Getting started with Android: Use httpclient to simulate http get and post requests

1. httpclient the description of httpclient is used to simulate HTTP requests. In fact, the essence is to simulate HTTP requests and send them to the Web server;
Android has integrated httpclient, so it can be used directly;
Note: The httpclient Code is applicable not only to Android, but also to General Java programs;
Core http get code:
(1) defaulthttpclient client = new defaulthttpclient (); (2) httpget get = new httpget (string URL); // The URL here is http ://.... /path? Arg1 = Value &.... argn = value (3) httpresponse response = client.exe cute (get); // simulate the request (4) int code = response. getstatusline (). getstatuscode (); // response code (5) inputstream in = response. getentity (). getcontent (); // The data returned by the server

Core http post code:
(1) defaulthttpclient client = new defaulthttpclient (); (2) basicnamevaluepair pair = new basicnamevaluepair (string name, string value); // create a request header field, for example, content-type, text/plain (3) urlencodedformentity entity = new urlencodedformentity (list <namevaluepair> list, string encoding); // perform URL encoding on the custom request header (4) httppost post = new httppost (string URL); // The URL here is http ://.... /path (5) post. setentity (entity); (6) httpresponse response = client.exe cute (post); (7) int code = response. getstatusline (). getstatuscode (); (8) inputstream in = response. getentity (). getcontent (); // The data returned by the server

Ii. server code
The server code and the code that sends the request through urlconnection remain unchanged:

Package Org. xiazdong. servlet; import Java. io. ioexception; import Java. io. outputstream; import javax. servlet. servletexception; import javax. servlet. annotation. webservlet; import javax. servlet. HTTP. httpservlet; import javax. servlet. HTTP. httpservletrequest; import javax. servlet. HTTP. httpservletresponse; @ webservlet ("/servlet1") public class servlet1 extends httpservlet {protected void doget (httpservletrequest Request, httpservletresponse response) throws servletexception, ioexception {string nameparameter = request. getparameter ("name"); string ageparameter = request. getparameter ("Age"); string name = new string (nameparameter. getbytes ("ISO-8859-1"), "UTF-8"); string age = new string (ageparameter. getbytes ("ISO-8859-1"), "UTF-8"); system. out. println ("get"); system. out. println ("name =" + name); system. out. println ("ag E = "+ age); response. setcharacterencoding (" UTF-8 "); outputstream out = response. getoutputstream (); // return data out. Write (" GET request succeeded! ". Getbytes ("UTF-8"); out. close ();} protected void dopost (httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {request. setcharacterencoding ("UTF-8"); string name = request. getparameter ("name"); string age = request. getparameter ("Age"); system. out. println ("Post"); system. out. println ("name =" + name); system. out. println ("age =" + age); response. setcharacterencoding ("UTF-8 "); Outputstream out = response. getoutputstream (); Out. Write (" POST request successful! ". Getbytes (" UTF-8 "); Out. Close ();}}

3. Android client code
The effect is as follows:

Add the following in androidmanifest. xml:

<uses-permission android:name="android.permission.INTERNET"/>  

Mainactivity. Java

Package Org. xiazdong. network. httpclient; import Java. io. bytearrayoutputstream; import Java. io. ioexception; import Java. io. inputstream; import java.net. urlencoder; 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. httpget; import Org. apache. HTTP. client. methods. httppost; import Org. apache. HTTP. impl. client. defaulthttpclient; import Org. apache. HTTP. message. basicnamevaluepair; import android. app. activity; import android. OS. bundle; import android. view. view; import android. view. view. onclicklistener; import android. widget. button; import android. widget. edittext; import android. widget. toast; public class mainactivity extends activity {private edittext Name, age; private button getbutton, postbutton; private onclicklistener listener = new onclicklistener () {@ overridepublic void onclick (view v) {try {If (postbutton = V) {/** namevaluepair indicates a header. List <namevaluepair> stores all the header fields * urlencodedformentity is similar to urlencoder statements for URL encoding * httppost is similar to http post request * client.exe cute () similar to sending a request and returning response */defaulthttpclient client = new defaulthttpclient (); List <namevaluepa IR> List = new arraylist <namevaluepair> (); namevaluepair pair1 = new basicnamevaluepair ("name", name. gettext (). tostring (); namevaluepair pair2 = new basicnamevaluepair ("Age", age. gettext (). tostring (); list. add (pair1); list. add (pair2); urlencodedformentity entity = new urlencodedformentity (list, "UTF-8"); httppost post = new httppost ("http: // 192.168.0.103: 8080/Server/servlet1 "); post. setentity (entity); HT Tpresponse response = client.exe cute (post); If (response. getstatusline (). getstatuscode () = 200) {inputstream in = response. getentity (). getcontent (); // receives data from the server and displays string STR = readstring (in); toast on toast. maketext (mainactivity. this, STR, toast. length_short ). show ();} else toast. maketext (mainactivity. this, "post submission failed", toast. length_short ). show () ;}if (getbutton = V) {defaulthttpclient client = new defaulthttpcl Ient (); stringbuilder Buf = new stringbuilder ("http: // 192.168.0.103: 8080/Server/servlet1"); Buf. append ("? "); Buf. append ("name =" + urlencoder. encode (name. gettext (). tostring (), "UTF-8") + "&"); Buf. append ("age =" + urlencoder. encode (age. gettext (). tostring (), "UTF-8"); httpget get = new httpget (BUF. tostring (); httpresponse response = client.exe cute (get); If (response. getstatusline (). getstatuscode () = 200) {inputstream in = response. getentity (). getcontent (); string STR = readstring (in); toast. maketext (mainactivity. this, S Tr, toast. length_short ). show ();} else toast. maketext (mainactivity. this, "Get submission failed", toast. length_short ). show () ;}} catch (exception e) {}}; @ override public void oncreate (bundle savedinstancestate) {super. oncreate (savedinstancestate); setcontentview (R. layout. main); name = (edittext) This. findviewbyid (R. id. name); age = (edittext) This. findviewbyid (R. id. age); getbutton = (button) This. findviewbyid (R. id. get Button); postbutton = (button) This. findviewbyid (R. id. postbutton); getbutton. setonclicklistener (listener); postbutton. setonclicklistener (listener);} protected string readstring (inputstream in) throws exception {byte [] DATA = new byte [1024]; int length = 0; bytearrayoutputstream bout = new bytearrayoutputstream (); while (length = in. read (data ))! =-1) {bout. Write (data, 0, length);} return new string (bout. tobytearray (), "UTF-8 ");}}