編輯:關於Android編程
Android網絡編程之傳遞數據給服務器(一)
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因為Android程序需要和服務器進行通信,所以需要服務器端提供的支持。
通過GET方式上傳數據主要適用於數據大小不超過2KB,且對安全性要求不高的情況下。
服務器端項目結構:
package com.jph.sgm.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class ServletForGETMethod */ @WebServlet("/ServletForGETMethod") public class ServletForGETMethod extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ServletForGETMethod() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //獲取請求的參數(使用utf-8進行解碼,然後用進行ISO8859-1編碼) // String name=new String(request.getParameter("name").getBytes("ISO8859-1"),"utf-8"); String name=request.getParameter("name"); String pwd=request.getParameter("pwd"); System.out.println("name:"+name+" pwd:"+pwd); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub } }
發布項目並在浏覽器中輸入:http://localhost:8080/ServerForGETMethod/ServletForGETMethod?name=aa&pwd=124
可以再控制台看到如下圖的輸出:
至此服務器端項目已經完成。下面開始創建Android端項目。
Android端項目結構:
核心代碼:SendDateToServer.java:
package com.jph.sdg.service; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLEncoder; import java.util.HashMap; import java.util.Map; import android.os.Handler; /** * 通過GET方式向服務器發送數據 * @author jph * Date:2014.09.27 */ public class SendDateToServer { private static String url="http://10.219.61.117:8080/ServerForGETMethod/ServletForGETMethod"; public static final int SEND_SUCCESS=0x123; public static final int SEND_FAIL=0x124; private Handler handler; public SendDateToServer(Handler handler) { // TODO Auto-generated constructor stub this.handler=handler; } /** * 通過Get方式向服務器發送數據 * @param name 用戶名 * @param pwd 密碼 */ public void SendDataToServer(String name,String pwd) { // TODO Auto-generated method stub final Mapmap=new HashMap (); map.put("name", name); map.put("pwd", pwd); new Thread(new Runnable() { @Override public void run() { // TODO Auto-generated method stub try { if (sendGetRequest(map,url,"utf-8")) { handler.sendEmptyMessage(SEND_SUCCESS);//通知主線程數據發送成功 }else { //將數據發送給服務器失敗 } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } }).start(); } /** * 發送GET請求 * @param map 請求參數 * @param url 請求路徑 * @return * @throws Exception */ private boolean sendGetRequest(Map param, String url,String encoding) throws Exception { // TODO Auto-generated method stub //http://localhost:8080/ServerForGETMethod/ServletForGETMethod?name=aa&pwd=124 StringBuffer sb=new StringBuffer(url); if (!url.equals("")&!param.isEmpty()) { sb.append("?"); for (Map.Entry entry:param.entrySet()) { sb.append(entry.getKey()+"="); sb.append(URLEncoder.encode(entry.getValue(), encoding)); sb.append("&"); } sb.deleteCharAt(sb.length()-1);//刪除字符串最後 一個字符“&” } HttpURLConnection conn=(HttpURLConnection) new URL(sb.toString()).openConnection(); conn.setConnectTimeout(5000); conn.setRequestMethod("GET");//設置請求方式為GET if (conn.getResponseCode()==200) { return true; } return false; } }
package com.jph.sdg.activity; import com.jph.sdg.R; import com.jph.sdg.service.SendDateToServer; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.app.Activity; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; /** * 通過GET方式向服務器發送數據,通過GET方式上傳數據主要適用於數 * 據大小不超過2KB,且對安全性要求不高的情況下。 * @author jph * Date:2014.09.27 */ public class MainActivity extends Activity { private EditText edtName,edtPwd; private Button btnSend; Handler handler=new Handler(){ public void handleMessage(Message msg) { switch (msg.what) { case SendDateToServer.SEND_SUCCESS: Toast.makeText(MainActivity.this, "登陸成功", Toast.LENGTH_SHORT).show(); break; case SendDateToServer.SEND_FAIL: Toast.makeText(MainActivity.this, "登陸失敗", Toast.LENGTH_SHORT).show(); break; default: break; } }; }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); edtName=(EditText)findViewById(R.id.edtName); edtPwd=(EditText)findViewById(R.id.edtPwd); btnSend=(Button)findViewById(R.id.btnSend); btnSend.