天的正题。
和上一篇专题一样，我们先讲解两种请求方式的基本用法，然后再深入进行封装使用。
一、基于httpclient实现文件的上传
我们先看看最基本的上传代码
1、Android端的文件上传
/** * @Title: updateFile * @Description: 文件上传 * @throws */ private void updateFile() { //新建一个httpclient类 HttpClient httpclient = new DefaultHttpClient(); //用post方式实现文件上传 HttpPost post = new HttpPost( "http://192.168.1.107:10010/MINATest/servlet/UploadServlet"); //拿到上传的图片 String filePath = Environment.getExternalStorageDirectory() .getAbsolutePath() + "/justice.jpg"; //处理上传的文件 FileBody fileBody = new FileBody(new File(filePath)); StringBody stringBody = null; try { stringBody = new StringBody("文件的描述"); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } MultipartEntity entity = new MultipartEntity(); entity.addPart("file", fileBody); entity.addPart("desc", stringBody); post.setEntity(entity); HttpResponse response = null; try { response = httpclient.execute(post); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) { //拿到返回的实体，一般而言，用post请求方式返回的流是用这个实体拿到，在这里不需要所以博主就不写了。 HttpEntity entitys = response.getEntity(); if (entity != null) { System.out.println(entity.getContentLength()); try { System.out.println(EntityUtils.toString(entitys)); } catch (ParseException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } httpclient.getConnectionManager().shutdown(); }2、服务端dopost处理
/** * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */ @Override public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { boolean isMulti = ServletFileUpload.isMultipartContent(request); if (isMulti) { String realPath = request.getSession().getServletContext() .getRealPath("/vioce"); System.out.println(realPath); File dir = new File(realPath); if (!dir.exists()) { dir.mkdirs(); } FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); upload.setHeaderEncoding("UTF-8"); String fileName = null; try { List<FileItem> items = upload.parseRequest(request); for (FileItem item : items) { if (item.isFormField()) { String name = item.getFieldName(); String value = item.getString("UTF-8"); System.out.println(name + "-" + value); } else { item.write(new File(dir, item.getName())); fileName = item.getName(); } } response.setContentType("text/*;charset=utf-8"); response.getWriter().write("上传成功"); } catch (Exception e) { e.printStackTrace(); } } }我们可以看到当执行了上传方法之后，在服务端指定的文件夹中已经有了从android端上传过来的图片，而android端的logcat中也打印出了服务端返回的上传成功的字样。3、Android端文件的下载
这里博主省事了，直接将地址写死。
/** * @Title: downLoadFile * @Description:文件下载 * @throws */ private void downLoadFile() { HttpClient httpClient1 = new DefaultHttpClient(); HttpGet httpGet1 = new HttpGet( "http://192.168.31.144:10010/MINATest/vioce/strikefreedom.jpg"); try { HttpResponse httpResponse1 = httpClient1.execute(httpGet1); StatusLine statusLine = httpResponse1.getStatusLine(); if (statusLine.getStatusCode() == 200) { String filePath = Environment.getExternalStorageDirectory() .getAbsolutePath() + "/freedom.jpg"; // 文件路径 File file = new File(filePath); FileOutputStream outputStream = new FileOutputStream(file); InputStream inputStream = httpResponse1.getEntity() .getContent(); byte b[] = new byte[1024]; int j = 0; while ((j = inputStream.read(b)) != -1) { outputStream.write(b, 0, j); } outputStream.flush(); outputStream.close(); } } catch (Exception e) { e.printStackTrace(); } finally { httpClient1.getConnectionManager().shutdown(); } }二、httpclient类的封装
1、封装逻辑
虽然HttPclient相对于httpurlconnection已经有了一定的封装，api也相对简洁一些，但是我们还是可以再这个基础上再进行一次封装。封装结构和上一篇差不多。上一篇专题中，我们用了四个类去封装。这里我们用android里的AsyncTask类来替代handler，也可以省去一个回调的监听。这里回调接口的设计其实根据需求自己去设定就好，博主就拿之前的一个回调接口来用。这次我们需要三个类
1、http访问管理者
2、任务AsyncTask类
3、http访问结果事件处理回调接口。
整个逻辑关系为：http访问管理者采用get或者post请求方式请求，当产生结果后监听器告诉消息通信管理者应该发送什么消息给UI线程，UI线程更具消息通信管理者发送过来的消息，调用对应的事件处理回调接口。
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接下来我们来一一对应这三个类的编写
2、http访问管理者
