Android网络框架学习之HttpClient

朱雀 2022-07-12 16:13 232阅读 0赞

### 简介 ###

HttpClient是Apache Jakarta Common下的子项目，用来提供高效的、最新的、功能丰富的支持HTTP协议的客户端编程工具包，并且它支持HTTP协议最新的版本和建议。

### 使用 ###

使用HttpClient发送请求、接收响应很简单，一般需要如下几步即可。  
1. 创建HttpClient对象。  
2. 创建请求方法的实例，并指定请求URL。如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。  
3. 如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。  
4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求，该方法返回一个HttpResponse。  
5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头；调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。  
6. 释放连接。无论执行方法是否成功，都必须释放连接

有些博文使用了 org.apache.commons.httpclient.HttpClient ，有些博文用org.apache.http.client.HttpClient 类。原来，httpclient本来是属于apache-commons 项目下的一个子项目，后来是由Apache HttpComponents项目开发了后面的版本以提供更好的性能和更大的灵活性。commons下的这个httpclient最高版本是目前的3.1，支持HTTP协议1.1，继承了java.net.urlConnection，已经足够提供目前测试的大部分rest服务接口，本文介绍一下用法。这里可以查看所有的API - [http://hc.apache.org/httpclient-3.x/apidocs/overview-summary.html][http_hc.apache.org_httpclient-3.x_apidocs_overview-summary.html]

但是这里注意的是在**Android新版本的API里已经不再集成HttpClient了。不再提供org.apache.http.\***  
**解决方法**  
1.eclipse:  
libs中加入  
org.apache.http.legacy.jar  
上面的jar包在：\*\*\\android-sdk-windows\\platforms\\android-23\\optional下（需要下载android 6.0的SDK）  
2.android studio:  
在相应的module下的build.gradle中加入：  
android \{  
useLibrary ‘org.apache.http.legacy’  
\}注意放置的位置：是在android \{\}中

get方法获取数据

private void HttpClientGet(){
            Log.d(TAG_STRING,"getMethod");
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        String line = null;
                        //用于存储数据结果
                        StringBuffer sb = new StringBuffer();
                        //得到HttpClient对象
                        HttpClient getClient = new DefaultHttpClient();
                        //得到HttpGet对象
                        HttpGet request = new HttpGet(uri);
                        //客户端使用GET方式执行请教，获得服务器端的回应response
                        HttpResponse response = getClient.execute(request);
                        //判断请求是否成功
                        if(response.getStatusLine().getStatusCode()== HttpStatus.SC_OK){
                            Log.d(TAG_STRING, "请求服务器端成功");
                            //注意getEntity方法只能被调用一次，多次调用会报Content has been consumed异常
                            //Log.d(TAG_STRING,EntityUtils.toString(response.getEntity()));
                            //获得输入流
                            InputStream inStrem = response.getEntity().getContent();
    
                            BufferedReader br = new BufferedReader(new InputStreamReader(inStrem));
    
                            while ((line = br.readLine())!=null){
                                sb.append(line);
                            }
                           // Log.d(TAG_STRING,sb.toString());
                            //关闭输入流
                            inStrem.close();
                        }else {
                            Log.d(TAG_STRING, "请求服务器端失败");
                        }
                    } catch (Exception e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }).start();
    
        }

**此处应注意** getEntity方法只能被调用一次，多次调用会报Content has been consumed异常，解决方法是提前在本地创建一个对象把它存储起来。

package com.example.a20256790.httpclientdemo;
    
    
    import android.os.Bundle;
    import android.util.Log;
    
    
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.HttpStatus;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.HttpClient;
    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.impl.client.DefaultHttpClient;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    
    import java.io.BufferedReader;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.ArrayList;
    import java.util.List;
    
    
    import android.app.Activity;
    
    import org.apache.http.HttpVersion;
    
    import org.apache.http.params.BasicHttpParams;
    import org.apache.http.params.HttpConnectionParams;
    import org.apache.http.params.HttpParams;
    import org.apache.http.params.HttpProtocolParams;
    import org.apache.http.protocol.HTTP;
    import java.io.IOException;
    
    
    public class MainActivity extends Activity {
        final String URL_GET = "https://www.baidu.com";
        final String URL_POST = "https://www.baidu.com";
        final String TAG = "zoky";
        final String userName = "zoky";
        final String userPass = "1234";
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            getDataOnInternet();
    
