android url.parse,android原生类实现简单网络操作（url，connection，"parseJSON"）

android原生类实现简单网络操作(url，connection，"parseJSON")

18.9.4

注意事项

网络操作需要保证线程的安全性

注意网络线程中对UI现成的反馈

点击事件

//点击事件部分代码

//其中operate是在xml中对空间定义的onClick属性的值，如此可以不用在java代码中设置onClickListener

public void operate(View view) {

switch (view.getId()) {

case R.id.request_bt:

new Thread(new Runnable() {

@Override

public void run() {

requestDataByGet();

//requestDataByPost();

Log.i(TAG, "operate: requested");

//快捷键logi

//logt生成类的tag

}

}).start();

break;

case R.id.parse_bt:

//downloaded为Activity中的boolean变量

if(downloaded) {

handleJSONData(mResult);

Log.i(TAG, "operate: parsed");

} else{

Toast.makeText(this,"尚未下载文件！",Toast.LENGTH_SHORT).show();

}

break;

/* case R.id.net_return://返回上一级，在此处不重要

Intent returnAction= new Intent();

returnAction.setClass(this,ActionActivity.class);

startActivity(returnAction);

break; */

}

}

Get请求获取数据

private void requestDataByGet() {

try {

URL url = new URL("http://www.imooc.com/api/teacher?type=2&page=1");

//不太明白open的意思

//HttpURLConnection是抽象类，url.openConnection()返回的HttpURLConnection是

//其他包下的继承本类的对象(sun.net.www.protocol.http.HttpURLConnection)

HttpURLConnection connection = (HttpURLConnection) url.openConnection();

//设置连接属性

connection.setConnectTimeout(10 * 1000);

connection.setRequestMethod("GET");

connection.setRequestProperty("Content-Type", "application/json");

connection.setRequestProperty("Charset", "UTF-8");

connection.setRequestProperty("Accept-Charset", "UTF-8");

//发起连接

connection.connect();

//类似404等访问结果

int responceCode = connection.getResponseCode();

String responseMessage = connection.getResponseMessage();

if (responceCode == HttpURLConnection.HTTP_OK) {

//将connection-->流-->String

InputStream inputStream = connection.getInputStream();

mResult = streamToString(inputStream);

//streamToString是自定义工具方法

//这一处runOnUiThread线程很重要，直接操作会产生程序崩溃

runOnUiThread(new Runnable() {

@Override

public void run() {

mResult = decode(mResult);//unicode --> utf-8

displayTextView.setText(mResult);

}

});

} else {

//TODO: fail

Log.e(TAG, "request errorcode: " + responceCode + ", message:" + responseMessage);

}

} catch (MalformedURLException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}finally {

downloaded = true;

}

}

为Post请求时

///...

// ?type=2&page=1

URL url = new URL("http://www.imooc.com/api/teacher");

HttpURLConnection connection = (HttpURLConnection) url.openConnection();

connection.setConnectTimeout(30*1000);

connection.setRequestMethod("POST");

connection.setRequestProperty("Content-Type", "application/json");

connection.setRequestProperty("Charset", "UTF-8");

connection.setRequestProperty("Accept-Charset", "UTF-8");

connection.setDoOutput(true);

connection.setDoInput(true);

connection.setUseCaches(false);

connection.connect(); // 发起连接

//本例中无法实现，因为服务器后台并未设置接受Post请求

//getEncodeValue的含义是将字符串强制设定为utf-8

//一般username=xxx&password=xxx

//get请求完全不具有安全性 post请求具有安全性

String data = "type=2&page=1";//"type="+getEncodeValue("2")+"&page=" + getEncodeValue("1");//"username=" + getEncodeValue("imooc") + "&number=" + getEncodeValue("150088886666");

OutputStream outputStream = connection.getOutputStream();

outputStream.write(data.getBytes());

outputStream.flush();

outputStream.close();

//...

parse解析取得的源码

private void handleJSONData(String result) {

try {

//LessonResult为结果集+status+msg，Lesson为一个data对象内容的承载类

//Lesson中只有gettersetter等

//两个类都很好写

LessonResult lessonResult = new LessonResult();

//java中通过JSONObject类处理JSON文件

//直接用字符串result初始化JSONObject

JSONObject jsonObject = new JSONObject(result);

List lessonList = new ArrayList<>();

//直接调用内部的方法，通过键，从自身内容中取出对应的值(值的类型需要设置)

int status = jsonObject.getInt("status");

JSONArray lessons = jsonObject.getJSONArray("data");

lessonResult.setStatus(status);

if(lessons != null && lessons.length() > 0){

for(int index = 0; index < lessons.length(); index++){

JSONObject lesson = (JSONObject) lessons.get(index);

int id = lesson.getInt("id");

int learner = lesson.getInt("learner");

String name = lesson.getString("name");

String smallPic = lesson.getString("picSmall");

String bigPic = lesson.getString("picBig");

String description = lesson.getString("description");

LessonResult.Lesson lessonItem = new LessonResult.Lesson(

id, learner,name,smallPic,bigPic,description);

lessonList.add(lessonItem);

}

lessonResult.setLessons(lessonList);

}

displayTextView.setText(lessonResult.toString());

} catch (JSONException e) {

e.printStackTrace();

}

}

JSON结构请点进url

工具方法 stream2String + decode

/**

* 将输入流转化为字符串

* @param inputStream

* @return

*/

//使用buffer承载inputStream中的字符，再向ByteArrayOutputStream写入

//再通过byteArray()初始化String

//此处理解还需加深

private String streamToString(InputStream inputStream) {

try {

ByteArrayOutputStream baos = new ByteArrayOutputStream();

byte[] buffer = new byte[1024];

int len;

while ((len = inputStream.read(buffer)) != -1) {

baos.write(buffer,0,len);

}

baos.close();

inputStream.close();

byte[] byteArray = baos.toByteArray();

return new String(byteArray);

} catch (IOException e) {

Log.e(TAG, "streamToString: "+e.toString());

return null;

}

}

/**

* 将Unicode字符转化为UTF-8字符

* 是工具类

* @param unicodeStr

* @return

*/

private String decode(String unicodeStr) {

if (unicodeStr == null) {

return null;

}

StringBuilder retBuf = new StringBuilder();

int maxLoop = unicodeStr.length();

for (int i = 0; i < maxLoop; i++) {

if (unicodeStr.charAt(i) == '\\') {

if ((i < maxLoop - 5)

&& ((unicodeStr.charAt(i + 1) == 'u') || (unicodeStr

.charAt(i + 1) == 'U')))

try {

retBuf.append((char) Integer.parseInt(

unicodeStr.substring(i + 2, i + 6), 16));

i += 5;

} catch (NumberFormatException localNumberFormatException) {

retBuf.append(unicodeStr.charAt(i));

}

else {

retBuf.append(unicodeStr.charAt(i));

}

} else {

retBuf.append(unicodeStr.charAt(i));

}

}

return retBuf.toString();

}

来源: imooc.com