HTTP协议访问网络——HttpURLConnection
-
- HttpURLConnection的使用
- HttpURLConnection的实例
- 主函数
- 布局
- 总结
- HttpURLConnection的实例
- 单线程下载和多线程下载及网络连接
- MainActivity
- IndexActivity
- DownLoadActivity
- MultiThread
- activity_mainxml
- activity_indexxml
- activity_downloadxml
- AndroidManifestxml的配置
- HttpURLConnection的使用
HttpURLConnection的使用
1、首先要获取到HttpURLConnection的实例，一般只需要new出一个URL对象，并传入目标的网络地址，然后调用一下openConnection()方法即可。
URL url=new URL(“http://www.baidu.com“);
HttpURLConnection connection=(HttpURLConnection)url.openConnection();2、得到了HttpURLConnection的实例之后，我们可以设置一下HTTP请求所使用的方法。常用的方法主要有两个，GET和POST。GET表示希望从服务器那里获取数据，而POST则表示希望提交数据给服务器，写法如下：
connection.setRequestMethod(“GET”);
3、现在我们可以进行一些自由的定制了，比如设置连接超时。读取超时的毫秒数，以及服务器希望得到的一些消息头等。示例如下：
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);4、调用getInputStream()方法就可以获取到服务器返回的输入流，剩下的就是对输入流进行读取，如下所示：
InputStream is=connection.getInputStream();
5、最后调用disconnect()方法将这个HTTP连接关闭掉。如下所示：
connection.disconnect();
HttpURLConnection的实例
主函数
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
public static final int SHOW_RESPPONSE=0X12;
private Button mButtonSendRequest;
private TextView mTextViewResponse;
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
switch (msg.what){
case SHOW_RESPPONSE:
String content= (String) msg.obj;
mTextViewResponse.setText(content);
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mButtonSendRequest= (Button) findViewById(R.id.send_request);
mTextViewResponse= (TextView) findViewById(R.id.response);
mButtonSendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.send_request:
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection=null;
try {
URL url=new URL("http://www.baidu.com");
connection= (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream is=connection.getInputStream();
//下面对获取到的输入流进行读取
BufferedReader br=new BufferedReader(new InputStreamReader(is));
StringBuilder builder=new StringBuilder();//这里用StringBuilder和StringBuffer都可以
String line=br.readLine();
while (line!=null) {
builder.append(line);
line = br.readLine();
}
Message msg=handler.obtainMessage();
msg.what=SHOW_RESPPONSE;
msg.obj=builder.toString();
handler.sendMessage(msg);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
break;
}
}布局
<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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical" tools:context=".MainActivity">
<Button
android:id="@+id/send_request"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Send Request "/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/response"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</ScrollView>
</LinearLayout>总结
1、在按钮点击事件中先是开启了一个子线程，然后在子线程里使用了HttpURLConnection发出一条HTTP请求，请求的目的地址就是百度的首页，接着利用BufferedReader对服务器返回的流进行读取，并将结果存放到builder中。最后在放入Message对象中，至于这里为什么要使用Message对象——是因为子线程中无法对UI进行操作。我们希望可以将服务器返回的内容显示到界面上，所以创建了UI个Message对象并使用Handler将它发送出去，之后在handlerMessage（）方法中对这条Message进行处理，最终取出结果并设置到TextView上。
2、在布局中我使用了一个新控件——ScrollView，由于手机屏幕空间一般较小，有时候过多的内容一屏是显示不下的，借助ScrollView控件的话就可以允许我们以滚动的形式查看屏幕以外的那部分内容。另外，布局中还设置了一个Button和一个TextView，Button用于发送HTTP请求，TextView用于将服务器返回的数据显示出来。
单线程下载和多线程下载、及网络连接
MainActivity
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private Button mButtonContent;
private TextView mTextCiewContent;
private static final int URL_CONNECT=0X123;
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case URL_CONNECT:
String content= (String) msg.obj;
mTextCiewContent.setText(content);
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mButtonContent= (Button) findViewById(R.id.button_content);
mButtonContent.setOnClickListener(this);
mTextCiewContent= (TextView) findViewById(R.id.textview_content);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button_content:
new Thread(new Runnable() {
@Override
public void run() {
ConnectURL();
}
}).start();
break;
}
}
private void ConnectURL() {
try {
