First build a mock Web server, create a new Dynamic Web project, and the servlet code is as follows:
PackageCom.wuyudong.web;Importjava.io.IOException;Importjavax.servlet.ServletException;ImportJavax.servlet.annotation.WebServlet;ImportJavax.servlet.http.HttpServlet;Importjavax.servlet.http.HttpServletRequest;ImportJavax.servlet.http.HttpServletResponse;ImportOrg.apache.catalina.User;/*** Servlet Implementation class Loginservlet*/@WebServlet ("/loginservlet") Public classLoginservletextendsHttpServlet {Private Static Final LongSerialversionuid = 1L; /** * @seeHttpservlet#doget (httpservletrequest request, HttpServletResponse * response)*/ protected voiddoget (httpservletrequest request, httpservletresponse response)throwsservletexception, IOException {String username= Request.getparameter ("username"); String Password= Request.getparameter ("Password"); System.out.println ("User name:" +username); System.out.println ("User name:" +password); if("Wuyudong". Equals (username) && "123". Equals (password)) {Response.getoutputstream (). Write ("Login Success". GetBytes ()); } Else{response.getoutputstream (). Write ("Login Failed". GetBytes ()); } } /** * @seeHttpservlet#dopost (httpservletrequest request, HttpServletResponse * response)*/ protected voidDoPost (httpservletrequest request, httpservletresponse response)throwsservletexception, IOException {//TODO auto-generated Method Stub }}
Create a new JSP page
<%@ Page Language="Java"ContentType="text/html; Charset=utf-8"pageencoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd "><HTML><Head><Metahttp-equiv= "Content-type"content= "text/html; charset=utf-8"><title>Login Page</title></Head><Body> <formAction= "Loginservlet"Method= "Get">User name:<inputname= "username"type= "text"><BR>Password:<inputname= "Password"type= "Password"><BR> <inputtype= "Submit"> </form></Body></HTML>
New Android Project, page layout:
<LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"Xmlns:tools= "Http://schemas.android.com/tools"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent"android:orientation= "vertical"Tools:context=". Mainactivity " > <EditTextAndroid:id= "@+id/et_name"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"Android:hint= "Please enter user name"Android:inputtype= "text" /> <EditTextAndroid:id= "@+id/et_pwd"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"Android:hint= "Please enter password"Android:inputtype= "Textpassword" /> <ButtonAndroid:onclick= "Login"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"Android:text= "Login" /></LinearLayout>
The code is as follows:
Packagecom.wuyudong.loginclient;ImportJava.io.ByteArrayOutputStream;ImportJava.io.InputStream;Importjava.net.HttpURLConnection;ImportJava.net.URL;ImportAndroid.os.Bundle;Importandroid.app.Activity;Importandroid.text.Editable;Importandroid.text.TextUtils;ImportAndroid.view.Menu;ImportAndroid.view.View;ImportAndroid.widget.EditText;ImportAndroid.widget.Toast; Public classMainactivityextendsActivity {PrivateEditText Et_name; PrivateEditText et_pwd; @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate); Setcontentview (R.layout.activity_main); Et_name=(EditText) Findviewbyid (r.id.et_name); Et_pwd=(EditText) Findviewbyid (R.ID.ET_PWD); } Public voidLogin (view view) {String name=Et_name.gettext (). toString (). Trim (); String pwd=Et_pwd.gettext (). toString (). Trim (); if(Textutils.isempty (name) | |Textutils.isempty (PWD)) {Toast.maketext ( This, "User name password cannot be empty", 0). Show (); } Else { //impersonate an HTTP request, submit data to the serverString Path = "Http://169.254.168.71:8080/web/LoginServlet?username=" + name + "&password=" +pwd; Try{URL URL=NewURL (path); //2. Establish an HTTP connectionHttpURLConnection conn =(httpurlconnection) URL. OpenConnection (); //3. Set up some request methodsConn.setrequestmethod ("GET");//Note get word captions must be capitalizedConn.setrequestproperty ("User-agent", "mozilla/5.0 (Windows NT 6.1; WOW64) applewebkit/537.36 (khtml, like Gecko) chrome/45.0.2454.101 safari/537.36 "); intCode = Conn.getresponsecode ();//the server's response code is OK//404 Page Not Found// //503 Server Internal Error if(Code = = 200) {InputStream is=Conn.getinputstream (); //Convert the content of is to a stringBytearrayoutputstream BOS =NewBytearrayoutputstream (); byte[] buffer =New byte[1024]; intLen =-1; while(len = is.read (buffer))! =-1) {bos.write (buffer,0, Len); The String result=NewString (Bos.tobytearray ()); Is.close (); Toast.maketext ( This, result, 0). Show (); } Else{Toast.maketext ( This, "request failed, reason for failure:" + code, 0). Show (); } } Catch(Exception e) {e.printstacktrace (); Toast.maketext ( This, "The request failed, please check the Logcat log console", 0). Show (); } } }}
Add Permission: Android.permission.INTERNET
Error when clicking the button after running the project:
06-18 21:08:16.237:w/system.err (7417): android.os.NetworkOnMainThreadException
Android forcibly lets 4.0 later versions do not check the main thread to access the network.
Workaround, add the following code to the OnCreate:
Strictmode.threadpolicy policy=new StrictMode.ThreadPolicy.Builder (). Permitall (). build ();
Strictmode.setthreadpolicy (Policy);
Get
Android uses get mode to submit data to the server
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