Android平台有三种网络接口可以使用,他们分别是:java.net.*(标准Java接口)、Org.apache接口和Android.net.*(Android网络接口)。下面分别介绍这些接口的功能和作用。
?1.标准Java接口
java.net.*提供与联网有关的类,包括流、数据包套接字(socket)、Internet协议、常见Http处理等。比如:创建URL,以及URLConnection/HttpURLConnection对象、设置链接参数、链接到服务器、向服务器写数据、从服务器读取数据等通信。这些在Java网络编程中均有涉及,我们看一个简单的socket编程,实现服务器回发客户端信息。
下面用个例子来说明:
A、客户端:
新建Android项目工程:SocketForAndroid(这个随意起名字了吧,我是以这个建立的!)
下面是main_activity.xml的代码:
<?xml?version="1.0"?encoding="utf-8"?> <LinearLayout?xmlns:android="http://schemas.android.com/apk/res/android" ????android:layout_width="fill_parent" ????android:layout_height="fill_parent" ????android:orientation="vertical"> ????<TextView ????????android:layout_width="fill_parent" ????????android:layout_height="wrap_content" ????????android:text="@string/hello"?/> ????<EditText ????????android:id="@+id/message" ????????android:layout_width="match_parent" ????????android:layout_height="wrap_content" ????????android:hint="@string/hint"?/> ????<Button ????????android:id="@+id/send" ????????android:layout_width="fill_parent" ????????android:layout_height="wrap_content" ????????android:text="@string/send"?/> </LinearLayout>
MainActivity.java的代码入下:
package?com.yaowen.socketforandroid; import?android.os.Bundle; import?android.support.v7.app.AppCompatActivity; import?android.view.View; import?android.widget.Button; import?android.widget.EditText; import?java.io.BufferedReader; import?java.io.BufferedWriter; import?java.io.IOException; import?java.io.InputStreamReader; import?java.io.OutputStreamWriter; import?java.io.PrintWriter; import?java.net.Socket; public?class?MainActivity?extends?AppCompatActivity?{ ????private?EditText?message; ????private?Button?send; ????@Override ????protected?void?onCreate(Bundle?savedInstanceState)?{ ????????super.onCreate(savedInstanceState); ????????setContentView(R.layout.activity_main); ????????//初始化两个UI控件 ????????message?=?(EditText)?findViewById(R.id.message); ????????send?=?(Button)?findViewById(R.id.send); ????????//设置发送按钮的点击事件响应 ????????send.setOnClickListener(new?View.OnClickListener()?{ ????????????@Override ????????????public?void?onClick(View?v)?{ ????????????????Socket?socket?=?null; ????????????????//获取message输入框里的输入的内容 ????????????????String?msg?=?message.getText().toString()?+?"/r/n"; ????????????????try?{ ????????????????????//这里必须是192.168.3.200,不可以是localhost或者127.0.0.1 ????????????????????socket?=?new?Socket("192.168.3.200",?18888); ????????????????????PrintWriter?out?=?new?PrintWriter( ????????????????????????????new?BufferedWriter( ????????????????????????????????????new?OutputStreamWriter( ????????????????????????????????????????????socket.getOutputStream() ????????????????????????????????????) ????????????????????????????),?true); ????????????????????//发送消息 ????????????????????out.println(msg); ????????????????????//接收数据 ????????????????????BufferedReader?in?=?new?BufferedReader( ????????????????????????new?InputStreamReader( ????????????????????????????socket.getInputStream() ????????????????????????) ????????????????????); ????????????????????//读取接收的数据 ????????????????????String?msg_in?=?in.readLine(); ????????????????????if?(null?!=?msg_in)?{ ????????????????????????message.setText(msg_in); ????????????????????????System.out.println(msg_in); ????????????????????}?else?{ ????????????????????????message.setText("接收的数据有误!"); ????????????????????} ????????????????????//关闭各种流 ????????????????????out.close(); ????????????????????in.close(); ????????????????}?catch?(IOException?e)?{ ????????????????????e.printStackTrace(); ????????????????}?finally?{ ????????????????????try?{ ????????????????????????if?(null?!=?socket)?{ ????????????????????????????//socket不为空时,最后记得要把socket关闭 ????????????????????????????socket.close(); ????????????????????????} ????????????????????}?catch?(IOException?e)?{ ????????????????????????e.printStackTrace(); ????????????????????} ????????????????} ????????????} ????????}); ????} }
最后别忘记添加访问网络权限:
<uses-permission?android:name="android.permission.INTERNET"?/>