package com.example.nettest;import java.io.IOException;import java.io.InputStream;import java.io.UnsupportedEncodingException;import java.util.ArrayList;import java.util.List;import org.apache.commons.lang.StringUtils;import org.apache.http.HttpHost;import org.apache.http.HttpRequest;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.CookieStore;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.conn.params.ConnRoutePNames;import org.apache.http.entity.ByteArrayEntity;import org.apache.http.entity.StringEntity;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.message.BasicNameValuePair;import org.apache.http.params.BasicHttpParams;import org.apache.http.params.HttpConnectionParams;import org.apache.http.params.HttpParams;import com.lidroid.xutils.http.client.multipart.MultipartEntity;/** * @ClassName: FreedomHttpClientUtil * @author victor_freedom ([email protected]) * @createddate 2015-1-25 下午11:04:59 * @Description: */public class FreedomHttpClientUtil { private DefaultHttpClient client; /** 请求接口 */ private HttpRequest httpRequest; /** 响应接口 */ private HttpResponse response; /** 方法 */ private String mMethod; public static final String POST = "post"; public static final String GET = "get"; private static final String TAG = "FreedomHttpClientUtil"; public static final int HTTP_OK = 200; private void open() { HttpParams params = new BasicHttpParams(); HttpConnectionParams.setConnectionTimeout(params, 5000); // 设置连接超时 HttpConnectionParams.setSoTimeout(params, 5000); // 设置请求超时 client = new DefaultHttpClient(params); try { // 如果不是wifi，我们需要设定一下手机的APN参数 if (StringUtils.isNotBlank(ConfigParams.PROXY)) { HttpHost proxy = new HttpHost(ConfigParams.PROXY, ConfigParams.PORT); client.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy); } // 默认使用UTF-8编码 httpRequest.setHeader("Charset", "UTF-8"); } catch (Exception e) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } } /** * 可以同时处理post与get两种形式请求 * * @param url * @param method */ public void open(String url, String method) { if (StringUtils.isNotBlank(method) && StringUtils.isNotBlank(url)) { if (method.equals(POST)) { httpRequest = new HttpPost(url); mMethod = POST; } else { httpRequest = new HttpGet(url); mMethod = GET; } open(); } } /** * @Title: setHttpPostHeader * @Description: 设置请求头 * @param name * @param value * @throws */ public void setHttpPostHeader(String name, String value) { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (StringUtils.isNotBlank(name)) { httpRequest.setHeader(name, value); } } /** * @Title: setContent * @Description:设置字节类型实体 * @param info * @throws */ public void setContent(byte[] info) { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (info.length > 0) { ByteArrayEntity entity = new ByteArrayEntity(info); if (httpRequest instanceof HttpPost) ((HttpPost) httpRequest).setEntity(entity); } } /** * @Title: setStringEntity * @Description: 设置字符串型实体 * @param datas * @throws */ public void setStringEntity(String datas) { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (null != datas) { try { StringEntity entity = new StringEntity(datas); if (httpRequest instanceof HttpPost) ((HttpPost) httpRequest).setEntity(entity); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } } /** * @Title: setJsonStringEntity * @Description: 设置json数据格式实体 * @param datas * @throws */ public void setJsonStringEntity(String datas) { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (null != datas) { try { StringEntity entity = new StringEntity(datas, "utf-8"); entity.setContentType("application/json"); // entity.setContentEncoding("utf-8"); if (httpRequest instanceof HttpPost) ((HttpPost) httpRequest).setEntity(entity); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } } /** * @Title: setEntitys * @Description: 设置多参数实体 * @param datas * @throws */ public void setEntitys(String... datas) { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (datas.length > 0) { List<NameValuePair> Parameters = new ArrayList<NameValuePair>(); for (int i = 0; i < datas.length; i += 2) { Parameters.add(new BasicNameValuePair(datas[i], datas[i + 1])); } if (httpRequest instanceof HttpPost) try { ((HttpPost) httpRequest) .setEntity(new UrlEncodedFormEntity(Parameters, "UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } } /** * @Title: setDataEntitys * @Description: 设置数据实体 * @param mpEntity * @throws */ public void setDataEntitys(MultipartEntity mpEntity) { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (httpRequest instanceof HttpPost) { ((HttpPost) httpRequest).setEntity(mpEntity); } } /** * @Title: post * @Description: 发送请求 * @throws Exception * @throws */ public void post() throws Exception { if (httpRequest == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } if (mMethod.equals(POST)) { response = client.execute((HttpPost) httpRequest); } else { response = client.execute((HttpGet) httpRequest); } } /** * @Title: getContentLength * @Description:拿到返回内容长度 * @return * @throws */ public long getContentLength() { long result = 0; if (response == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } result = response.getEntity().getContentLength(); return result; } /** * @Title: openInputStream * @Description: 拿到返回流 * @return * @throws IllegalStateException * @throws IOException * @throws */ public InputStream openInputStream() throws IllegalStateException, IOException { if (response == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } InputStream result = response.getEntity().getContent(); return result; } /** * @Title: getCookieStore * @Description: 拿到cookie * @return * @throws */ public CookieStore getCookieStore() { if (null == client) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } return client.getCookieStore(); } /** * @Title: getResponseCode * @Description:拿到返回码 * @return * @throws */ public int getResponseCode() { int result; if (response == null) { throw new FreedomException(FreedomException.NETWORK_ANOMALY); } result = response.getStatusLine().getStatusCode(); return result; } /** * @Title: setRequestProperty * @Description: 设置请求头 * @param name * @param value * @throws */ public void setRequestProperty(String name, String value) { setHttpPostHeader(name, value); } /** * @ClassName: ConfigParams * @author victor_freedom ([email protected]) * @createddate 2015-1-25 下午11:11:05 * @Description:如果不是WIFI访问，需要设置的参数 */ public static class ConfigParams { public static String SRC = ""; public static String PROXY = ""; public static int PORT; public static String TYPE = ""; public static String MNC = ""; }}
2、任务AsyncTask类
这类的编写，需要根据实际的业务需求来设定三个参数，相信了解AsyncTask类的同学都清楚如何使用这个类。不了解的同学也可以百度一下，网上有很多相关的文章。这里我们以下载文件的例子来说明
package com.example.nettest;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;import android.annotation.SuppressLint;import android.app.ProgressDialog;import android.content.Context;import android.os.AsyncTask;import android.os.Environment;/** * @ClassName: FreedomAsynTask * @author victor_freedom ([email protected]) * @createddate 2014年10月12日 下午10:07:36 * @Description: TODO * */public class FreedomAsynTask extends AsyncTask<Void, Integer, String> { private FreedomHttpCallBackListener listener; public FreedomAsynTask(FreedomHttpCallBackListener listener, Context context, ProgressDialog mDialog, String path) { this.listener = listener; } @SuppressLint("DefaultLocale") @Override protected String doInBackground(Void... params) { InputStream is = null; FreedomHttpClientUtil http = new FreedomHttpClientUtil(); http.open( "http://192.168.31.144:10010/MINATest/vioce/strikefreedom.jpg", FreedomHttpClientUtil.GET); try { http.post(); if (http.getResponseCode() == 200) { String filePath = Environment.getExternalStorageDirectory() .getAbsolutePath() + "/freedom.jpg"; // 文件路径 File file = new File(filePath); FileOutputStream outputStream = new FileOutputStream(file); InputStream inputStream = http.openInputStream(); byte b[] = new byte[1024]; int j = 0; while ((j = inputStream.read(b)) != -1) { outputStream.write(b, 0, j); } outputStream.flush(); outputStream.close(); return "下载成功"; } else { return null; } } catch (Exception e) { e.printStackTrace(); return null; } } @Override protected void onProgressUpdate(Integer... values) { super.onProgressUpdate(values); } @Override protected void onPreExecute() { super.onPreExecute(); } @Override protected void onPostExecute(String result) { if (null != result) { listener.action(FreedomHttpCallBackListener.EVENT_GET_DATA_SUCCESS, result); } else { listener.action(FreedomHttpCallBackListener.EVENT_GET_DATA_EEEOR, null); } super.onPostExecute(result); }}我们可以看到，在不同的返回结果里面，action里对应传入了不同的参数。这里的监听封装博主就偷懒了，直接这么写，想要更完善完美一点其实应该可以做的更好。有兴趣的同学可以去完善，博主就偷懒了。关于监听类上一篇文章已经讲过，这里就不在详细描述我们来看activity中的使用
3、Activity中的使用
使用起来非常的简单，我们只需要一行代码就实现了文件的下载
if (NetUtils.checkNetWork(mContext)) { new FreedomAsynTask(new FreedomHttpCallBackListener() { @Override public void action(int code, Object obj) { //根据返回code判断执行方法 } }).execute(); }好了，第二篇关于http访问的文章已经讲解完毕，希望能够帮助到看到此文的人。