网路编程（网站源码查看器）

public class MainActivity extends Activity { protected static final int REQUESTSUCCESS = 0; //变大写ctrl+shift+X 变小写写ctrl+shift+Y  protected static final int REQUESTFAILED= 1; protected static final int REQUESTEXCEPTION = 2; private EditText et_path; private TextView tv_result; //在主线程中定义一个Handler private Handler handler = new Handler(){ //此方法在主线程中执行 public void handleMessage(android.os.Message msg) { //所以可在主线程更新ui switch (msg.what) { case REQUESTSUCCESS: String content = (String) msg.obj; tv_result.setText(content); break; case REQUESTFAILED: Toast.makeText(getApplicationContext(), "请求资源不存在", Toast.LENGTH_LONG).show(); break; case REQUESTEXCEPTION: Toast.makeText(getApplicationContext(), "服务器忙，请稍后再访问...", Toast.LENGTH_LONG).show(); break; default: break; } }; }; @SuppressLint("NewApi") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); et_path = (EditText) findViewById(R.id.et_path); tv_result = (TextView) findViewById(R.id.tv_result); // StrictMode.ThreadPolicy policy=new StrictMode.ThreadPolicy.Builder().permitAll().build(); // StrictMode.setThreadPolicy(policy); System.out.println("当前线程的名称："+Thread.currentThread().getName()); } // 点击按钮查看，获取指定路径的源码 public void click(View v) { // 2.0创建一个子线程 new Thread() { public void run() { try { // 2.1获取源码路径 String path = et_path.getText().toString().trim(); // 2.2创建url对象，指定我们要访问的网址(路径) URL url = new URL(path); // 2.3拿到HttpURLConnection对象，用于发送或接收数据 HttpURLConnection urlConnection = (HttpURLConnection) url .openConnection(); // 2.4设置发送get请求 urlConnection.setRequestMethod("GET");// get要求大写，默认为get请求 // 2.5设置请求的超时时间 urlConnection.setConnectTimeout(5000); // 2.6获取服务器返回的状态码 200请求成功 int code = urlConnection.getResponseCode(); if (code == 200) { // 2.7获取服务器返回的数据,以流的形式返回 InputStream inputStream = urlConnection .getInputStream(); String content = StreamTools.readStream(inputStream); // 2.8.0创建Message对象 Message msg = new Message(); msg.what = REQUESTSUCCESS; msg.obj = content; // 2.8.1拿着我们创建的Handler助手，告诉系统，我们需要更新ui handler.sendMessage(msg); // 发了一条消息，把消息放到msg里，handlerMessage方法执行 // 2.8将流的数据展示到TextView // tv_result.setText(content); } else { // 请求资源不存在 Toast是一个view 也不能在子线程更新ui Message msg = new Message(); msg.what = REQUESTFAILED; // 代表哪条消息  handler.sendMessage(msg); } } catch (Exception e) { Message msg = new Message(); msg.what = REQUESTEXCEPTION; // 代表哪条消息  handler.sendMessage(msg); e.printStackTrace(); } } }.start(); } } public class StreamTools { //把一个InputStream 转换成String public static String readStream(InputStream in) throws Exception{ //定义一个内存输出流 ByteArrayOutputStream baos = new ByteArrayOutputStream(); int len = -1; byte[] buffer = new byte[1024]; //1kb while((len = in.read(buffer))!= -1){ baos.write(buffer, 0, len); } in.close(); String content = new String(baos.toByteArray()); return content; } }

public class MainActivity extends Activity { private EditText et_path; private ImageView iv; @SuppressLint("NewApi") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); et_path = (EditText) findViewById(R.id.et_path); iv = (ImageView) findViewById(R.id.iv); } private Handler handler = new Handler(){ public void handleMessage(android.os.Message msg) { Bitmap bitmap = (Bitmap) msg.obj; iv.setImageBitmap(bitmap); }; }; // 点击按钮查看，获取指定路径的源码 public void click(View v) { new Thread(){ public void run(){ try { String path = et_path.getText().toString().trim(); //Base64.encodeToString(path.getBytes(), Base64.DEFAULT) 图片的文件名加密 File file = new File(getCacheDir(),Base64.encodeToString(path.getBytes(), Base64.DEFAULT)); //File file = new File(getCacheDir(),"test.png"); if(file.exists() && file.length()>0){ //使用缓存缓存的图片 System.out.println("使用缓存图片"); Bitmap cacheBitmap = BitmapFactory.decodeFile(file.getAbsolutePath()); Message msg = Message.obtain(); //使用Message的静态方法可以减少对象的创建 msg.obj = cacheBitmap; handler.sendMessage(msg); }else{ //第一次访问，联网获取数据 System.out.println("第一次联网获取数据"); //2.1获取访问图片的路径 //String path = et_path.getText().toString().trim(); //创建url对象 URL url = new URL(path); HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(); //2.4设置请求的方式 urlConnection.setRequestMethod("GET"); //2.5设置超时时间 urlConnection.setConnectTimeout(50000); //2.6获取服务器返回的状态码 int code = urlConnection.getResponseCode(); if(code == 200){ //2.7获取图片的数据,不管什么数据（txt,图片文本）都是以流的形式返回 InputStream inputStream = urlConnection.getInputStream(); //2.7.1缓存图片 谷歌给我们提供了一个缓存目录 FileOutputStream fos = new FileOutputStream(file); int len = -1; byte[] buffer = new byte[1024];//1kb while((len=inputStream.read(buffer))!=-1){ fos.write(buffer, 0, len); } fos.close(); inputStream.close(); //2.8通过位图工厂获取bitmap Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath()); //2.9把bitmap显示到iv上 Message msg = Message.obtain(); //使用Message的静态方法可以减少对象的创建 msg.obj = bitmap; handler.sendMessage(msg); //iv.setImageBitmap(bitmap);  } } } catch (Exception e) { e.printStackTrace(); } }; }.start(); } }