B、服务端:
package?service; import?java.io.BufferedReader; import?java.io.BufferedWriter; import?java.io.IOException; import?java.io.InputStreamReader; import?java.io.OutputStreamWriter; import?java.io.PrintWriter; import?java.net.ServerSocket; import?java.net.Socket; public?class?ServerAndroid?implements?Runnable?{ ?@Override ?public?void?run()?{ ??Socket?socket?=?null; ??try?{ ???ServerSocket?server?=?new?ServerSocket(18888); ???//?循环监听客户端链接请求 ???while?(true)?{ ????System.out.println("start..."); ????//?接收请求 ????socket?=?server.accept(); ????System.out.println("accept..."); ????//?接收客户端消息 ????BufferedReader?in?=?new?BufferedReader(new?InputStreamReader(socket.getInputStream())); ????String?message?=?in.readLine(); ????System.out.println(message); ????//?发送消息,向客户端 ????PrintWriter?out?=?new?PrintWriter(new?BufferedWriter(new?OutputStreamWriter(socket.getOutputStream())), ??????true); ????out.println("Server:"?+?message); ????//?关闭流 ????in.close(); ????out.close(); ???} ??}?catch?(IOException?e)?{ ???e.printStackTrace(); ??}?finally?{ ???if?(null?!=?socket)?{ ????try?{ ?????socket.close(); ????}?catch?(IOException?e)?{ ?????e.printStackTrace(); ????} ???} ??} ?} ?//?启动服务器 ?public?static?void?main(String[]?args)?{ ??Thread?server?=?new?Thread(new?ServerAndroid()); ??server.start(); ?} }
C、启动服务器,控制台会打印出“start…”字符串!
D、运行Android项目文件,如下图:
在输入框里输入如下字符串,点发送按钮:
服务器收到客户端发来的消息并打印到控制台:
2、Apache接口
对于大部分应用程序而言JDK本身提供的网络功能已远远不够,这时就需要Android提供的Apache HttpClient了。它是一个开源项目,功能更加完善,为客户端的Http编程提供高效、最新、功能丰富的工具包支持。
下面我们以一个简单例子来看看如何使用HttpClient在Android客户端访问Web。
首先,要在你的机器上搭建一个web应用test,有两个很简单的PHP文件:hello_get.php和hello_post.php!
内容如下:
hello_get.php的代码如下:
<html> ?<body> ??Welcome?<?php?echo?$_GET["name"];??><br> ??You?connected?this?page?on?:?<?php?echo?$_GET["get"];??> ?</body> </html>
hello_post.php的代码如下:
<html> <body> Welcome?<?php?echo?$_POST["name"];??><br> You?connected?this?page?on?:?<?php?echo?$_POST["post"];??> </body> </html>
在原来的Android项目里新建一个Apache活动类:Apache.java,代码如下:
package?com.yaowen.socketforandroid; import?android.os.Bundle; import?android.support.v7.app.AppCompatActivity; import?android.view.View; import?android.widget.Button; import?android.widget.TextView; import?org.apache.http.HttpEntity; import?org.apache.http.HttpResponse; import?org.apache.http.NameValuePair; import?org.apache.http.client.ClientProtocolException; import?org.apache.http.client.HttpClient; 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?java.io.BufferedReader; import?java.io.IOException; import?java.io.InputStreamReader; import?java.io.UnsupportedEncodingException; import?java.util.ArrayList; import?java.util.List; /** ?*?Created?by?YAOWEN?on?2015/11/10. ?*/ public?class?ApacheActivity?extends?AppCompatActivity?implements?View.OnClickListener?{ ????private?TextView?textView; ????private?Button?get1,?post1; ????@Override ????protected?void?onCreate(Bundle?savedInstanceState)?{ ????????super.onCreate(savedInstanceState); ????????setContentView(R.layout.apache); ????????textView?=?(TextView)?findViewById(R.id.textView); ????????get1?=?(Button)?findViewById(R.id.get); ????????post1?=?(Button)?findViewById(R.id.post); ????????get1.setOnClickListener(this); ????????post1.setOnClickListener(this); ????} ????@Override ????public?void?onClick(View?v)?{ ????????if?(v.getId()?==?R.id.get)?{ ????????????//注意:此处ip不能用127.0.0.1或localhost,Android模拟器已将它自己作为了localhost ????????????String?url?=?"http://192.168.3.200/test/hello_get.php?name=yaowen&get=GET"; ????????????textView.setText(get(url)); ????????} ????????if?(v.getId()?==?R.id.post)?{ ????????????String?url="http://192.168.3.200/test/hello_post.php"; ????????????textView.setText(post(url)); ????????} ????} ????/** ?????*?以post方式发送请求,访问web ?????* ?????*?@param?url?web地址 ?????*?@return?响应数据 ?????*/ ????private?String?post(String?url)?{ ????????BufferedReader?reader?=?null; ????????StringBuffer?sb?=?null; ????????String?result?=?""; ????????HttpClient?client?