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub String name=edtName.getText().toString(); String pwd=edtPwd.getText().toString(); if (edtName.equals("")||edtPwd.equals("")) { Toast.makeText(MainActivity.this, "用戶名或密碼不能為空", Toast.LENGTH_LONG).show(); }else { new SendDateToServer(handler).SendDataToServer(name, pwd); } } }); } }
至此Android端項目已經完成了。下面就讓我們看一下APP運行效果吧:
Android運行效果圖:
2
當客戶端向服務器發送中文時服務器端會出現亂碼現象,如下圖:
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出現亂碼的原因主要是,Android客戶端我們采用的是UTF-8編碼,而Tomcat默認采用的是ISO8858-1編碼,所以會出現中文亂碼的現象。
解決方案有兩種:
是使用UTF-8解碼請求參數得到漢字,然後再通過ISO8859-1進行編碼。此時服務器端的Servlet是:
package com.jph.sgm.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class ServletForGETMethod */ @WebServlet("/ServletForGETMethod") public class ServletForGETMethod extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ServletForGETMethod() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //獲取請求的參數(使用utf-8進行解碼,然後用進行ISO8859-1編碼) String name=new String(request.getParameter("name").getBytes("ISO8859-1"),"utf-8"); // String name=request.getParameter("name"); String pwd=request.getParameter("pwd"); System.out.println("name:"+name+" pwd:"+pwd); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub } }
運行結果如下圖:
下面我們采用過濾器的方式來解決亂碼的問題:
第一步:建立一個Filter過濾器。
EncodingFilter.java
package com.jph.sgm.filter; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebFilter; import javax.servlet.http.HttpServletRequest; /** * Servlet Filter implementation class EncodingFilter */ @WebFilter("/*") public class EncodingFilter implements Filter { /** * Default constructor. */ public EncodingFilter() { // TODO Auto-generated constructor stub } /** * @see Filter#destroy() */ public void destroy() { // TODO Auto-generated method stub } /** * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain) */ public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { // TODO Auto-generated method stub HttpServletRequest req=(HttpServletRequest) request; if ("GET".equals(req.getMethod())) { HttpServletRequestEncodingWrapper wrapper=new HttpServletRequestEncodingWrapper(req); chain.doFilter(wrapper, response); }else { req.setCharacterEncoding("utf-8"); chain.doFilter(request, response); } } /** * @see Filter#init(FilterConfig) */ public void init(FilterConfig fConfig) throws ServletException { // TODO Auto-generated method stub } }
上面的過濾器因為設置了過濾路徑為*/所以會過濾所有的Servlet。
在上面的過濾器中用到了一個包裝器,HttpServletRequestEncodingWrapper.java
package com.jph.sgm.filter; import java.io.UnsupportedEncodingException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; public class HttpServletRequestEncodingWrapper extends HttpServletRequestWrapper { private HttpServletRequest request; public HttpServletRequestEncodingWrapper(HttpServletRequest request) { // TODO Auto-generated constructor stub super(request); this.request=request; } @Override public String getParameter(String name) { // TODO Auto-generated method stub String value=request.getParameter(name); if (value!=null) { try {//用utf-8進行解碼,然後用ISO8859-1進行編碼 return new String(value.getBytes("ISO8859-1"),"utf-8"); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return super.getParameter(name); } }
重新運行項目可以看到服務器會將客戶端發來的數據用UTF-8進行解碼,用ISO8859-1進行編碼。運行效果圖如下:
Android網絡編程之傳遞數據給服務器(二)——通過POST的方式將數據傳遞給服務器
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