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URL的openConnection方法将傳回一個URLConnection,該對象表示應用程式和URL之間的通信連接配接。程式可以通過它的執行個體向該URL發送請求,讀取URL引用的資源。
下面通過一個簡單示例來示範:
Activity:
package com.home.urlconnection;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
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.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity implements OnClickListener {
private Button urlConnectionBtn;
private Button httpUrlConnectionBtn;
private Button httpClientBtn;
private TextView showTextView;
private WebView webView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}
private void init() {
urlConnectionBtn = (Button) findViewById(R.id.test_url_main_btn_urlconnection);
httpUrlConnectionBtn = (Button) findViewById(R.id.test_url_main_btn_httpurlconnection);
httpClientBtn = (Button) findViewById(R.id.test_url_main_btn_httpclient);
showTextView = (TextView) findViewById(R.id.test_url_main_tv_show);
webView = (WebView) findViewById(R.id.test_url_main_wv);
urlConnectionBtn.setOnClickListener(this);
httpUrlConnectionBtn.setOnClickListener(this);
httpClientBtn.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v == urlConnectionBtn) {
try {
// 直接使用URLConnection對象進行連接配接
URL url = new URL("http://192.168.1.100:8080/myweb/hello.jsp");
// 得到URLConnection對象
URLConnection connection = url.openConnection();
InputStream is = connection.getInputStream();
byte[] bs = new byte[1024];
int len = 0;
StringBuffer sb = new StringBuffer();
while ((len = is.read(bs)) != -1) {
String str = new String(bs, 0, len);
sb.append(str);
}
showTextView.setText(sb.toString());
} catch (Exception e) {
e.printStackTrace();
}
}
if (v == httpUrlConnectionBtn) {
// 直接使用HttpURLConnection對象進行連接配接
try {
URL url = new URL(
"http://192.168.1.100:8080/myweb/hello.jsp?username=abc");
// 得到HttpURLConnection對象
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
// 設定為GET方式
connection.setRequestMethod("GET");
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
// 得到響應消息
String message = connection.getResponseMessage();
showTextView.setText(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}
if (v == httpClientBtn) {
try {
// 使用ApacheHttp用戶端進行連接配接(重要方法)
HttpClient client = new DefaultHttpClient();
// 如果是Get送出則建立HttpGet對象,否則建立HttpPost對象
// POST送出的方式
HttpPost httpPost = new HttpPost(
"http://192.168.1.100:8080/myweb/hello.jsp");
// 如果是Post送出可以将參數封裝到集合中傳遞
List dataList = new ArrayList();
dataList.add(new BasicNameValuePair("username", "abc"));
dataList.add(new BasicNameValuePair("pwd", "123"));
// UrlEncodedFormEntity用于将集合轉換為Entity對象
httpPost.setEntity(new UrlEncodedFormEntity(dataList));
// GET送出的方式
// HttpGet httpGet = new
// HttpGet("http://192.168.1.100:8080/myweb/hello.jsp?username=abc&pwd=321");
// 擷取相應消息
HttpResponse httpResponse = client.execute(httpPost);
// 擷取消息内容
HttpEntity entity = httpResponse.getEntity();
// 把消息對象直接轉換為字元串
String content = EntityUtils.toString(entity);
// 顯示在TextView中
// showTextView.setText(content);
// 通過webview來解析網頁
webView.loadDataWithBaseURL(null, content, "text/html",
"utf-8", null);
// 直接根據url來進行解析
// webView.loadUrl(url);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
上面使用到的url是部署在筆者本機的web應用,這裡不再給出,大家可以換成自己的web應用即可。
布局XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="@+id/test_url_main_btn_urlconnection"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="使用URLConnection連接配接" />
<Button
android:id="@+id/test_url_main_btn_httpurlconnection"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="使用HttpURLConnection連接配接" />
<Button
android:id="@+id/test_url_main_btn_httpclient"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="使用Apache用戶端連接配接" />
<TextView
android:id="@+id/test_url_main_tv_show"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<WebView
android:id="@+id/test_url_main_wv"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
權限:
<uses-permission android:name="android.permission.INTERNET" />