=?new?DefaultHttpClient(); ????????HttpPost?requset?=?new?HttpPost(url); ????????//保存要传递的参数 ????????List<NameValuePair>?params?=?new?ArrayList<NameValuePair>(); ????????//添加参数 ????????params.add(new?BasicNameValuePair("name",?"yaowen")); ????????params.add(new?BasicNameValuePair("post","POST")); ????????try?{ ????????????HttpEntity?entity?=?new?UrlEncodedFormEntity(params,?"utf-8"); ????????????requset.setEntity(entity); ????????????HttpResponse?response?=?client.execute(requset); ????????????if?(response.getStatusLine().getStatusCode()?==?200)?{ ????????????????System.out.println("post?success"); ????????????????reader?=?new?BufferedReader(new?InputStreamReader(response.getEntity().getContent())); ????????????????sb?=?new?StringBuffer(); ????????????????String?line?=?""; ????????????????String?NL?=?System.getProperty("line.separator"); ????????????????while?((line?=?reader.readLine())?!=?null)?{ ????????????????????sb.append(line); ????????????????} ????????????} ????????}?catch?(UnsupportedEncodingException?e)?{ ????????????e.printStackTrace(); ????????}?catch?(ClientProtocolException?e)?{ ????????????e.printStackTrace(); ????????}?catch?(IOException?e)?{ ????????????e.printStackTrace(); ????????}?finally?{ ????????????if?(null?!=?reader)?{ ????????????????try?{ ????????????????????reader.close(); ????????????????}?catch?(IOException?e)?{ ????????????????????e.printStackTrace(); ????????????????} ????????????} ????????????if?(null?!=?sb)?{ ????????????????result?=?sb.toString(); ????????????} ????????} ????????return?result; ????} ????/** ?????*?以get方式发送请求,访问web ?????* ?????*?@param?url?web地址 ?????*?@return?响应数据 ?????*/ ????private?static?String?get(String?url)?{ ????????BufferedReader?bufferedReader?=?null; ????????StringBuffer?sb?=?null; ????????String?result?=?""; ????????HttpClient?client?=?new?DefaultHttpClient(); ????????HttpGet?request?=?new?HttpGet(url); ????????//发送请求,得到响应 ????????try?{ ????????????HttpResponse?response?=?client.execute(request); ????????????//请求成功 ????????????if?(response.getStatusLine().getStatusCode()?==?200)?{ ????????????????bufferedReader?=?new?BufferedReader( ????????????????????????new?InputStreamReader( ????????????????????????????????response.getEntity() ????????????????????????????????????????.getContent() ????????????????????????) ????????????????); ????????????????sb?=?new?StringBuffer(); ????????????????String?line?=?""; ????????????????String?NL?=?System.getProperty("line.separator"); ????????????????while?((line?=?bufferedReader.readLine())?!=?null)?{ ????????????????????sb.append(line); ????????????????} ????????????} ????????}?catch?(IOException?e)?{ ????????????e.printStackTrace(); ????????}?finally?{ ????????????if?(null?!=?bufferedReader)?{ ????????????????try?{ ????????????????????bufferedReader.close(); ????????????????????//bufferedReader=null; ????????????????}?catch?(IOException?e)?{ ????????????????????e.printStackTrace(); ????????????????} ????????????} ????????????if?(null?!=?sb)?{ ????????????????result?=?sb.toString(); ????????????} ????????} ????????return?result; ????} }
新建一个apache.XML文件,如下:
<?xml?version="1.0"?encoding="utf-8"?> <LinearLayout?xmlns:android="http://schemas.android.com/apk/res/android" ????android:layout_width="fill_parent" ????android:layout_height="fill_parent" ????android:orientation="vertical"> ????<TextView ????????android:id="@+id/textView" ????????android:layout_width="fill_parent" ????????android:layout_height="wrap_content" ????????android:gravity="center" ????????android:text="通过按钮选择不同方式访问网页"?/> ????<Button ????????android:id="@+id/get" ????????android:layout_width="match_parent" ????????android:layout_height="wrap_content" ????????android:text="get"?/> ????<Button ????????android:id="@+id/post" ????????android:layout_width="match_parent" ????????android:layout_height="wrap_content" ????????android:text="post"?/> </LinearLayout>
结果运行如下:
3.android.net编程
常常使用此包下的类进行Android特有的网络编程,如:访问WiFi,访问Android联网信息,邮件等功能。
这里就不详细做例子了,因为这个接触比较多~~~。