Android HTTP请求方式

Posted 2023-04-03 qq^^614136809

1.HttpClient使用流程
基本流程：

2.HttpClient使用示例
1）使用HttpClient发送GET请求
直接贴下简单的发送Get请求的代码：

public class MainActivity extends Activity implements OnClickListener

private Button btnGet;
private WebView wView;
public static final int SHOW_DATA = 0X123;
private String detail = "";

private Handler handler = new Handler() 
    public void handleMessage(Message msg) 
        if(msg.what == SHOW_DATA)
        
            wView.loadDataWithBaseURL("",detail, "text/html","UTF-8","");
        
    ;
;
@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initView();
    setView();


private void initView() 
    btnGet = (Button) findViewById(R.id.btnGet);
    wView = (WebView) findViewById(R.id.wView);


private void setView() 
    btnGet.setOnClickListener(this);
    wView.getSettings().setDomStorageEnabled(true);

@Override
public void onClick(View v) 
    if (v.getId() == R.id.btnGet) 
        GetByHttpClient();
    

private void GetByHttpClient() 
    new Thread()
    
        public void run() 
        
                try 
                    HttpClient httpClient = new DefaultHttpClient();
                    HttpGet httpGet = new HttpGet("http://www.w3cschool.cc/python/python-tutorial.html");
                    HttpResponse httpResponse = httpClient.execute(httpGet);
                    if (httpResponse.getStatusLine().getStatusCode() == 200) 
                        HttpEntity entity = httpResponse.getEntity();
                        detail = EntityUtils.toString(entity, "utf-8");
                        handler.sendEmptyMessage(SHOW_DATA);
                    
                 catch (Exception e) 
                    e.printStackTrace();
                
        ;
    .start();

运行截图

另外，如果是带有参数的GET请求的话，我们可以将参数放到一个List集合中，再对参数进行URL编码， 最后和URL拼接下就好了：

List params = new LinkedList();
params.add(new BasicNameValuePair(“user”, “猪小弟”));
params.add(new BasicNameValuePair(“pawd”, “123”));
String param = URLEncodedUtils.format(params, “UTF-8”);
HttpGet httpGet = new HttpGet(“http://www.baidu.com”+“?”+param);
2）使用HttpClient发送POST请求
POST请求比GET稍微复杂一点，创建完HttpPost对象后，通过NameValuePair集合来存储等待提交 的参数，并将参数传递到UrlEncodedFormEntity中，最后调用setEntity(entity)完成， HttpClient.execute(HttpPost)即可；这里就不写例子了，暂时没找到Post的网站，又不想 自己写个Servlet，So,直接贴核心代码吧~

核心代码:

private void PostByHttpClient(final String url)

new Thread()

public void run()

try
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
List params = new ArrayList();
params.add(new BasicNameValuePair(“user”, “猪大哥”));
params.add(new BasicNameValuePair(“pawd”, “123”));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params,“UTF-8”);
httpPost.setEntity(entity);
HttpResponse httpResponse = httpClient.execute(httpPost);
if (httpResponse.getStatusLine().getStatusCode() == 200)
HttpEntity entity2 = httpResponse.getEntity();
detail = EntityUtils.toString(entity2, “utf-8”);
handler.sendEmptyMessage(SHOW_DATA);

catch(Exception e)e.printStackTrace();
;
.start();

3.HttpClient抓数据示例(教务系统数据抓取)
其实关于HttpClient的例子有很多，比如笔者曾经用它来抓学校教务系统上学生的课程表: 这就涉及到Cookie，模拟登陆的东西，说到抓数据(爬虫)，一般我们是搭配着JSoup来解析 抓到数据的，有兴趣可以自己查阅相关资料，这里贴下笔者毕设app里获取网页部分的关键 代码！大家可以体会下：

HttpClient可以通过下述代码获取与设置Cookie： HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin); 获得Cookie:cookie = loginResponse.getFirstHeader(“Set-Cookie”).getValue(); 请求时带上Cookie:httpPost.setHeader(“Cookie”, cookie);