// URL url=new URL("http://192.168.0.102:8080/MyServerTest/MyTestServerlet");
URL url=new URL("http://www.360.com");
URLConnection connection=url.openConnection();
InputStream is=connection.getInputStream();
BufferedReader br=new BufferedReader(new InputStreamReader(is));
String line=br.readLine();
StringBuffer buffer=new StringBuffer();
while(line!=null){
Log.d("", line);
buffer.append(line);
line=br.readLine();
}
Message msg=handler.obtainMessage();
msg.what=URL_CONNECT;
msg.obj=buffer.toString().trim();
handler.sendMessage(msg);
br.close();
is.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
IndexActivity
public class IndexActivity extends AppCompatActivity implements View.OnClickListener{
private Button mButtonURLConnection;
private Button mButtonDownload;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_index);
mButtonURLConnection= (Button) findViewById(R.id.button_urlconnection);
mButtonDownload= (Button) findViewById(R.id.button_download);
mButtonURLConnection.setOnClickListener(this);
mButtonDownload.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button_download:
Intent intentDowanload=new Intent(getApplicationContext(),DownLoadActivity.class);
startActivity(intentDowanload);
break;
case R.id.button_urlconnection:
Intent intentUrl=new Intent(getApplicationContext(),MainActivity.class);
startActivity(intentUrl);
break;
}
}
}DownLoadActivity
public class DownLoadActivity extends AppCompatActivity implements View.OnClickListener {
private Button mButtonSingle;
private Button mButtonMore;
private ProgressBar mProgressBar;
private int length;
private static final int SEND_SUM = 0X123;
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what){
case SEND_SUM:
mProgressBar.setProgress(msg.arg1*100/length);
break;
}
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_download);
mButtonSingle = (Button) findViewById(R.id.button_single);
mButtonMore = (Button) findViewById(R.id.button_more);
mButtonSingle.setOnClickListener(this);
mButtonMore.setOnClickListener(this);
mProgressBar = (ProgressBar) findViewById(R.id.progressbar);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button_single:
SingleDownloadTask singleDownloadTask = new SingleDownloadTask();
singleDownloadTask.execute();
break;
case R.id.button_more:
new Thread(new Runnable() {
@Override
public void run() {
try {
String urlPath = "http://192.168.0.43:8080/www/music/sj.mp3";
URL url = new URL(urlPath);
URLConnection connection = url.openConnection();
length = connection.getContentLength();
File file = new File(Environment.getExternalStorageDirectory(), "aa.mp3");
if (!file.exists()) {
file.createNewFile();
}
MultiThread[] threads = new MultiThread[5];
for (int i = 0; i < 5; i++) {
MultiThread thread = null;
if (i == 4) {
thread = new MultiThread(length / 5 * 4, length, urlPath, file.getAbsolutePath());
} else {
thread = new MultiThread(length / 5 * i, length / 5 * ((i + 1)-1), urlPath, file.getAbsolutePath());
}
thread.start();
threads[i] = thread;
}
boolean isFinish = true;
while (isFinish) {
int sum = 0;
for (MultiThread thread : threads) {
sum += thread.getSum();
}
Message msg = handler.obtainMessage();
msg.what = SEND_SUM;
msg.arg1 = sum;
handler.sendMessage(msg);
if (sum + 10 >= length) {
isFinish = false;
}
Thread.sleep(1000);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}).start();
break;
}
}
class SingleDownloadTask extends AsyncTask<String, Integer, String> {
@Override
protected void onProgressUpdate(Integer... values) {//...三个点表示参数个数不定
super.onProgressUpdate(values);
mProgressBar.setProgress((int) (values[0] * 100.0 / values[1]));//sum表示数组[0],length表示数组[1]
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
}
@Override
protected String doInBackground(String... params) {
try {
URL url = new URL("http://192.168.0.43:8080/www/music/sj.mp3");
URLConnection connection = url.openConnection();//打开连接
