數據提交（ｇｅｔ和ｐｏｓｔ）

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.itheim28.submitdata"
    android:versionCode="1"
    android:versionName="1.0" >


    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />
    <uses-permission android:name="android.permission.INTERNET"/>


    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.itheim28.submitdata.MainActivity2"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />


                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

public class NetUtils {


private static final String TAG = "NetUtils";

/**
* 使用post的方式登錄
* @param userName
* @param password
* @return
*/
public static String loginOfPost(String userName, String password) {
HttpURLConnection conn = null;
try {
URL url = new URL("http://10.0.2.2:8080/ServerItheima28/servlet/LoginServlet");

conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("POST");
conn.setConnectTimeout(10000); // 連接的超時時間
conn.setReadTimeout(5000); // 讀數據的超時時間
conn.setDoOutput(true); // 必須設置此方法, 允許輸出
// conn.setRequestProperty("Content-Length", 234); // 設置請求頭消息, 可以設置多個

// post請求的參數
String data = "username=" + userName + "&password=" + password;

// 獲得一個輸出流, 用於向服務器寫數據, 默認情況下, 系統不允許向服務器輸出內容
OutputStream out = conn.getOutputStream();
out.write(data.getBytes());
out.flush();
out.close();

int responseCode = conn.getResponseCode();
if(responseCode == 200) {
InputStream is = conn.getInputStream();
String state = getStringFromInputStream(is);
return state;
} else {
Log.i(TAG, "訪問失敗: " + responseCode);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if(conn != null) {
conn.disconnect();
}
}
return null;
}


/**
* 使用get的方式登錄
* @param userName
* @param password
* @return 登錄的狀態
*/
public static String loginOfGet(String userName, String password) {
HttpURLConnection conn = null;
try {
String data = "username=" + URLEncoder.encode(userName) + "&password=" + URLEncoder.encode(password);
URL url = new URL("http://10.0.2.2:8080/ServerItheima28/servlet/LoginServlet?" + data);
conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("GET"); // get或者post必須得全大寫
conn.setConnectTimeout(10000); // 連接的超時時間
conn.setReadTimeout(5000); // 讀數據的超時時間

int responseCode = conn.getResponseCode();
if(responseCode == 200) {
InputStream is = conn.getInputStream();
String state = getStringFromInputStream(is);
return state;
} else {
Log.i(TAG, "訪問失敗: " + responseCode);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if(conn != null) {
conn.disconnect(); // 關閉連接
}
}
return null;
}

/**
* 根據流返回一個字符串信息
* @param is
* @return
* @throws IOException 
*/
private static String getStringFromInputStream(InputStream is) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = -1;

while((len = is.read(buffer)) != -1) {
baos.write(buffer, 0, len);
}
is.close();

String html = baos.toString(); // 把流中的數據轉換成字符串, 採用的編碼是: utf-8

// String html = new String(baos.toByteArray(), "GBK");

baos.close();
return html;
}
}

public class MainActivity extends Activity {


private EditText etUserName;
private EditText etPassword;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

etUserName = (EditText) findViewById(R.id.et_username);
etPassword = (EditText) findViewById(R.id.et_password);
}


public void doGet(View v) {
final String userName = etUserName.getText().toString();
final String password = etPassword.getText().toString();

new Thread(
new Runnable() {

@Override
public void run() {
// 使用get方式抓去數據
final String state = NetUtils.loginOfGet(userName, password);

// 執行任務在主線程中
runOnUiThread(new Runnable() {
@Override
public void run() {
// 就是在主線程中操作
Toast.makeText(MainActivity.this, state, 0).show();
}
});
}
}).start();
}

public void doPost(View v) {
final String userName = etUserName.getText().toString();
final String password = etPassword.getText().toString();

new Thread(new Runnable() {
@Override
public void run() {
final String state = NetUtils.loginOfPost(userName, password);
// 執行任務在主線程中
runOnUiThread(new Runnable() {
@Override
public void run() {
// 就是在主線程中操作
Toast.makeText(MainActivity.this, state, 0).show();
}
});
}
}).start();
}
}