//获得链接,模拟登录的实现:
public int getConnect(String user, String key) throws Exception
// 先发送get请求 获取cookie值和__ViewState值
HttpGet getLogin = new HttpGet(true_url);
// 第一步:主要的HTML:
String loginhtml = “”;
HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin);
if (loginResponse.getStatusLine().getStatusCode() == 200)
HttpEntity entity = loginResponse.getEntity();
loginhtml = EntityUtils.toString(entity);
// 获取响应的cookie值
cookie = loginResponse.getFirstHeader(“Set-Cookie”).getValue();
System.out.println("cookie= " + cookie);

// 第二步:模拟登录
// 发送Post请求,禁止重定向
HttpPost httpPost = new HttpPost(true_url);
httpPost.getParams().setParameter(ClientPNames.HANDLE_REDIRECTS, false);

// 设置Post提交的头信息的参数
httpPost.setHeader("User-Agent",
        "Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko");
httpPost.setHeader("Referer", true_url);
httpPost.setHeader("Cookie", cookie);

// 设置请求数据
List<NameValuePair> params = new ArrayList<NameValuePair>();

params.add(new BasicNameValuePair("__VIEWSTATE",
        getViewState(loginhtml)));// __VIEWSTATE参数，如果变化可以动态抓取获取
params.add(new BasicNameValuePair("Button1", ""));
params.add(new BasicNameValuePair("hidPdrs", ""));
params.add(new BasicNameValuePair("hidsc", ""));
params.add(new BasicNameValuePair("lbLanguage", ""));
params.add(new BasicNameValuePair("RadioButtonList1", "%D1%A7%C9%FA"));
params.add(new BasicNameValuePair("txtUserName", user));
params.add(new BasicNameValuePair("TextBox2", key));
params.add(new BasicNameValuePair("txtSecretCode", "")); // ( ╯□╰ )逗比正方,竟然不需要验证码

// 设置编码方式,响应请求,获取响应状态码:
httpPost.setEntity(new UrlEncodedFormEntity(params, "gb2312"));
HttpResponse response = new DefaultHttpClient().execute(httpPost);
int Status = response.getStatusLine().getStatusCode();
if(Status == 200)return Status;
System.out.println("Status= " + Status);

// 重定向状态码为302
if (Status == 302 || Status == 301) 
    // 获取头部信息中Location的值
    location = response.getFirstHeader("Location").getValue();
    System.out.println(location);
    // 第三步:获取管理信息的主页面
    // Get请求
    HttpGet httpGet = new HttpGet(ip_url + location);// 带上location地址访问
    httpGet.setHeader("Referer", true_url);
    httpGet.setHeader("Cookie", cookie);

    // 主页的html
    mainhtml = "";
    HttpResponse httpResponseget = new DefaultHttpClient()
            .execute(httpGet);
    if (httpResponseget.getStatusLine().getStatusCode() == 200) 
        HttpEntity entity = httpResponseget.getEntity();
        mainhtml = EntityUtils.toString(entity);
    


return Status;

4.使用HttpPut发送Put请求
示例代码如下：

public static int PutActCode(String actCode, String licPlate, Context mContext)
int resp = 0;
String cookie = (String) SPUtils.get(mContext, “session”, “”);
HttpPut httpPut = new HttpPut(PUTACKCODE_URL);
httpPut.setHeader(“Cookie”, cookie);
try

    List<NameValuePair> params = new ArrayList<NameValuePair>();
    params.add(new BasicNameValuePair("activation_code", actCode));
    params.add(new BasicNameValuePair("license_plate", licPlate));
    httpPut.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
    HttpResponse course_response = new DefaultHttpClient().execute(httpPut);
    if (course_response.getStatusLine().getStatusCode() == 200) 
        HttpEntity entity2 = course_response.getEntity();
        JSONObject jObject = new JSONObject(EntityUtils.toString(entity2));
        resp = Integer.parseInt(jObject.getString("status_code"));
        return resp;
    
 catch (Exception e) 
    e.printStackTrace();

return resp;

android中Post方式发送HTTP请求

通过Post方式发送HTTP请求的代码逻辑,代码在Eclipse中实现

 

一.主要步骤

1.准备数据装入mydata(一个字节数组)