        }
    
    
        private void getDataOnInternet() {
            new Thread(new Runnable() {
                @Override
                public void run() {
                   // doGet(URL_GET);
                    doPost(URL_POST);
                }
            }).start();
        }
    
    
    
        private HttpClient createHttpClient() {
            HttpParams mDefaultHttpParams = new BasicHttpParams();
            //连接超时
            HttpConnectionParams.setConnectionTimeout(mDefaultHttpParams, 15000);
            //请求超时
            HttpConnectionParams.setSoTimeout(mDefaultHttpParams, 15000);
            HttpConnectionParams.setTcpNoDelay(mDefaultHttpParams, true);
            HttpProtocolParams.setVersion(mDefaultHttpParams, HttpVersion.HTTP_1_1);
            HttpProtocolParams.setContentCharset(mDefaultHttpParams, HTTP.UTF_8);
            HttpProtocolParams.setUseExpectContinue(mDefaultHttpParams, true);
            //创建HttpClient客户端
            HttpClient mHttpClient = new DefaultHttpClient(mDefaultHttpParams);
            return mHttpClient;
    
        }
    
        private void doGet(String url) {
            HttpGet mHttpGet = new HttpGet(url);
            mHttpGet.addHeader("Connection", "Keep-Alive");
            try {
                HttpClient mHttpClient = createHttpClient();
                HttpResponse mHttpResponse = mHttpClient.execute(mHttpGet);
                HttpEntity mHttpEntity = mHttpResponse.getEntity();
                int code = mHttpResponse.getStatusLine().getStatusCode();
                if (null != mHttpEntity) {
                    InputStream mInputStream = mHttpEntity.getContent();
                    String respose = InputStreamToString(mInputStream);
                    Log.i(TAG, "StatusCode:" + code + "   result:\n" + respose);
                    mInputStream.close();
                } else {
                    Log.d(TAG,"请求服务器失败");
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        private void doPost(String url) {
            HttpPost mHttpPost = new HttpPost(url);
            mHttpPost.addHeader("Connection", "Keep-Alive");
            try {
                HttpClient mHttpClient = createHttpClient();
                List<NameValuePair> postParams = new ArrayList<>();
                //要传递的参数
                postParams.add(new BasicNameValuePair("username", "moon"));
                postParams.add(new BasicNameValuePair("password", "123"));
                mHttpPost.setEntity(new UrlEncodedFormEntity(postParams));
                HttpResponse mHttpResponse = mHttpClient.execute(mHttpPost);
                HttpEntity mHttpEntity = mHttpResponse.getEntity();
                int code = mHttpResponse.getStatusLine().getStatusCode();
                if (null != mHttpEntity) {
                    InputStream mInputStream = mHttpEntity.getContent();
                    String respose = InputStreamReader(mInputStream);
                    Log.i(TAG, "StatusCode:" + code + "    请求结果:\n" + respose);
                    mInputStream.close();
                } else {
                    Log.d(TAG,"请求服务器失败");
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    
    
        private String InputStreamToString(InputStream is) throws IOException {
            BufferedReader reader = new BufferedReader(new InputStreamReader(is));
            StringBuffer sb = new StringBuffer();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            String respose = sb.toString();
            return respose;
        }
    
    }

返回结果：  
![这里写图片描述][SouthEast]  
以上就是HttpClient的简单使用方法，但是Android官方已经不再推荐用HttpClient进行Android应用的网络通信了，以上很多方法都已经过时，因此，在开发项目时更加推荐使用最新开源的网络框架，如OKHttp、Restrofit等。

参考博客：[采用HttpClient的POST方式、GET方式分别实现登陆案例][HttpClient_POST_GET]

[http_hc.apache.org_httpclient-3.x_apidocs_overview-summary.html]: http://hc.apache.org/httpclient-3.x/apidocs/overview-summary.html
[SouthEast]: /images/20220709/e1214f597e374e3db4fb622351610876.png
[HttpClient_POST_GET]: http://blog.csdn.net/redarmy_chen/article/details/26867699