Android客户端和服务器交互

   Android客户端和服务器交互实现流程：

（客户端输入的用户名和密码提交到服务器端判断后给出相应的操作。）

 

客户端代码：

activity_login.xml

<LinearLayout xmlns: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=".LoginActivity" >    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textColor="#00f"        android:textSize="30px"        android:text="Usrname: " />    <EditText        android:id="@+id/name"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:ems="10" >        <requestFocus />    </EditText>    <TextView        android:id="@+id/textView2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textColor="#00f"        android:textSize="30px"        android:text="Password: " />    <EditText        android:id="@+id/psd"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:ems="10"        android:inputType="textPassword" />    <Button        android:id="@+id/login"        android:layout_width="102dp"        android:layout_height="wrap_content"        android:text=" Login " />    <TextView        android:id="@+id/sign"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="" /></LinearLayout>

 

LoginActivity.java为按钮注册单击事件

login.setOnClickListener(new OnClickListener() {public void onClick(View v) {//单击按钮后发出请求，获取相应结果，并处理。final Handler myHandler =new Handler(){public void handleMessage(Message msg) {String reponse =(String)msg.obj;if(reponse.equals("true")){Intent intent=new Intent(LoginActivity.this,MainActivity.class);startActivity(intent);}else{sign.setText("Username or password incorrect!plz retry.");Toast.makeText(LoginActivity.this,"Username or password incorrect!plz retry.",Toast.LENGTH_LONG);}}};new Thread(new Runnable(){@Overridepublic void run() {LoginToServer logToServer=new LoginToServer();String result=logToServer.doGet(name.getText().toString(), psd.getText().toString());Message msg=new Message();msg.obj=result;//System.out.println(result);myHandler.sendMessage(msg);}}).start();}});

 辅助类LoginToServer.java（通过相应方法连接到服务器并返回状态码）

public class LoginToServer {private String url="http://10.0.2.2:8080/zl/LoginServlet";String result="";public String doGet(String name,String psd){String urlStr=url+"?name="+name+"&psd="+psd;HttpClient hc=new DefaultHttpClient();HttpGet hg=new HttpGet(urlStr);try {HttpResponse resp=hc.execute(hg);//System.out.println(resp.getStatusLine().getStatusCode());if(resp.getStatusLine().getStatusCode()==HttpStatus.SC_OK){HttpEntity he=resp.getEntity();InputStream is=he.getContent();BufferedReader br=new BufferedReader(new InputStreamReader(is));String readLine=null;while((readLine=br.readLine())!=null){result +=readLine;}}else{result="error";}} catch (Exception e) {e.printStackTrace();}return result;}

注意 在AVM中localhost（127.0.0.1）代指的是模拟器本身即手机，要访问本机的Tomcat服务器需用android内置的IP：10.0.2.2

    需要在manifest.xml中配置允许网络访问的权限

 

服务器端代码：

public class LoginServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String name=request.getParameter("name");String psd =request.getParameter("psd");response.setContentType("text/html");PrintWriter out = response.getWriter();//out.println(name);//out.println(psd);//这里判断的是固定的用户名和密码，当然可以数据库中读取if(name.equals("vonzhou") && psd.equals("vonzhou")){out.print(true);}else{out.print(false);}out.flush();out.close();}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doGet(request, response);}}