length = connection.getContentLength();//得到内容总长度
InputStream is = connection.getInputStream();//得到输入流
//将Environment.getExternalStorageDirectory()路径下的takingmeaway.mp3文件实例化
File file = new File(Environment.getExternalStorageDirectory(), "takingmeaway.mp3");
if (!file.exists()) {
file.createNewFile();
}
FileOutputStream outputStream = new FileOutputStream(file);//输出流将文件输入到file
byte[] array = new byte[1024];
int sum = 0;
int index = is.read(array);//从输入流中读出文件放在数组array中
while (index != -1) {
outputStream.write(array, 0, index);//将数组中的文件写入到file中，从数组的第一个即下标号0处开始读入
sum += index;
publishProgress(sum, length);//将参数传入onProgressUpdate中，设置进度条
index = is.read(array);
}
outputStream.flush();
outputStream.close();
is.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
}
MultiThread
public class MultiThread extends Thread{
private int sum=0;
private long start;
private long end;
private String urlPath;
private String filePath;
public MultiThread(long start,long end, String url, String filePath) {
this.start=start;
this.end=end;
this.urlPath=url;
this.filePath=filePath;
}
public int getSum(){
return sum;
}
@Override
public void run() {
try {
URL url=new URL(urlPath);
URLConnection connection=url.openConnection();
connection.setAllowUserInteraction(true);//允许用户进行交互
//setRequestProperty是告诉服务器 我的客户端的配置、需求.这里设置了从开始到结束的范围
connection.setRequestProperty("Range", "bytes=" + start + "-" + end);
InputStream is=connection.getInputStream();
File file=new File(filePath);
if (!file.exists()){
file.createNewFile();
}
//RandomAccessFile是用来访问那些保存数据记录的文件的
RandomAccessFile randomAccessFile=new RandomAccessFile(file,"rw");
randomAccessFile.seek(start);//在文件里移动用seek()方法;
byte []array=new byte[1024];
int index=is.read(array);
sum=0;
while (index!=-1){
randomAccessFile.write(array,0,index);
sum+=index;
index=is.read(array);
}
randomAccessFile.close();
is.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
activity_main.xml
<ScrollView 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=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<Button
android:id="@+id/button_content"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="连接网络"
/>
<TextView
android:id="@+id/textview_content"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="内容"/>
</LinearLayout>
</ScrollView>
activity_index.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/button_urlconnection"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="HTTPurlconnectionn"/>
<Button
android:id="@+id/button_download"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="下载文件"/>
</LinearLayout>
</ScrollView>
activity_download.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ProgressBar
android:id="@+id/progressbar"
android:layout_width="match_parent"
android:layout_height="25dp"
android:layout_marginTop="20dp"
style="@style/Base.Widget.AppCompat.ProgressBar.Horizontal"/>
<Button
android:id="@+id/button_single"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="单线程下载"/>
<Button
android:id="@+id/button_more"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="多线程下载"/>
</LinearLayout>
</ScrollView>
AndroidManifest.xml的配置
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.administrator.myurlconnection" >
<!--连接网络的权限-->
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<!--可写入存储卡的权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
<!--可读存储卡的权限 -->
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="myurlconnection"
android:theme="@style/AppTheme" >
<activity android:name=".IndexActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity"></activity>
<activity android:name=".DownLoadActivity"></activity>
</application>
</manifest>
总结：代码中用到了单线程和多线程，以及用来传递消息的Handler类、设置进度条的方法、RandomAccessFile类（是用来访问那些保存数据记录的文件的）和它的相关方法，比如： RandomAccessFile randomAccessFile=new RandomAccessFile(file,”rw”);
randomAccessFile.seek(start); 当然上面程序的很多方法我都已经给出了相应的解释，只要耐心看程序就会看懂滴*-*