2.建立连接,设置请求体

HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 

connection.setConnectTimeout(3000);

connection.set...;　　　　　　//设置请求体

connection.connect;

3.通过连接输出数据

OutputStream outputStream = connection.getOutputStream(); 

outputStream.write(mydata,0,mydata.length);

4.通过连接获取服务器返回结果

connection.getInputStream()

 

二.demo 

import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.io.UnsupportedEncodingException; 
import java.net.HttpURLConnection; 
import java.net.MalformedURLException; 
import java.net.URL; 
import java.net.URLEncoder; 
import java.util.HashMap; 
import java.util.Map; 
   
public class HttpUtils { 
   
    private static String PATH = "http://172.24.87.47:8088/myhttp/servlet/LoginAction"; 
    private static URL url; 
    public HttpUtils() {} 
   
    static{ 
        try { 
            url = new URL(PATH); 
        } catch (MalformedURLException e) { 
            e.printStackTrace(); 
        } 
    } 
　　

public static void main(String[] arsg){ 
        Map<String, String> params = new HashMap<String, String>(); 
        params.put("username", "lili"); 
        params.put("password", "123"); 
        String result = sendPostMessage(params,"utf-8"); 
        System.out.println("result->"+result); 
    }

 

/**
     * @param params 填写的url的参数
     * @param encode 字节编码
     * @return
     */ 
    public static String sendPostMessage(Map<String, String> params,String encode){ 
        StringBuffer buffer = new StringBuffer(); 
        try {//把请求的主体写入正文！！ 
             if(params != null&&!params.isEmpty()){ 
                //迭代器 
　　　　　　　　　 //Map.Entry 是Map中的一个接口，他的用途是表示一个映射项（里面有Key和Value）
　　　　　　　　　　　for(Map.Entry<String, String> entry : params.entrySet()){ 
                  buffer.append(entry.getKey()).append("="). 
                  append(URLEncoder.encode(entry.getValue(),encode)). 
                  append("&"); 
              } 
            } 
//            System.out.println(buffer.toString()); 
              //删除最后一个字符&，多了一个;主体设置完毕 
              buffer.deleteCharAt(buffer.length()-1); 
              byte[] mydata = buffer.toString().getBytes();  
              HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 
              connection.setConnectTimeout(3000); 
              connection.setDoInput(true);//表示从服务器获取数据 
              connection.setDoOutput(true);//表示向服务器写数据 
           
             connection.setRequestMethod("POST"); 
              //是否使用缓存 
              connection.setUseCaches(false); 
              //表示设置请求体的类型是文本类型 
              connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); 
                 
              connection.setRequestProperty("Content-Length", String.valueOf(mydata.length)); 
              connection.connect();   //连接，不写也可以。。？？有待了解 
              
              //获得输出流，向服务器输出数据 
              OutputStream outputStream = connection.getOutputStream(); 
                   outputStream.write(mydata,0,mydata.length); 
                   //获得服务器响应的结果和状态码 
              int responseCode = connection.getResponseCode();  
              if(responseCode == HttpURLConnection.HTTP_OK){ 
                 return changeInputeStream(connection.getInputStream(),encode); 
                     
              } 
        } catch (UnsupportedEncodingException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } catch (IOException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
           
        return ""; 
    } 
   /**
    * 将一个输入流转换成字符串
    * @param inputStream
    * @param encode
    * @return
    */ 
    private static String changeInputeStream(InputStream inputStream,String encode) { 
        //通常叫做内存流，写在内存中的 
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); 
        byte[] data = new byte[1024]; 
        int len = 0; 
        String result = ""; 
        if(inputStream != null){ 
            try { 
                while((len = inputStream.read(data))!=-1){ 
                    data.toString(); 
                       
                    outputStream.write(data, 0, len); 
                } 
                //result是在服务器端设置的doPost函数中的 
                result = new String(outputStream.toByteArray(),encode); 
                outputStream.flush(); 
            } catch (IOException e) { 
                // TODO Auto-generated catch block 
                e.printStackTrace(); 
            } 
        } 
        return result; 
    } 
   
}          

 参考文章:https://www.cnblogs.com/jycboy/p/post01.html 　　作者:超超boy