目录
1、使用Android的HttpURLConnection步骤
4)调用getInputStream()方法获取返回的输入流
一、使用HttpURLConnection
1、使用Android的HttpURLConnection步骤
1）获取HttpURLConnection实例
URL url = new URL("http://www.baidu.com");
HttpURLConnection connection = (HtppURLConnection) url.openConnection();2)设置HTTP请求使用的方法
connection.setRequestMethod("GET");3)定制HTTP请求，如连接超时、读取超时的毫秒数
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);4)调用getInputStream()方法获取返回的输入流
InputStream in = connection.getInputStream();5)关闭HTTP连接
connection.disconnect();2、实例
新建NetWorkTest项目，
修改activity_main.xml代码，如下：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<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_text"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</ScrollView>
</LinearLayout>修改MainActivity的代码，如下：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sendRequest = (Button) findViewById(R.id.send_request);
responseText = (TextView) findViewById(R.id.response_text);
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
sendRequestWithHttpURLConnection();
}
}
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("https://www.baidu.com");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
// 下面对获取到的输入流进行读取
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while((line = reader.readLine()) != null){
response.append(line);
}
showResponse(response.toString());
} catch (Exception e) {
e.printStackTrace();
}finally {
if(reader != null){
try {
reader.close();
}catch (IOException e){
e.printStackTrace();
}
}
if(connection != null){
connection.disconnect();
}
}
}
}).start();
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
// 在这里进行UI操作，将结果显示到界面上
responseText.setText(response);
}
});
}
}最后声明网络权限，修改AndroidManifest.xml代码，如下：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<uses-permission android:name="android.permission.INTERNET" />
................效果如下：
这是百度浏览器的HTML代码。
如何将数据提交给服务器？
如我们想向服务器提交用户名和密码，代码如下：
connection.setRequestMethod("POST");
DataOutputStream out = new DataOutputStream(connection.getOutputStream);
out.writeBytes("username=admin&password=123456");二、使用OkHttp
以上方法是原生方法，接下来使用的OkHttp是比较出色的网络通信库。
在使用之前，需要现在项目中添加OkHttp库的依赖，修改app/build.gradle文件，在dependencies闭包中添加以下内容。
dependencies {
...........
implementation 'com.squareup.okhttp3:okhttp:3.4.1'1、使用OkHttpClient的步骤
1）创建OkHttpClient实例
OkHttpClient client = new OkHttpClient();2)创建Request对象
Request request = new Request.Builder().build();
3)设置目标网络的URL地址
Request request = new Request.Builder()
.url("http://www.baidu.com")
.build();4)发送请求获取服务器返回的数据
Response response = client.newCall(request).execute();5)获得返回的具体内容
String responseData = response.body().string();如果发起一条POST请求，需要先构建一个RequestBody对象来存放待提交的参数，如下：
RequestBody requestBody = new FormBody.Builder()
.add("username","admin")
.add("password","123456")
.build();然后再Request.Builder中调用post()方法，将RequestBody对象传入：
Request request = new Request.Builder()
.url("http://www.baidu.com")
.post(requestBody)
.build();下面的操作和GET请求一样，调用execute()方法来发送请求并获取服务器返回的数据。
2、实例
在上面的项目中修改。
布局部分不动，修改MainActivity代码，如下：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sendRequest = (Button) findViewById(R.id.send_request);
responseText = (TextView) findViewById(R.id.response_text);
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
// sendRequestWithHttpURLConnection();
sendRequestWithOkHttp();
}
}
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://www.bjtu.edu.cn")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
showResponse(responseData);
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
private void sendRequestWithHttpURLConnection() {
// 开启线程来发起网络请求
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("https://www.bjtu.edu.cn");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
// 下面对获取到的输入流进行读取
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (Exception e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
// 在这里进行UI操作，将结果显示到界面上
responseText.setText(response);
}
});
}
}
