android 使用httpclient访问网络

在主活动类中，调用一个线程访问网络（android4.0以上耗时的操作不能放在主线程中）：

//声明两个Button对象，与一个TextView对象
private TextView mTextView1;
    private Button mButton1, mButton2;

    private static final int MSG_SUCCESS = 0;
    private static final int MSG_FAILURE = 1;
    private Thread mThread;//在android4.0及以上，非UI操作放在主线程会报错，因此在这里获取网络数据需要开启一个线程

    private Handler myHandler = new Handler(){
        public void handleMessage(Message msg){//此方法在Ui线程执行
            switch(msg.what){
            case MSG_SUCCESS:
                mTextView1.setText("成功！返回数据：");
                mTextView1.append(msg.toString());
                break;
            case MSG_FAILURE:
                Toast.makeText(MainActivity.this, "网络异常", 1).show();
                break;
            }

        }
    };

    Runnable runnable = new Runnable(){
        @Override
        public void run() {//在新的线程中执行
            //声明网址字符串
            String uriAPI = "http://192.168.1.102:8080/AndroidDemo/demo.html";
            // 创建Http post连接
            HttpPost httpRequest = new HttpPost(uriAPI);
            // post 运行传送变量必须用NameValuePair[]数组存车场
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("str", "I am a Post String"));
            try {
                // 发送Http request
                httpRequest.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                // 取得Http response
                HttpResponse httpResponse = new DefaultHttpClient().execute(httpRequest);
                // 若状态码为200
                if (httpResponse.getStatusLine().getStatusCode() == 200) {
                    // 取出应答字符串
                    String strResult = EntityUtils.toString(httpResponse.getEntity());
                    Log.e("返回信息", strResult);
                  //  mTextView1.setText(strResult);
                    Message msg = Message.obtain();
                    msg.obj = strResult;
                    msg.arg1 = MSG_SUCCESS;
                    myHandler.sendMessage(msg);
                } else {
                    Log.e("返回信息", String.valueOf(httpResponse.getStatusLine().getStatusCode()));
                 //   mTextView1.setText("Error Response: " + httpResponse.getStatusLine().toString());
                }
            } catch (ClientProtocolException e) {
             //   mTextView1.setText(e.getMessage().toString());
                e.printStackTrace();
            } catch (IOException e) {
               // mTextView1.setText(e.getMessage().toString());
                e.printStackTrace();
            } catch (Exception e) {
               // mTextView1.setText("异常");
                e.printStackTrace();
            }
        }

    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.main);

         // 通过findviewbyid构造器创建TextView与button对象
        mButton1 = (Button) this.findViewById(R.id.get);
        mButton2 = (Button) this.findViewById(R.id.post);
        mTextView1 = (TextView) this.findViewById(R.id.text);
        //设置Onclicklistener来监听onclick事件
        mButton1.setOnClickListener(this);
        mButton2.setOnClickListener(this);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    //自定义字符串替换函数
    public String eregi_replace(String strFrom, String strTo, String strTarget) {
        String strPattern = "(?i)" + strFrom;
        Pattern p = Pattern.compile(strPattern);
        Matcher m = p.matcher(strTarget);
        if (m.find()) {
            return strTarget.replaceAll(strFrom, strTo);
        } else {
            return strTarget;
        }
    }
    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.get:
                /*
                // 声明网址字符串
                String uriAPI1 = "http://39.191.72.9:8080/AndroidDemo/demo.html";
                //创建Http Get连接
                HttpGet httpRequest1 = new HttpGet(uriAPI1);
                try {
                    //发送Http Request
                    HttpResponse httpResponse1 = new DefaultHttpClient().execute(httpRequest1);
                    //若状态码为200
                    if (httpResponse1.getStatusLine().getStatusCode() == 200) {
                        //取出应答字符串
                        String strResult1 = EntityUtils.toString(httpResponse1.getEntity());
                        //删除多余字符
                        strResult1 = eregi_replace("(\r\n|\r|\n|\n\r)", "", strResult1);
                        mTextView1.setText("成功！返回数据：");
                        mTextView1.append(strResult1);
                    }
                } catch (ClientProtocolException e) {
                    mTextView1.setText("异常");
                    e.printStackTrace();
                } catch (IOException e) {
                    mTextView1.setText("异常");
                    e.printStackTrace();
                } catch (Exception e) {
                    mTextView1.setText("异常");
                    e.printStackTrace();
                }
                */
                break;
            case R.id.post:
               // if(mThread == null){
                    mThread = new Thread(runnable);
                    mThread.start();
                //}
                //else{
                    //Toast.makeText(MainActivity.this, "系统异常", 1).show();
                //}
                break;
        }

    }

xml文件中布局：

<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:orientation="vertical"
    tools:context="com.example.httpdemo.app.MainActivity">
    <Button
        android:id="@+id/get"
        android:text="GET获取数据"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/post"
        android:text="POST获取数据"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

访问网络需要网络权限：

<uses-permission android:name="android.permission.INTERNET"/>