Get请求和Post请求的区别

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首先我们先了解下Get请求和Post请求的区别:

表单提交中get和 post方式的区别有5点:
1.get是从服务器上获取数据,post是向服务器传送数据。
2.get是把参数数据队列加到提交表单的 ACTION属性所指的URL中,值和表单内各个字段一一对应,在URL中可以看到。post是通过HTTPpost机制,将表单内各个字段与其内容放置在HTML HEADER内一起传送到ACTION属性所指的URL地址。用户看不到这个过程。
3.对于get方式,服务器端用 Request.QueryString获取变量的值,对于post方式,服务器端用Request.Form获取提交的数据。
4.get 传送的数据量较小,不能大于2KB。post传送的数据量较大,一般被默认为不受限制。但理论上,IIS4中最大量为80KB,IIS5中为100KB。
5.get安全性非常低,post安全性较高。

一、HttpClient方式

1、HTTP GET 示例:

 public class TestHttpGetMethod{        public void get(){           BufferedReader in = null;           try{                HttpClient client = new DefaultHttpClient();                HttpGet request = new HttpGet();                request.setURI("http://w26.javaeye.com");                HttpResponse response = client.execute(request);                 in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));                  StringBuffer sb = new StringBuffer("");                String line = "";              String NL = System.getProperty("line.separator");               while((line = in.readLine()) != null){                   sb.append(line + NL);               }               in.close();              String page = sb.toString();               Log.i(TAG, page);           }catch(Exception e){               Log.e(TAG,e.toString())           }finally{               if(in != null){                   try{                       in.close();                   }catch(IOException ioe){                      Log.e(TAG, ioe.toString());                   }               }           }       }   }

带参数的 HTTP GET: 
HttpGet request = new HttpGet("http://www.baidu.com/s?wd=amos_tl");  
client.execute(request);

2、HTTP POST 示例:

 public class TestHttpPostMethod{       public void post(){           BufferedReader in = null;           try{               HttpClient client = new DefaultHttpClient();               HttpPost request = new HttpPost("http://localhost/upload.jsp");                List<NameValuePair> postParams = new ArrayList<NameValuePair>();                postParams.add(new BasicNameValuePair("filename", "sex.mov"));               UrlEncodeFormEntity formEntity = new UrlEncodeFormEntity(postParams);               request.setEntity(formEntity);               HttpResponse response = client.execute(request);              in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));                  StringBuffer sb = new StringBuffer("");                String line = "";              String NL = System.getProperty("line.separator");               while((line = in.readLine()) != null){                  sb.append(line + NL);               }               in.close();               String result = sb.toString();              Log.i(TAG, result );           }catch(Exception e){              Log.e(TAG,e.toString())           }finally{               if(in != null){                  try{                       in.close();                   }catch(IOException ioe){                       Log.e(TAG, ioe.toString());                   }               }           }       }  }









二、HttpURLConnection 方式

  URL url = null;  HttpURLConnection conn = null;  InputStream in = null;  OutputStream out = null;  byte[] data ="测试字符串".getBytes();  try{     url =new URL("www.xxx.com/servlet");   conn = (HttpURLConnection) url.openConnection();     //设置连接属性    conn.setDoOutput(true);// 使用 URL 连接进行输出    conn.setDoInput(true);// 使用 URL 连接进行输入    conn.setUseCaches(false);// 忽略缓存    conn.setConnectTimeout(30000);//设置连接超时时长,单位毫秒    conn.setRequestMethod("POST");//设置请求方式,POST or GET,注意:如果请求地址为一个servlet地址的话必须设置成POST方式  //设置请求头   conn.setRequestProperty("Accept", "*/*");   conn.setRequestProperty("Connection", "Keep-Alive");   conn.setRequestProperty("Accept-Charset", "utf-8");   if (data != null) {      out = conn.getOutputStream();      out.write(data);   }   int code = conn.getResponseCode();   if(code ==200){     in = conn.getInputStream();// 可能造成阻塞      long len = conn.getContentLength();      byte[] bs = new byte[(int) len];//返回结果字节数组     int all = 0;   int dn = 0;      while ((dn = in.read(bs, all, 1)) > 0) {        all += dn;        if (all == len) {        break;        }      }   } }



那么接下来让我们看看在Android平台开发中如何执行一个Post请求:

以下是代码示例:

 package com.jindegege.search;  import java.util.ArrayList;  import java.util.List;  import org.apache.http.HttpResponse;  import org.apache.http.NameValuePair;  import org.apache.http.client.entity.UrlEncodedFormEntity;  import org.apache.http.client.methods.HttpPost;  import org.apache.http.impl.client.DefaultHttpClient;  import org.apache.http.message.BasicNameValuePair;  import org.apache.http.protocol.HTTP;  import org.apache.http.util.EntityUtils;  import android.app.Activity;  import android.os.Bundle;  import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class mian extends Activity {         /** Called when the activity is first created. */         private Button btnTest;        @Override         public void onCreate(Bundle savedInstanceState) {                 super.onCreate(savedInstanceState);                setContentView(R.layout.main);                 btnTest = (Button) findViewById(R.id.Button01);                 btnTest.setOnClickListener(new OnClickListener() {                         @Override                         public void onClick(View v) {                                 getWeather();                         }
                 });         }         private void getWeather(){                 try {                        final String SERVER_URL = "http://webservice.webxml.com.cn/WebServices/WeatherWS.asmx/getWeather"; // 定义需要获取的内容来源地址                        HttpPost request = new HttpPost(SERVER_URL); // 根据内容来源地址创建一个Http请求                        List params = new ArrayList();                        params.add(new BasicNameValuePair("theCityCode", "长沙")); // 添加必须的参数                         params.add(new BasicNameValuePair("theUserID", "")); // 添加必须的参数                         request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8)); // 设置参数的编码                         HttpResponse httpResponse = new DefaultHttpClient().execute(request); // 发送请求并获取反馈 // 解析返回的内容                         if (httpResponse.getStatusLine().getStatusCode() != 404)                         {                                 String result = EntityUtils.toString(httpResponse.getEntity());                                 System.out.println(result);                         }                 } catch (Exception e) {                 }         } }




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